# Model Engine Ignitions



## 74Sprint

Well I'm slowly finding time to make some model engine ignitions and for my race car. I am developing several different types of ignitions I am hoping to sell here, my web page, and on other sites. Once I have the designs ironed out I'll get a vendor membership for here and sell them. But in the mean time I would like some feedback on the designs. Can't promise to incorporate them but I'll try. So follow along and see what happens, R&D research and destruction.

I'll be offering the ignitions in 3 versions, just the board, full kit, and preassembled versions. No I don't have a final price yet but kits should range from $30 to less than $100 dollars depending on features and model. The versions range from a simple buzz coil to fully programmable sequential ignition timing. I have learned from manufacturing other equipment, mostly industrial stuff like hardware and software, that it is hard to please everyone. But that does not mean that I can't offer some choices. I spent most of the winter designing these boards to allow one to choose to use certain parts by leaving them out and just bypassing the part, I'll explain more later. I would like to say that I may appear to be new here but I'm not. I'm also not new to the internal combustion process (deflagration). Yes I'm also fully aware that there are others offering ignitions and there are lots of DIY'ers out there but this is just my offering. I am also a very firm believer in the "K.I.S.S. System". I tried to make the boards user friendly for soldering. The way I see it, if I find it easy to solder them then others should be ok, if not then I'll redesign the boards. The boards can either use my custom designed coils or you can use your own, just run wires to your coil.

The boards, a work in progress:
I used new software to design these boards "Dip Trace" it is the best I have used so far for the price and I have used software from Win-Draft to OrCAD, so $50 to $5,000 or more.
The first one below is my Buzz coil "IDI-ADJ-BZ-HV" or Inductive Discharge Ignition, Adjustable, Buzz, High Voltage". I did research about Buzz Box ignitions and found that there was timed and untimed boxes. I can't see why anyone would want to use untimed today. The "IDI-CD4047B" or Inductive Discharge Ignition using a CD4047B which is a one-shot multi-vibrator that operates from 3.5v to 18v. Both the IDI-ADJ-BZ-HV and the IDI-CD4047B use the CD4047B set for non retriggerable so that it can't refire until the current trigger pulse is done. This also means that if the engine is stalled at a trigger point the coil current shuts off after the pulse. The CD4047B needs to see a rising or falling pulse in for a trigger. The ignition coils I had made were based on an inductive coil that I had them modify so it can work in IDI or CDI. I don't like the term TCI because maybe I won't use a transistor.

Features for Buzz:
-Operates from 4.7v to 18v, higher the voltage the stronger the spark. But normally set for 5v using a reg for above 6v in.
-Auto Advance with RPM, if you want. Selectable (fixed or auto) or leave out the switch and hard wire a jumper.
-Use either points, inductive, or Hall-Effect trigger (min 3.5v trigger source).
-Max auto advance is controlled by the distance between the Hall-Effect to magnet.
-Use trailing edge with points, inductive, or Hall-Effect to get auto advance.
-Use my coil or yours.
-Adjustable number of sparks and at what frequency, this is so you can use your own coil, each coil is different. The dwell time R3 is the window for the sparks, frequency R7 is the actual number of sparks.
-Self resetting fuses.
-3" (76.26mm) long x 2" (50.49mm) wide.
*Buzz*






Features for IDI CD4047B:
-Same as the buzz coil board but puts out just one spark. Less parts also.
-Adjustable dwell time R3.
-2.75" (69.79mm) long x 1.75" (44.38mm) wide
*IDI CD4047B*





Features for CDI Sparky-1:
I originally made this board to work with R/C plane engines and it works very well. With 11.7 volts in it will make sparks up to 37,200 RPM on a single cylinder operation, 21,000 RPM at 5v operation. Average HV is 27,000 or 18,000 at 5v and 32,000 at 11.7v.
-Capacitor Discharge Ignition.
-As low as 400ma current consumption, can go lower but the spark is weak.
-Uses an external trigger and power source. I'll probably change the external regulated power source to internal.
-Needs a 5v external trigger in. Doesn't matter what type but must be at least 5 volts.
-Voltage in is 5-12 volts. I have ran it with 4.5 volts.
-Uses a hic-up circuit so that once the capacitor is charged it turns the charging circuit off and on as needed to keep the capacitor charged and reduce power consumption.
-Charing voltage is 1,000v at 1,000 RPM (single) and 100v at max RPM, max RPM depends on voltage supply.
-Has a separate Kill Switch in line.
-Sparky-2 and 3 in development. Less parts and better performance I hope.
-3" (76.43mm) long x 2" (50.73mm) wide.
Vid Prototype development 1
Vid Prototype development 2
*Sparky-1*





Features for Universal Trigger Board CD4047B:
I designed the Universal Trigger Board to put out a signal from just about anything. I also designed it work with small engines to automotive use.
-It is a signal conditioner. Signal in square wave signal out of 5-15 volts.
-Will work with points, inductive, or Hall-Effect trigger, has built in weak single boost op-amp.
-Use the Hall setting for points and Hall-Effect.
-Use HEI setting for inductive coil weak signal setups.
-Use with Sparky-1 board.
-Fixed or Auto-Advance
-2.75" (69.85mm) long x 1.75"(44.45mm) wide.
*Universal Trigger Board CD4047B*





Well these are my simplest boards but, I could have made something as simple as the TIM-6 board but that to me is too simple. But wait, you can use either the Buzz board or the IDI-CD4047B board as simple as the TIM-6 board it's just a matter of choosing what you want and bypassing everything else. For example: if your using a 6v battery you can jumper F1, jumper the input pin of the voltage regulator to the output pin, if you want just fixed timing then leave out the switch and jumper pin 3 or 4 of the switch to pin 2 of the switch, for auto-advance same thing but jumper to pin 5 instead of 2, and so on. These board designs are not locked and I only ordered 5 of each as prototypes for R&D purposes. If someone want's to try one contact me, just pay me for the board and shipping, I'll probably sell 3 of each and any extra parts I have like coils and such. Oh the boards already have a spot for the pull-up resistor for the Hall-Effect so it should be just a matter of putting a 1.5k ohm resistor in and connecting a Hall. Oh the regulator is mostly for the Hall-Effect depending on which one you choose.

How the auto-advance works:
The auto-advance works by using the trailing edge (negative going) of the input signal. It doesn't matter if you are using  either points, inductive, or Hall-Effect trigger, as RPM goes up the trailing edge will move closer to the leading edge and so timing will advance from it's initial position. For points you put a 10k ohm resistor in for R1, put a 10k ohm resistor between SIG-IN and S-, then put the points across S+ and SIG-IN. This will give a high when the points close and a negative going low for the auto-advance. You can't control the max advance with points (yet) but you can with a Hall or inductive pickup. When you move the Hall-Effect or inductive pickup away from the magnet the whole pulse width will shrink. So you just reset the initial timing and the auto-advance will now advance less.

Current research:
Currently I'm working on a programmable ignition timing interface. Using an Arduino Nano the interface will allow me to use either points, inductive (HEI), or Hall-Effect trigger working off the crank or distributor signal to program 200 points at 50 RPM increments. The PITI is to replace the mechanical advance on my race car, I don't use a vacuum advance, to much power for that. The interface goes between let's say the dizzy and the ignition box. In my case a Crane High 7 ignition box. The interface is similar to the UT board but, programmable with all the bells and whistles I want and need for drag racing. It's also scalable up or down. Eventually it will do sequential ignition firing from 2 to 20 cylinders or more if I want but, that's getting ahead of myself and I have my racecar to get ready.

Anyway let me know what you people think or if you have any questions just ask, I'll get back ASAIC.

Ray


----------



## petertha

Interesting. Can you show some examples of the RC installations you did? Were they single cylinder or multi? I'm slowly finishing a methanol glow radial. Gasoline/spark would have been the preference but at least at my level it was opening up yet another can of worms. I've seen smaller more scale like plugs and I've seen some conversion ignition kits but I haven't delved too deep. Plus I'm electrically 'challenged' Lol.


----------



## 74Sprint

petertha said:


> Interesting. Can you show some examples of the RC installations you did? Were they single cylinder or multi? I'm slowly finishing a methanol glow radial. Gasoline/spark would have been the preference but at least at my level it was opening up yet another can of worms. I've seen smaller more scale like plugs and I've seen some conversion ignition kits but I haven't delved too deep. Plus I'm electrically 'challenged' Lol.


Unfortunately because of health reasons I had to give up working on the ignitions 3 years ago and I'm just picking it back up. This all started years ago on RC Groups and I was part of the group working on a project called "Programmable-Open-Source-CD-Ignition-PIC1840". We did have running engines and I had purchased some engines for testing myself but I didn't make it there. This stuff here in this thread is pretty simple and straight forward.

One day I hope to make a radial. If your going to use a distributor then an ignition would be fairly easy but, if you want to go distributor-less then that would require 1 ignition coil for each jug. Or if you want to use a dizzy just for spark distribution that would be ok also. For my Olds 455 I'm using a 5.0 litre (302) cam sensor assembly (replaces the dizzy), crank sensors (4 in a aluminum pulley), and 8 near-plug coils. I haven't built that ignition yet, I wanted to do these other ones first. Track is closed right now because of covid-19. For your engine I would wait until I get my programmable ignition for small engines done, I'm working on that right now. This way you can tell the micro-controller where your cam and crank sensors are and it takes care of the rest, you just need to set your ignition curve after that. By where I mean how many degrees BTDC they are. Sync pulse would most likely be for # one. I have seen where people have tried to use just 1 coil and electronically distribute the spark but, that didn't work out very good.

As for examples; I will be doing a Tiger 26cc 2 stroke, a 2 stroke OS60, and once it is rebuilt an ASP 65 Four Stroke, all singles. I'll post videos to my You Tube channel when they are done. My question is 'where would you get the cam timing from on a scale radial'?

Ray


----------



## petertha

Re cam timing you would either have to measure it directly from the engine with the usual protractor wheel observing TDC & rocker/valve lift. Or get the  IO,IC,EO,EC info from manufacturer specs (assuming they reference it, which often they don't). Or in the case of engines from plans, reverse engineer it as I had to do. But from ignition perspective, I've seen links where people have converted methanol glow plug engines to gasoline spark ignition & basically referenced spark X degrees off TDC. The cam timing just is what it is. Like most things, I suspect there there is likely variation & tuning relative to the engine itself. I'm also not clear if/how advance/retard is somehow integrated into these solid state systems, haven't got that far myself.

Popular conversion reference








						What Do You Know About GLOW CDI Conversion? - CH-ignitions
					

CDI system is an electronic device which is used to store an electrical charge over the circuit capacitor. CDI which is abbreviated as Capacitor Discharge Ignition is a vital part of the machine. The electric current is discharged with the help of the ignition coil, and it produces a powerful...




					ch-ignitions.com
				




Example gasoline multi-cylinder engines with corresponding ignition modules. Some work better than others form what I've gathered. Another issue specific to RC is EM noise. 





						4-stroke engines | SAITO SEISAKUSHO CO., LTD.
					

Instruction manualsRADIAL ENGINESFG-73R5The long-awaited 5-cylinder series since the Glow FA-325R5 is a Gas Version.  This is what we call "The ultimate sound".FG-90R3The bored-out version of the FG-84R3. The



					www.saito-mfg.com


----------



## 74Sprint

Yah I guess I should have explained better. I could do the same setup as CH Ignitions which is a wasted spark setup for radials, that way there is no need for a cam sensor or dizzy. The sync pulse for #1 cylinder comes off the same rotating hub as the crank position signals. One has to remember that micro controllers (MCU) and micro-processors (MPU) can not predict the future and they need time to do the calculations and look-ups. So the magnets need to be placed say 45 - 90 degrees before the firing time it all depends on how much timing advance you want and MCU calculation time. To put more advance into timing you put less delay in firing. I'm sure you are aware that some engine builders want true scaled down parts and are willing to spend the time and money to get that look. If true looks is not a problem then the below setup is the way to go. In the picture below from CH Ignitions I drew an arrow pointing out the sync magnet for cylinder #1. This setup below is the easiest way to do it. The black magnet is #1 for lining up the firing order and the magnet before it is there to tell the MCU that the next pulse is going to be #1 cylinder. This can be done either by timing the pulses or by using 2 Hall-Effects, say N-S for cylinders and one S-N for syncing #1 cylinder. In this case 8 magnets are used but, one could also just use one magnet and sense notches or teeth to do this as in automotive. For my Olds 455 I'm going with 8 coils for the cool look LOL. Converting a glow engine to spark is fairly straight forward for fixed timing or simple auto-advance but, a programmable timing one is more difficult. As for cost between a single output one and the one shown below is 7 coils instead of 1 and about 16 more micro chips, still need those plug wires. As for EMI/EMF, if weight is not a problem then that is easy to take of.






Ray


----------



## stevehuckss396

Well I would probably purchase one to try. I have a 9 cylinder radial about half done and will need an ignition system. I also have a v8 85 percent done so 37k spm sounds good to me.


----------



## 74Sprint

stevehuckss396 said:


> Well I would probably purchase one to try. I have a 9 cylinder radial about half done and will need an ignition system. I also have a v8 85 percent done so 37k spm sounds good to me.


For a really good spark I need 0.0025 seconds (2.5 milli-sec) between sparks for a good spark which means your radial could do 24,000 RPM. For the V8 which requires 4 sparks per rev would top out between 10,000 - 40,000 RPM using 1 coil, with 4 coils it would top out at 40,000 RPM using 12 volt supply. The coils I use require 1.5 milli-sec to charge and 1 milli-sec to dis-charge which limits the RPM. Because with the CDI I charge up to 1,000 volts it has a really good spark at idle, good for anti-fouling. The charge voltage goes down as RPM goes up and this happens with all CDI's no matter who makes them. Most CDI's will work down to @100-150 volts on the primary and the coils are usually 100:1 winding ratio so output on the secondary drops down to 10-15,000 volts. My coils are 200:1 ratio but that does not mean that my secondary output is 200,000 volts because CDI ignitions don't work that way. The impedance of the capacitor and coil really knocks things down.
I usually try to get someone I don't know personally to test a system so long as they agree to give me honest detailed feedback and understand that they would be working with a beta-prototype (prerelease system), I'll keep your hat in the ring if you want. I should have testing samples by the end of August.

Ray


----------



## 74Sprint

So why am I making these boards/systems? Well it's because *I* need them for myself and I figure others could use them also. Now I'm a bit of a perfectionist which means I'm usually never satisfied with something until I can abuse the sh_t out of it and it survives R&D. I've been fascinated by and studying IC engines for 46 years now. From 020 Peewee engines to blown alcohol engines to 20 cylinder EMD 645 diesel engines, I still want to make a scale SD40-2. So far most of the electronics I make is for stuff I use/need or stuff I invent and license to companies to make and sell. Well that's enough about me.

I've been checking the boards I have shown above, usual QC stuff because the boards came on a slow boat from China and I'm using new software (Dip Trace) for designing boards. I already don't like the clearances around solder points and I have to increase the clearance, otherwise one would need a fine tip soldering iron and steady hand. Other than that they seem ok for now.

None of the boards use surface mount parts which adds to the cost but, not everyone can solder surface mount parts. The Sparky-1 board uses a SMD transformer to up the voltage for the CD but, the tabs are big enough and spaced enough for easy soldering. You will need fine resin/rosin core solder to solder the boards. 

I'll be providing YouTube videos and resource material on my website as work progresses.

Ray


----------



## bluejets

Hi Ray,
           One of the biggest problems with the 1840 and earlier was it didn't seem to matter what effort most put in, there was always a request for something different. Seemed no one was satisfied no matter how it was presented.
That combined with, as I remember it, the hurdle of getting enough energy for high speed ignition into the cap in the short period of time.
Poor old Gompy near pulled his hair out on many occasions.


----------



## 74Sprint

bluejets said:


> Hi Ray,
> One of the biggest problems with the 1840 and earlier was it didn't seem to matter what effort most put in, there was always a request for something different. Seemed no one was satisfied no matter how it was presented.
> That combined with, as I remember it, the hurdle of getting enough energy for high speed ignition into the cap in the short period of time.
> Poor old Gompy near pulled his hair out on many occasions.


I remember all that. I got ahold of Microchip for help with the PIC1619 but, they didn't seam to care about that chip. They also didn't seam to know much about the chip other than the basic resources so I started looking into other options. I really didn't want to take a lead on the 1840 because I was busy with my computer business. Now that I'm semi retired I have more time to play around I guess one could say. I started looking around for a processor and IDE that was more or less for beginners and chose the Arduino Nano. Early testing with the ATmega328P shows it only needs 5 - 7 clocks per instruction which is nice. I haven't tested the FPU on it yet but, I feel confident in it. I'm just going to mount the Nano boards straight onto a mother/daughter setup. I have learned C# and have been making GUIs that work with the Nano USB for programming variables and the EEPROM lookup tables on a Nano.

I'm not going to try and satisfy everyone's wishes. Small changes, yes, big or custom no. Yah it's to bad Gompy couldn't make ago of things. I know how hard it can be running a small business. I had to give up my computer support business, the stress gave me permeant heart problems, so I go slower now and enjoy my grandkids.

Take care
Ray
Some of my test boards


----------



## Willyb

Hi Ray
I would certainly be interested in helping you out any way I can.  Using the Arduino Nano is a good way to go.  It will be nice to have another ignition system available for our model engines.
Cheers
Willy


----------



## bluejets

Hi Ray,
            You might want to give some thought also to using the Arduino pro mini and programming it through a usbasp programmer.
I have found it to be more positive programming result than normal especially if using some clone boards.
Easy to do and with the pro mini a lot samller installation.
Video below is about custom bootloader but process for standard code is the same.


----------



## mccreamark

++ for Arduino here  and the pro mini especially for battery powered projects, I use them regularly at home and at work (R&D engineer). If you need more speed or sophistication you can go for the Mega or Due same IDE.  I also use the Texas Instruments Launchpad boards on the Energia IDE which is a clone of the Arduino IDE. They have an array of processors and Fram for storing data.


----------



## bluejets

Speed for size etc. etc. etc............ is as Ray already showed in the ESP32.


----------



## 74Sprint

Thanks bluejets & mccreamark about the Pro Mini. I also looked at the Pro Micro which uses the ATmega32U4 which is nice and it should work. It has the 0 &1 ex-int which I need and of course the PCINTs. I to have been looking at the TI line and I'm committed to using the STM32 line with ARM M4 and the M0 cores for a major project but those would be overkill for these little projects. STM is the only manufacturer that I could find that had an RTOS that is UL certified and that took me 9 months to get it from them. My only concern with the Pro Mini is the lack of a native USB port for uploading the parameters. Mind you at this point just about everything can be changed. The PIC12F1840 was an experience in being conservative and maximizing resources. My ignition controller interface uses the following:
•    3 adjustable rev limiters in 50 rpm increments
   o    1 for burn out use a switch
   o    1 for staging – foot brake (switch) or trans brake
   o    1 for Max rpm
•    Adjustable timing in 50 rpm increments to 10,000
•    Adjustable timing by the tranny gear- use switches (3)
•    Trick shift timing retard by switch or rpm in 0.001 sec. increments (1)
•    Start up retard ignition timing by 1 degree increments – use starter solenoid signal (1)
•    Hall effect 5v – 20v, 12 volt signal out. Universal trigger board (RPMin pin 2)
•    GM style HEI signal compatible op-amp (RPMin pin 2)
•    Water/Engine temp (pin 10)
•    Uses 5 Inputs ?

I'm not sure if a 16 MHz 8-bit CPU can do what I need but I have to weigh flexibility to cost. I'll go up in CPU power and features as required. Eventually I will combine everything into a stand-a-lone sequential distributor-less ignition. We have the sequential distributor-less ignition but it is not programmable. It can however hook up with an MSD programmable ignition controller but now the cost jumps up to $1,100 USD, ouch.

Anyway by using the Arduino IDE and either the Nano, Mini, or Micro the cost stays down and is easy to learn. Hopefully I can have something running this weekend. Oh I either have to fix my timing light or make one (Gompy style) 

Ray


----------



## Vietti

Admit I know next to nothing about building one of these, I'm a magneto guy.  I have S&S ignitions that work great.  A feature to consider is making the timing light standard, very handy, and I have wanted the cheap plug in tach offered on the RCEXL ignitions, can you do it?

John


----------



## 74Sprint

Vietti said:


> Admit I know next to nothing about building one of these, I'm a magneto guy.  I have S&S ignitions that work great.  A feature to consider is making the timing light standard, very handy, and I have wanted the cheap plug in tach offered on the RCEXL ignitions, can you do it?
> 
> John


I have the timing/tach light on all the ignitions and I could make it so one could use the RCEXL one or add something in. Speaking of RCEXL I have sourced out the same parts that they use such as the Hall-Effect holder and sparkplug caps & wire. I am also working on a programmable Krober Magneto CDI but it has proven to be a challenge, CPU keeps resetting. Firstly I need to get the basic stuff nailed down and get some testing done before moving on.

Ray


----------



## Willyb

Hi Ray
I would second the addition of a simple Tach like the one used with the Rcexl Ignition systems. To make it less work for you, why not just use the Rcexl one.
Looking forward to this project.
Cheers
willy


----------



## 74Sprint

Willyb said:


> Hi Ray
> I would second the addition of a simple Tach like the one used with the Rcexl Ignition systems. To make it less work for you, why not just use the Rcexl one.
> Looking forward to this project.
> Cheers
> willy


That's what I'm thinking.

Ray


----------



## 74Sprint

Well my saga continues. Normally I would not discuss any project that is in the works but, I feel this time I want people to see the amount of work it takes to make quality parts. Because I'm not designing something custom I have to give the end user some options. For example to replace the simple TIM ignition with something more modern one can use the CD4047B demo circuit below.

Ignition Using CD4047B.pdf




Board Top Layer.pdf
Board Bottom Layer.pdf 

If you want anyone can play with the circuit. R1 & C1 control how long the pulse width is which controls the dwell for the best spark. The nice thing about using a 1 shot is it can be set to non-retriggerable which means it can't be re-fired until it is finished firing the present pulse. Also to say if the engine stops turning and the points should be closed or the Hall-Effect stops on the magnet the power to the coil shuts off after the pulse is done and won't turn back on until the next rev.

Anyway, because I'm using new software (Dip Trace) and boards from a new supplier you never know what your going to get until you get the boards. So as I mentioned I don't like the clearances around the solder pads and now I'm finding some of the holes are too small, more changes. The holes are plated through holes and I find the holes in Dip Trace are not allowing for the plating so they are about 0.001"-0.002" too small. Also my pattern for my spark coils are off a bit, I need to redesign the pattern. As you can see the pins are at an angle, also the holes are a bit tight.




I also have to order some parts from Digi Key. I thought I had them but nope. Anyway, I'll get this Buzz Board working soon.

Ray


----------



## scottyp

Definitely use the IGBT's to drive ignition coils, it will save you a lot of headaches.


----------



## 74Sprint

scottyp said:


> Definitely use the IGBT's to drive ignition coils, it will save you a lot of headaches.


Thanks Sol, I have used transistors, MOSFETs, IGBTs, SCRs, and specific components designed only for driving automotive ignition coils. It all really comes down to "what is the best device for the application of the circuit that won't break the bank." Now that may or may not make sense but, these are simple low cost ignitions. I'm still developing them and I probably have a couple of hundred dollars worth of transistors, IGBTs, and MOSFETs to play with and I have 5 boards of each type to play with or blow up LOL R&D. I do believe in NDT (non-destructive testing) but, that won't show what the limits are of what one has created. NDT has it's place if you are working with something that is difficult or cost prohibitive to replace. I will be testing these ignitions with transistors, MOSFETs, IGBTs to see which one meets my standard for low heat, efficient spark, and durability.

I am working on an improved ignition that I created years ago for my race car. That sucker is a multi-spark inductive ignition that draws 48 amps when charging and it put out a 100,000 volts at 1 amp spark that according to engineers is impossible to work. It used a bank of 2n3055 transistors but could only run for 15 minutes before it got too hot and smoked. At 30 amps it worked very well, 75,000 volts and 0.5 amp spark. It increased the gas mileage on my old truck by 30% and lowered my emissions by up to 75%. The new design (CDI) uses IGBTs and draws 56 amps charging but, the EMI/RF interference is horrendous. The old ignition was purely analog and the new is digital. Along with the EMI/RF bothering the digital design I also have voltage droop so I may have to cut back the current draw. The nice thing about the old design was that it allowed me to reduce the timing advance without power loss and the crank/rod bearings showed less wear. There is a ton of more stuff I could talk about but, that is for another time.

Ray


----------



## 74Sprint

The tentative price for the Buzz coil KIT "IDI-ADJ-BZ-HV-KT" is $40.00 CAD plus taxes if needed and whatever the postal rate is for shipping.

Ray


----------



## bluejets

Remember this bloke used to come into Dad's garage with all these fuel saving wonders stuck everywhere.
When added up, Dad would say" have to watch this bloke if he comes in for fuel as he'll be putting gas back into the bowser"
Saving devices added up to over 200%......


----------



## Gordon

bluejets said:


> Remember this bloke used to come into Dad's garage with all these fuel saving wonders stuck everywhere.
> When added up, Dad would say" have to watch this bloke if he comes in for fuel as he'll be putting gas back into the bowser"
> Saving devices added up to over 200%......


I remember hearing a story about this guy who installed a gas saving carburetor, ignition, spark plugs and every other device advertised as fuel saving. He drove 20 miles down the road and his fuel tank overflowed.


----------



## dsage

"It increased the gas mileage on my old truck by 30% and lowered my emissions by up to 75%. "

The car manufacturers would love to hear from you.


----------



## 74Sprint

bluejets said:


> Remember this bloke used to come into Dad's garage with all these fuel saving wonders stuck everywhere.
> When added up, Dad would say" have to watch this bloke if he comes in for fuel as he'll be putting gas back into the bowser"
> Saving devices added up to over 200%......


I know exactly what you mean. When I was doing my mechanic apprenticeship when I just got out of high-school we used to have a few salesmen trying to get us to sell their wonder products. In that one would wonder 'what the hell is he trying to sell us'. All kinds of things would come into the garage, from devices that would put air into the fuel to heating the fuel, LOL can you say fire. And then we would get customers coming in asking us to fix their wonder device because the car wouldn't run properly, LOL and then we would remove the device and just do a proper tune-up and the they were amazed how much better the car ran. But in my case I have actual witnesses and some documentation. This is not a B.S. story.

Ray


----------



## 74Sprint

Gordon said:


> I remember hearing a story about this guy who installed a gas saving carburetor, ignition, spark plugs and every other device advertised as fuel saving. He drove 20 miles down the road and his fuel tank overflowed.


LMAO I like it.

Ray


----------



## 74Sprint

dsage said:


> "It increased the gas mileage on my old truck by 30% and lowered my emissions by up to 75%. "
> 
> The car manufacturers would love to hear from you.


Yes and no. Yes they would be interested but, no they wouldn't be. I have talked with a GM engineer through a friend and a Chrysler engineer through my brother both engineers were retired and both have now passed away. What they both told me was to forget it unless I was willing to practically give it away for free and also make it less expensive than what they are currently using. Well I'm not going to sell the licensing for 1% of net and there is no way I can make it cheaper than what they are using now. Remember when GM had problems with their ignition falling out or turning it's self to the off position? Well GM tried to save $0.15 on each lock (approx.) and they screwed themselves. Now 15 cents may not sound like much but, when you multiply that by 500,000 or 1 million then that is someone's yearly bonus $75,000-$150,00. When I worked for CP Rail, CP lost a contract to haul coal by $0.02 a ton. When your talking about 5,000,000 tons a year that's a lot of money. Right now I get between 7% and 10% of gross sales on licensing my products, there would be no way I would go for less than that. Car companies are notoriously known for screwing people over. Think of things like delay wipers. Also how come the auto makers don't use MSD products? Here is something else, when car manufactures make parts from raw materials they sell the parts to their warehouse, the warehouse sells the parts to manufacturing and then they sell the car to warehousing which sells the auto to the dealers. It's all legal and allowed accounting in the US and Canada. Parts work the same way raw manufacturing and/or third party sells to the main warehouse, the main warehouse sells to the distribution warehouse, the distribution warehouse sells to the dealers, and dealers sell to consumers, each time it changes hands the price goes up.

There is one thing that is bad about my maxed out ignition and that is it doesn't work well with hemi head style engines which, almost all automobiles today use. It likes to blow holes through the sparkplug boots to the valve covers or tubes. Another bad thing is the amount of current draw needed to give the sparks that is needed to almost fully burn the fuel. Yes I have had friends and family tell me that the car companies would like to see it but, they are not looking at all the problems when dealing with car companies. As for racing; I was doing some testing with Doug Doucette hear in Winnipeg. Doug has set a few world and national records with his nitro burning NA TAD dragster. In case some people aren't away, nitromethane is very hard to get it to burn in a cylinder when at 95-98% which, is why they always start the engines with regular gas or alcohol to get the cylinder temperatures up. You can light it with a match and it burns but, don't hit it with a hammer it explodes. Doug was willing to experiment with getting rid of the sparkplug boot problem. What killed the project was NHRA, they refused to allow it to be used by any racer. Right now all TF, TF/FC, TAD, TA/FC cars can only use MSD's listed products, I think some sort of kickbacks are used here, pi_s me off.

I will say this much about my maxed ignition, it takes advantage of what everyone else is trying to get rid of. It uses what I call regenerative coil charging. If one can understand inductive resonance and how coils especially auto-transformers (automotive ignition coils) work then that would be the basics of it. Auto-transformers or automotive ignition coils are wound usually almost always with the secondary winding on top of the primary which of course is wound on the laminated iron core. So the magnetic field cuts through the secondary when charging and discharging. The field also cuts through the primary when the field collapses which causes and shows up as ringing on the wave form, not just on the secondary. This ringing or kickback also shows up on a single coil (relay) which is why we use diodes or snubber circuits to eliminate or suppress them. You also have current wanting to continue flowing in the same direction when a circuit is broken, we use condensers with points to protect the points. But what if you had a way to enhance these effects? Well I do, the spark voltage at the primary starts out at 12-14.5 volts and with each spark of a sequence up to 6 sparks per firing, energy that would be normally be lost is put back into charging the coil. The primary voltages can rise as high as 1,200 volts or more. The sequence will raise the voltage until it discharges somewhere, anywhere but it will discharge. All ignitions will misfire occasionally but, in my case when that happens the voltage across the primary nearly doubles to quadruples. But I will not tell anyone how I do it not until I get some bugs worked out and patented. Slowly turning the dizzy manually it is really good at lighting cigarettes, try that with your ignition.

I have been studying and working with the process of how IC engines work for 46 years now, from charge intake to lighting it to exhausting it. Air streams into the intake runners to swirl in cylinders to deflagration to combustion chamber and piston design. Oh yah all IC engines need detonation, it comes at the end of the deflagration process. I have never heard what people call detonation, I have heard knock from bearings being hammered because of too much timing and trying to turn the engine backwards. This also shows up as cap walk. I have heard pinging only once in my life time, it was on my car and it sounds exactly like a ping, wrong plugs when cross referenced, too hot of ground electrode, a little too much reach, I was in a rush and had the parts guy look them up. OS's new RC glow plugs for gasoline engines use this action. 

This isn't my first time at the rodeo so to say guys but, I can understand the disbelief. If I hadn't seen the results myself I wouldn't believe it either. When people say "yah right, sure it can" wink wink, it doesn't really bother me because I'm a 'show me to prove it person' also.

I blew all the transistors in about 10 seconds because I forgot to put the ground lead on, it did make sparks about 12" long across my wooden test bench (shown below.) At the time 4 2N3055's here cost me $60 plus I was laid off at the time, so it really hurt. Hell DigiKey now shows them as obsolete LOL. With the new MOSFETs, IGBTs, and also with SiC, GaN, and other new tech devices I think I can iron out the bugs.






I know it's a mess in there but hey it was a prototype.










Yes I know I need to clean it up. My test bench can run up to 15,000 rpm crank speed or 7,500 rpm for the dizzy for a V8. I can use external coils with it. I had to drill holes in the cap because the air in there was ionizing and causing some cross-firing. When running at full power it is quite noisy. I am in the process of making a new bench so I can test small and magneto ignitions.





Ray


----------



## bluejets

Ray,
         I have been using ,with some degree of success, the cdi modules and coils for the "pocket rocket" motorcycles (50cc kids bikes)
Wondered if you looked at those in any way. (12v 4 wire units) 
Picked up 1/2 dozen of each for future use for around AUD$5 a piece back before covid19.


----------



## 74Sprint

bluejets said:


> Ray,
> I have been using ,with some degree of success, the cdi modules and coils for the "pocket rocket" motorcycles (50cc kids bikes)
> Wondered if you looked at those in any way. (12v 4 wire units)
> Picked up 1/2 dozen of each for future use for around AUD$5 a piece back before covid19.


I looked at some ignitions mostly the GY6 stuff. Almost all the pocket bike stuff I could find were 5 & 6 pin AC CDI ignitions. I did find this one DC CDI on Amazon 1PZ UNS-DC4 DC CDI Box 4 Pin. I'm not sure if this is what you were referring to but, the price you paid is excellent. The one I linked to doesn't say what is needed for a trigger, bummer. Do you have a link to the ones you bought?

I just found a wiring diagram, it shows inductive magneto pickup but, no values. I also found a bunch on Aliexpress,

Ray


----------



## bluejets

Hi Ray,
          Yes, things have changed a lot since the B**** virus, post and handling fees included from overseas.
Many 4 pin dc cdi modules available but they can go as high as $50 some times(crazy stuff) 
Do not have original supplier as it appears they went perhaps to dust but there is this one among many I found this morning in a similar price range on Ebay (AUD$8.69...free shipping) but as normal, have to wait for it to arrive.
Used this as a search, I imagine the same/similar would be available to you there........ Ebay search ..... "4 pin dc cdi"

4 Pins DC CDI Ignition Box For 90cc 100cc 110cc PIT Quad Dirt Bike ATV BuggyYXAU  | eBay

I did tests to some degree but my test rig is rather limited and one system works fine on one of George Punters tractors with 1/4" spark plug.
There is a write up in here somewhere but, with a few exceptions, was largely shot down by the knockers.

Model engine CDI easy and cheap

Welcome your opinion but as one has many projects on the go, I tend not to revisit that which is not appreciated. 
Ours work and really that was all I set out to do.

Cheers Jorgo


----------



## 74Sprint

I hear you about your work not being appreciated. I totally forgot your thread there, a couple of days after my last post on your thread I ended up in the hospital for a month from an infection and damn near died. If people want to buy my ignition boards/kits that's fine if not then that's fine to. I think your thread there was admirable and a cool idea.

I started helping a gent in Australia who wants a programmable ignition for his old Yamaha racing bikes using the PIC12F1840 but, I made the mistake of trusting my spice programs and had boards made based on that. BIG mistake, so now I'm going the slow way of making small modules and get them working first then combine them. I also may switch over to using a Nano or just the Atmel328P on my own board.

My big end game plan is to go from these boards to here to a full race ignition for my race car that will use distributor-less ignition using 1 CDI charging unit per cylinder but all controlled by 1 MPU/MCU using a crank and dizzy sensor. Along the way the universal trigger board will get a MCU. There are literally millions of ignitions out there used in automotive racing that are not programmable for timing curves, rev limiters, boost, NOS, and so on. This idea came from the people at the drag/road course and circle tracks here. They mostly run the MSD 6AL, which only handles 1 rev limiter. They simple can not afford a $750 - $2,500 USD ignition so I'm going to make a programmable interface for myself and other racers. No more design one, build one, and then trouble shoot and debug it. I have been buying used parts like MSD stuff and a Crane HI-7 ignition box and coil, I'll buy more if the price is right.

Wife says I can buy a Grizzly all-in-one lathe/mill once we sell the house and down size, can't wait. 
What do you think of using an encoder setup for an ignition?

Ray


----------



## bluejets

Used to follow along in the speedway scene pretty much from when Dad raced TQ's (500cc dirt track) then on motorcross myself ( crazy idea....only 250cc but go like stink) but later as support for the speedway sprintcars. Half a v8 around 400hp, Hawk engines if i remember correctly, came from the States somewhere but they were dual magnetos.
Bit out of my knowledge base there, more up Dad's alley and at 92 I'm sure he'll be able bend my ear on the subject for many hours.
What was the encoder for that you refer to....?? cheers Jorgo


----------



## 74Sprint

I was thinking of maybe instead off a Hall-Effect & trigger wheel setup that most use now that maybe I could try an encoder wheel and sensor on the crank. 2 reasons for this is higher accuracy and disable the ignition if the engine does a kickback. Kickbacks can make quite a large intake explosion depending on the engine setup. I'm just not sure if anyone needs more than 1 degree accuracy. Also MSD's Hall sensors tend to fail without warning from vibration. I also thought about using active IR sensor and reflective tape a crank wheel. Your thoughts?

I ran Yamaha dirt bikes 100cc school-boy class until 15 then 250cc but, by 17 I out weighed most other guys by 15-20 kilos so I gave that up. Raced 250cc snowmobiles for 3 years with my brother and at 18 I just raced cars. Started with 4 bangers and then V8's and haven't looked back, I like the 2.5g acceleration. My dad and a couple of uncles raced Fords on dirt tracks off & on when I was very young back in the late 60's to early 70's, so I guess that's why racing is in my blood. Currently collecting parts for a 496 CID twin turbo 1,000 to 1,200 Hp engine, I need more power LOL, 500 Hp doesn't do it for me anymore.

Ray


----------



## awake

74Sprint said:


> Wife says I can buy a Grizzly all-in-one lathe/mill once we sell the house and down size, can't wait.


Ray, I don't know enough to comment on the ignitions, but did note the above sentence near the end of one of your posts. You probably already know this, but just in case - the style of combo lathe-mill which features a column on one end (e.g., like this: 31" 3/4 HP Combo Lathe/Mill at Grizzly.com) tend to have a pretty poor reputation. Yes, there are better ones and worser ones, and yes, some folks have done some amazing work with one ... but there is no getting around the fact that they are quite a compromise. The combo style which features a more-or-less standard lathe but has the option to mount a mill column behind it (e.g., like this: 8" x 16" Variable-Speed Lathe with Milling Head at Grizzly.com) seem to have a better reputation - still a compromise, but apparently a better one. Generally, however, the advice I have seen over and over again is, if at all possible, get separate machines rather than a combo.

You'll note in the above that I cannot speak from personal experience with any combo machine. I did start out _thinking_ a combo machine would be an economical and practical way to get into machining, but as I read the sort of comments I am reflecting above, I was persuaded to look for separate machines - and so glad I did. In my case, I had the room for separate machines, and I was able to snag a great deal on a full-sized lathe and a small import mill for a total of around $1000. Later I added a Bridgeport mill that I was able to buy for $1500, and I put another couple hundred into parts to refurbish the VS head on the mill (a pretty standard thing to have to do), and maybe 50 dollars in parts to put together an RPC from a scrap motor I was able to pick up for free. Along the way I also stumbled on a mini-lathe (7x14) for a mere $50, but that was a once-in-a-lifetime deal, not the sort of thing I would ever expect to see again. Bottom line: for less than the cost of a decent quality combo machine, I have two lathes and two mills, one of each of which has far more capacity than most combo machines. The flexibility that comes with having independent machines, and more than one of each, is beyond fabulous. To be fair, the two full sized machines (one lathe, one mill) that I have are well used "old iron," which has pluses and minuses ... but they have served me well.

None of this may be applicable to your situation, particularly if room is tight for independent or full-sized machines - but hopefully it is useful as one data point as you consider what to buy.


----------



## bluejets

Hi Ray,
            Ok, get the encoder idea and imagine simply an encoder wheel on say the cam shaft.
I think magnetic would be a much better approach than any form of IR for obvious reasons, still you could try and see how it goes.
High precision or extras such as kick back protection I imagine to be unnecessary and would possibly be a source of headache but you could have it as an alternative I suppose. With most of these engines here, as long as they start easily, run reasonably well ( some are shockers) and are maintenance free to an extent, most as happy as a pig in ***.
Talking of maintenance, had to do one of my old boat motors recently (Neptune boat) . Popped it on here for a laugh..... it used to be on spark with points but changed back to "racing fuel"  ................... 
The KISS approach usually wins in model gear at least. 

Know what you mean about the HP never being enough however, the second 250 Yamaha was if I remember correctly a YZ250G 6 speed. It belonged originally to a bloke who came in at around 16 stone and bike was only a few months old so a suspension rebuild had to be done. That along with a new ring (only one on the piston) and it was a real handful. Taught me a lot of respect for little ole' 250.  Look up after being bucked off to see Dad shaking his head.


----------



## 74Sprint

The second lathe/mill combo you linked to is the one I was thinking of. I know a fellow racer that has that one and like you said it's not the greatest but it does most of his work. He does have an old lathe, I can't recall off hand the brand but it does have a 6 foot bed, quite a bit larger than I would ever use. Most of the lathes around here that I see come up for sale are usually for wood or industrial size. But I have some time yet before I need equipment. The YZ250G 6 speed is the one I had, scared the crap out of me the first time I tried it going full bore. I sold it after I came off a jump wrong and hit a tree, the tree won LOL. I then bought a Honda XL250 and just rode on the street and some trails. Ah life goes on.

Neat little engine you got there.
Ray


----------



## 74Sprint

I was thinking after reading several posts here and on other web sites; “what is the very simplest ignition board that I can come up with that can be used by points, Hall-Effect, and inductive pickups and have adjustable dwell so it can be used with different coils”. So I came up with this below and see attachments.

Simplest Sparky:

Any comments?

Ray


----------



## scottyp

Just glancing at it, I like it.  It's clear, concise, flexible and well documented! Just stating the obvious -


----------



## CFLBob

I'll go one step farther, it seems enormously flexible and looks like it could be very useful for all of us.  Useful on many kinds of model engine.


----------



## ozzie46

74Sprint said:


> I was thinking after reading several posts here and on other web sites; “what is the very simplest ignition board that I can come up with that can be used by points, Hall-Effect, and inductive pickups and have adjustable dwell so it can be used with different coils”. So I came up with this below and see attachments.
> 
> Simplest Sparky:
> 
> Any comments?
> 
> RayView attachment 128053
> View attachment 128054


Would this work on a v-8 (hall effect)?


----------



## 74Sprint

scottyp said:


> Just glancing at it, I like it.  It's clear, concise, flexible and well documented! Just stating the obvious -


thank you

Ray


----------



## 74Sprint

CFLBob said:


> I'll go one step farther, it seems enormously flexible and looks like it could be very useful for all of us.  Useful on many kinds of model engine.


Thank you, that was my intentions.

Ray


----------



## 74Sprint

ozzie46 said:


> Would this work on a v-8 (hall effect)?


Are you talking about the Hall-effect that GM uses with it's window dizzy? If so, I don't see why not so long as the signal-in meets the voltage requirement.

- The CD4047B needs an input signal of at least 3.5 volts when running on 5 volts. 7 volt input signal when running on 10 volts and 11 volt input when running on 15 volts. This would be either positive or negative going.

Ray


----------



## 74Sprint

I just got a bunch of parts in to make ignitions and parts for testing. I have a few 2 stroke engines I can play with including batteries from 4.7 to 12.5 volt. I'll post my results here. But I have one job to finish first, a automotive 2 relay & 4 relay programmable cooling controller.

Ray


----------



## dsage

Ray:
LED1 is never going to light
The voltage at the base of the transistor will never go above 0.7v. The led will require at least a couple of volts. Unless you have something going on with a negative supply at VSS (-) on the led cathode?  But I don't see it on the schematic.


----------



## dsage

Ray:
If you simply choose to use the Q(not) output of the chip (instead of the Q output) the transistor (and coil) will be energized most of the time instead of off most of the time. (sort of an inverted dwell scenerio). That's going to be an awful load on the transistor and coil and a waste of power for no reason. Maybe I'm not getting your reason for that option.


----------



## dsage

Ray:
You show an option for an IGBT transistor for Q2. I don't see a Q2 in the schematic. Same for TR2.
I assume they are replacements for Q1 and TR1?
TR1(2) being ignition coils I assume.


----------



## ozzie46

74Sprint said:


> Are you talking about the Hall-effect that GM uses with it's window dizzy? If so, I don't see why not so long as the signal-in meets the voltage requirement.
> 
> - The CD4047B needs an input signal of at least 3.5 volts when running on 5 volts. 7 volt input signal when running on 10 volts and 11 volt input when running on 15 volts. This would be either positive or negative going.
> 
> Ray


No, a model V-8 Think Lil Demon V-8.


----------



## 74Sprint

dsage said:


> Ray:
> LED1 is never going to light
> The voltage at the base of the transistor will never go above 0.7v. The led will require at least a couple of volts. Unless you have something going on with a negative supply at VSS (-) on the led cathode?  But I don't see it on the schematic.


Your right I missed that one my bad. I'll fix it up.



dsage said:


> Ray:
> If you simply choose to use the Q(not) output of the chip (instead of the Q output) the transistor (and coil) will be energized most of the time instead of off most of the time. (sort of an inverted dwell scenerio). That's going to be an awful load on the transistor and coil and a waste of power for no reason. Maybe I'm not getting your reason for that option.


I haven't chosen a PNP yet but as I stated in the write up I still have testing to do and will let people know what I find. Including the parts I have tested.



dsage said:


> Ray:
> You show an option for an IGBT transistor for Q2. I don't see a Q2 in the schematic. Same for TR2.
> I assume they are replacements for Q1 and TR1?
> TR1(2) being ignition coils I assume.


Yup, my software wants to sequentially number everything a PITA. I can make things like part 1.1, 1.2 etc. so I'm just going to delete the part reference and use a text box.

I'll post the corrections, thanx dsage.

Ray


----------



## 74Sprint

ozzie46 said:


> No, a model V-8 Think Lil Demon V-8.


Yes but how are you going to direct the spark? are you going to use a dizzy? A crank trigger?

On my race car I'm going to use both a crank trigger to fire and a dizzy to distribute spark at first. From this I while end up using a shift register to use coil near plug and 8 coils along with a Ford 302 cam sensor.

Ray


----------



## dsage

Ray:
Q1 only has a dc current gain (hfe) of 8 at 5 amps collector current. Therefore it's going to require about 600ma of base drive current to properly drive the coil.
The CD4047 at  best will supply only 6ma. You're going to need at least a couple of pre-drive transistors.

How about this:
As you suggested. Go back and re-design your circuit, test it thoroughly and THEN present it. And make us a video of it working.


----------



## ozzie46

74Sprint said:


> Yes but how are you going to direct the spark? are you going to use a dizzy? A crank trigger?
> 
> On my race car I'm going to use both a crank trigger to fire and a dizzy to distribute spark at first. From this I while end up using a shift register to use coil near plug and 8 coils along with a Ford 302 cam sensor.
> 
> Ray



Dizzy. At the moment I'm using dsages electronics. which is working well.
Ron


----------



## 74Sprint

dsage said:


> Ray:
> Q1 only has a dc current gain (hfe) of 8 at 5 amps collector current. Therefore it's going to require about 600ma of base drive current to properly drive the coil.
> The CD4047 at  best will supply only 6ma. You're going to need at least a couple of pre-drive transistors.
> And BTW. You can't drive the coil high with a PNP transistor. It will require a base voltage higher than the supply to turn on properly.
> How about this:
> As you suggested. Go back and re-design your circuit, test it thoroughly and THEN present it. And make us a video of it working.


LOL I'm trying.

Ray


----------



## 74Sprint

dsage said:


> Ray:
> How about this:
> As you suggested. Go back and re-design your circuit, test it thoroughly and THEN present it. And make us a video of it working.


That's not what I'm trying to accomplish here. What I'm trying to show is the problems one would encounter if they tried to make an ignition on their own with using basic tools like just a multi-meter. I could very easily simulate a circuit using a spice program and get very close to a fully working ignition. If people here want to see that then I could do that also. But what would they learn? Advanced skills? I like this web site because there are people who show their trials and tribulations as they learn to create things from metal, working engines. There are also master machinist here with more knowledge of machining metal than I could possibly learn on my own. I believe "it's not the destination that matters, it's the journey that matters". Show me a completed engine and what did I learn, nothing, what did someone teach me, nothing.

Yes I will go back and redesign my circuit but, I will not finish a working example and display it here. I'll lay it all out for everyone to see as I trip and stumble.
Now the transistor I first decided to use will not work properly. I had a bunch left over from repairing an LED scoreboard and decided what the heck I'll give them a try. Well the CS4047 can put out a signal strong enough to turn on the PHE13007,127 but not fully but, why?
It turns out that the little power supply that I was using has output current overload protection and as soon as the transistor tried to turn on, the power supply turned off. My proper or good power supply decided to show it's age and needs repair. So I got out a 11.7 volt lithium battery 20C and tried that with no protection, well that cooked the coil I was using, LOL. I just went through the transistor to the coil. It's the old Ohms law kicking in. Voltage(E) / Resistance(R) = Current(A) let's make that magic smoke with 20 amps, LOL.

The CD4047 is working just as I predicted which, was nice. As for a transistor, IGBT, or MOSFET I'll have to see what I have and that is a lot. As I check what I have I'll check the specs and update my new inventory database.
R&D (Research & Destruction) 

Cheers
Ray


----------



## 74Sprint

I would like to point out that desage is correct about the PHE13007,127 transistor and the base current. It takes .550 amps to fully turn it on, not good. I'll have to see what else I have.

I'm waiting for parts to arrive from China so I have some time to kill so I'll do some tech writing.

Also I have been following another thread model-engine-cdi-easy-and-cheap, and it works. The cheapest setup, sort of setup, cost US $12.32 with free shipping to Canada. This includes a 4 pin 12 volt DC CDI box and an ignition coil to go with it. I also ordered a GY6 ignition coil. My orders should arrive early September to November 12, ah nuts. Because it is so cheap to make work for most engines used here I decided to either drop or redevelop some of my ignitions. The ignition coils I had made are for CDI ignitions only, need 100 volts pulsed DC to work.

Coils:
My next problem; Almost all the ignition coils I have are for CDI setups and for hi-performance automotive use, 10 amps and up. The coils used with these ignition boxes range in price between $100 to $200 each. I do have 2 Accel coils but they are old 12 volt type, mainly for points use and 1 Mallory magneto (transformer) coil. So this brings me to "what is the difference between a CDI coil and a regular coil ?"
Well CDI coils come wound in 2 ways, usually. They are what I call the stacked approach and the laminate co-wound coil with 1 layer on top of the other. My coils have 6 stacks.





Then there are the laminate co-wound coils. Notice the stacks of secondary windings! non-CDI.










Now some coils depending on how they are wound can work for both CDI and IDI (Inductive discharge ignition). but generally not recommended. Those Accel coils I have, have a low resistance primary (0.7 ohms) for points and are notorious for burning out points as would any true CDI coil with points. So why do CDI ignitions use such a low primary resistance coil? Well it has to do with the C, L, R time constants. Capacitance, Inductance, and Resistance time constants. Basically it means that the voltage leads the current in a purely inductive circuit by 90 degrees. But the wire resistance will slow down the charging and discharging of the coil, so the lower the resistance the faster the capacitor can discharge through the coil creating a current surge. But you can't have it too low of inductance or the magnetic field (flux) will be too small. Capacitors have ESR resistance that will change it's time constant. The capacitance is from the coil windings and of coarse the charge cap, each laminated coil winding also creates a capacitor. The capacitance has 2 effects, the first is the time constant for the charge cap which has a charge and discharge time constant. Too big of charge capacitor and it will not fully charge between ignition firings, use to small of cap and you won't get enough energy stored. It is usually quicker to charge a cap than it is to discharge it through a coil. The second effect has to do with resonance and impedance. At resonance the CLR circuit will have the least amount of impedance at a certain frequency, on GM's big 4 wire HEI distributor this occurs between 2,400 rpm and 3,00 rpm on my test bench.. At max impedance the circuit will have the most resistance to current flow. With GM's big 4 wire HEI distributor this occurs between 5,500 rpm and 5,800 rpm on my test bench. This is a well know problem with GM performance people.

So what else is different with the 2, well CDI usually almost all the time have less inductance on their primaries but, both can have the same secondary inductance. I find that the Chinese small motorbike coils and such can work with both CDI & IDI ignitions. You'll also find both coils can have the same primary to secondary coil winding ratios 100:1! The difference between the 2 is the CDI charges the primary with usually between 220 - 350 volts and MSD charges to 540-560 volts. I charge mine to 1,100 volts! So why does a IDI put out between 35K & 45K volts and with most CDI putting out @ 55K. Shouldn't the CDI put out a lot more?  Considering they can have the same winding ratio and the CDI having such high voltage on the primaries.

Well yes it should but, ignition coils don't work like that. If I can find it I will post a research paper on 'ignition in a IC engine'. Anyway the gist of it says and I agree with it, that you need high voltage to create an arc to break down the resistance of the gases and vapors from the ground to the electrode. Once this occurs the resistance from the ground to the electrode becomes a short across the secondary winding. Now when this happens the energy can't be destroyed so it gets turned into current, just what we need to burn something between the ground and the electrode. So the CDI does putout more energy for a single spark. Which is why they usually rate them in joules of energy.

Which coil to use for general usage?
For Inductive Discharge:
For points and transistor and not CDI:
Example generally; Primary    0.7 - 1.5 ohm & 4 - 16mH,  Secondary 8 - 12.5K ohm, 37 - 50H  & 70:1 to 100:1 ratio.

For CDI ignitions:
Problem with CD ignitions is at idle they have their highest voltage across the primaries, as the RPM goes up there is less time to charge the capacitor and the output voltage starts to drop. Remember the whole idea of a CDI is high voltage output that gets converted to current. I have found that most CDIs quit sparking when the primary voltage is between 100 to 120 volts DC across the primary.
Example generally; Primary 0.1 - 0.4 ohm & 0.112mH - 1.540mH, Secondary 771.0 ohm - 3.80K ohms generally below 1k ohm & 0.922H - 6.64H.
As you can see, the primaries are pretty close to being the same but, the secondary can vary quite a bit.

NOTE: Inductive coils can work with CD ignition boxes but, CDI coils should not be used with an inductive discharge ignition box, something will make magic smoke. If you want to make your own coil here is a pretty good tutorial DIY Ignition Coil. You can also search the web for others. There are programs on the internet that will make the calculations for voltage, current, wire size, and induction but, most are for just transformers which is what an ignition coil is anyway.

I should also note that some ignition boxes will not work with non-resistance plug wires or plugs, too much EMI noise. One needs to test their ignition box.

Well that's about it.

Ray


----------



## stevehuckss396

Thanks for all that ray. I will need to read it a few more times before it sinks in. Thanks for posting. Much appreciated.


----------



## willray

74Sprint said:


> Basically it means that the current leads the voltage in a purely inductive circuit by 90 degrees.



I'm sure it's just a typo but, that's backwards....  Current lags voltage by 90deg in a purely inductive circuit.  Current leads voltage in a purely capacitive circuit...


----------



## 74Sprint

stevehuckss396 said:


> Thanks for all that ray. I will need to read it a few more times before it sinks in. Thanks for posting. Much appreciated.


Thank you



willray said:


> I'm sure it's just a typo but, that's backwards....  Current lags voltage by 90deg in a purely Inductive circuit.  Current leads voltage in a purely capacitive circuit...


Yup, thanks for pointing that out and I will correct. More on this below.

Because "ELI the ICE man" ELI - Voltage(E) leads Current(I) by 90 degrees in a purely Inductive circuit. ICE Current(I) leads Voltage(E) by 90 degrees in a purely Capacitive circuit. When you think about it on a coil (inductor) what are you creating/storing? - Magnet flux, which can only be created by current flowing through a wire, so your storing current where as a capacitor is storing voltage. Don't forget your dealing with wire and with very little resistance so the max voltage is there pretty much right away. Forget about impedance for now. The magnetic flux wants to collapse all the time, this is the resistance to the current building up a magnetic field. So long as there is constant current flow the field will eventually build. How big it builds is dependent on the number of coil, wire size, voltage pushing that current, and the amount of current available. In a capacitor it takes time to build up the voltage but the max current is right there and as the voltage builds up the current flow decreases. There are ways to calculate these functions by way of time constants, how fast the coil & capacitor can charge and discharge. Also the best way I can think of to illustrate this is a AC induction motor with a starting capacitor. motor-starting-capacitor

Here are some links about "ELI the ICE man".
Phase Difference
www.electrical4u.com

Ray


----------



## 74Sprint

Today I'm going to fix my power supply problem by converting an ATX computer power supply. As I mentioned earlier my old faithful power supply I made when I was a private TQ4 died. I wouldn't mind fixing it for old time sake but, I can build something bigger and better today. I have a bunch of power supplies from wrecked/gutted computers so I might as well use them. The ATX power supply has all the voltages that I need (3.3, 5, 12) with plenty of current. My current little power supply that I have been using can't putout enough current for the coils and even though it says it can it can't and I'm getting voltage droop or over current shut downs, it's a ZK-J3X.






It's nice for low power stuff and it has constant current and constant voltage adjustments, besides other little features.

To build the ATX bench power supply I'm going to follow a build off one of the channels I follow. The fellow that runs the dronebot workshop has some pretty good tutorials and stuff, actually a lot of stuff. Everything from simple circuits to programming micro-controllers. I have the meters needed to complete the build on order but, I can still work with the ATX power supply with out them. The ATX power supply can take in either 120 or 220 volt and has a 550 watt capacity which should good for most of my builds. I also have 350 watt supplies which, would work but, what the heck go big or go home.  I'll let you know how it turns out.

The links:
ATX-bench-supply html
ATX-bench-supply PDF
ATX-bench-supply YouTube

Ray


----------



## 74Sprint

Well lots to talk about today.
First I want to say I broke some golden rules when doing R&D.
1. Don't work on things if your tired.
2. Don't let the grandkids bother you while working (Distractions.)
3. Don't be in a rush.
4. Do the math first.

So on Friday I received a CDI ignition and coil from China like the ones on the model-engine-cdi-easy-and-cheap thread. Problem is the CGI box they sent me is a 5 pin AC instead of a 4 pin DC. I'm still going to try it later with DC when the other coils arrive. I also found a FDP8433 MOSFET, and after checking the specs decided to use it. It is a N-Channel PowerTrench MOSFET 40V, 80A, 3.5mΩ with gate voltage from 4.5v - 10v pulse capable of 1,500 amps. So I would like to say that my circuit works but, with a few small bugs.

So being in a rush and the grandkids wanting to see what I'm doing I forgot to change the dwell capacitor back from a 1uf to a 0.1uf. So the dwell pulse was 10X wider than it should have been. I used the 1uf cap so it would be easier for my meter to show peak values. I measured the resistance and inductance of the coil fields and decided that 1.2k primary should be fine with the +12volt 15amp supply ATX power supply. Ding ding ding, wrong, it should have 10ma but, remember what I said about time constants? In the first time constant the primary coil will look like a dead short almost. This is called current inrush. Voltage is instantaneous and current will fall to 10ma once the coil is charged. So what happened? Well the coil fired 3 times but, then out of the corner of my eye I saw a spark where it should not have been, the coil quit sparking after that. No magic smoke but I also noticed that the ATX power supply was shut down. So started checking everything and I found that the secondary coil was shorted to ground and the case had burst.





Well that sucked, brand new coil only had it for 1 day & 3 sparks, damn R&D.  
As I mentioned inductors will draw as much current as they can get. On GM/EDM locomotives use 2 48 volt starters along with 8 - 8 volt batteries with over 2,000 amps of true cranking power. There is a warning sticker by the start station that warns you not to crank the engine for more than 20 seconds and then wait about 15 minutes before trying again. Well some people are impatient and crank it for too long and the starter motors catch on fire. You would think they would put some sort of device to keep the starter motors from catching on fire.

Anyway, I still have my Accel coils and a new GY6 coil coming. Once I get the rest of my power supply parts I'm going to put current limiting circuits in it for all voltages.
The nice part is, the circuit works just as I planned well very close, I had to add a 220 ohm resistor to drive the MOSFET properly.

Ray


----------



## 74Sprint

Ok, the next thing that is bugging me is the Hall-Effect/s that people are using and how they use them. I'm not going to go into great detail about how Hall-Effects work, you can do that yourself. Oh, only use a switching Hall-effect, unless your really big into electronics.

When working with Hall-effects there are 4 things you need to pay attention too.
1. working voltage.
2. The Bo & Bp points, sometimes listed as (Bops & Brps.
3. The gauss required.
4. Current operating limit.

1. Make sure that the working voltage (max voltage) is well above the voltage you intend to use. And the lower turn on voltage is 2 volts below your power supply/Battery voltage. Simple right!

2.  The Bp & Bo points are the points that the Hall-effect will operate at. In other words the Bo point is the value in gauss that the Hall-effect will turn on. The Bp is the value in gauss that the Hall-effect will turn off. These are import because they tell you the minimum strength of the magnet you need to use. They can also if you have the right equipment to tell you the minimum distance between the magnet and the Hall-effect. The distance between the magnet and the Hall-effect and the strength of the magnet will affect your ignition timing. Lets say the you line up the Hall-effect and magnet at say 8 degrees BTDC and you used the LED to do this and then you ran the engine. So you check the timing with a light but now you see that the timing is at 12 degrees, what the heck! What happened?

Well that LED is more of a trigger indication than a timing light. Now you and me included when we eyeball something we are not very precise. If you look at the Hall-effect datasheet you will see just how fast they are and precise. If the magnet is too strong our the Bo too low then the Hall-effect will turn on before the magnet even gets over the Hall-effect. To correct this you will need to move either the magnet or Hall-effect further way from each other. In some cases this can be over an inch/25mm. In some circuits the hysteresis or the difference between Bo & Bp points are used as the dwell and can be too much or too little, usually with a pnp transistor. Usually Hall-effects when they turn on the signal out goes to ground. So to set this up properly you would have to move the components away from each other or change the magnet and/or Hall-effect or use a different circuit. Of course you can also use to weak of magnet or too high of Bo gauss and it just won't work.

3. So how much gauss do I need? Good question. I'll start by saying that every Hall-effect datasheet I looked at has the test conditions listed. But this still doesn't say what size of magnet and the distance. The places I buy my magnets from always have the strength in Tesla's listed which, is a good start. Magnets aren't listed in gauss instead they use Tesla's. There is a way to help with selecting a magnet and Hall-effect by using an online calculator but, you will need all the specs of the magnet you are going to use beforehand. It is on the Infineon web site Magnet to Strength Calculator. The conversion between gauss and tesla's is an easy one: 1 tesla = 10,000 gauss or (1mT=10 Gauss).
The effects of the magnet can also be changed depending on if the magnet is imbedded in iron/steel or aluminum, or just glued to the surface. One alternative is to use a steel blocker with windows that rotates between the magnet and Hall-effect. Other than this the only thing I can say is don't make anything permanent and just do trial & error. So using rare-earth magnets usually are not the best choice, use cheaper magnets instead if possible.

4. The current operating limit is important and depends on how your going to use the Hall-effect in a circuit. First off don't try and use the Hall-effect to drive the coil directly, you will usually make smoke. Most of the Hall-effects I use are good for 20ma and are used in digital style circuits, high/low stuff. Even trying to do what I did with my first transistor. The CD4047 couldn't put out enough current to turn on the transistor, well it was just barely turning on. So match the Hall-effect current rating to the base/gate current of the transistor you want to use.

I did a write-up somewhere on this forum on different ways one can use a Hall-effect, check it out. I have a bunch of different Hall-effects I need to check out. 

Cheers
Ray


----------



## willray

74Sprint said:


> remember what I said about time constants? In the first time constant the primary coil will look like a dead short almost. This is called current inrush. Voltage is instantaneous and current will fall to 10ma once the coil is charged.



Would you mind explaining exactly what you mean here?   I've seen more than a few people mention "inrush current" with inductors (coils), but inductors display the antithesis of inrush current.

Inductors resist rapid changes in current, generating EMF that "tries" to keep di/dt small.  They don't look at all like dead shorts when initially connected to voltage.  Instead they look a lot like open circuits.   It's capacitors that look like dead shorts.

All that being said, you seem to know your way around electronics, so I have to assume that you're talking about a real physical phenomenon that is unrelated to simple coiled-conductor inductance, but I'm not sufficiently familiar with the actual physical construction of ignition coils to know what that might be. Core permeability/saturation issues?  Something completely different?  If you wouldn't mind expanding on your explanation, I'd appreciate a better understanding of what's actually going on.

Will Ray


----------



## 74Sprint

willray said:


> Would you mind explaining exactly what you mean here?   I've seen more than a few people mention "inrush current" with inductors (coils), but inductors display the antithesis of inrush current.
> 
> Inductors resist rapid changes in current, generating EMF that "tries" to keep di/dt small.  They don't look at all like dead shorts when initially connected to voltage.  Instead they look a lot like open circuits.   It's capacitors that look like dead shorts.
> 
> All that being said, you seem to know your way around electronics, so I have to assume that you're talking about a real physical phenomenon that is unrelated to simple coiled-conductor inductance, but I'm not sufficiently familiar with the actual physical construction of ignition coils to know what that might be. Core permeability/saturation issues?  Something completely different?  If you wouldn't mind expanding on your explanation, I'd appreciate a better understanding of what's actually going on.
> 
> Will Ray


Sure, but I must first apologize because I have a bad habit of jumping ahead and thinking that others are following. Your thinking of the di/dt is correct for a simple coil. Well to start the formula for time constants for inductors is for open air inductors and not for cored ones. The type and construction of core material can change the characteristics of how the coil reacts. Also by now you would think that they would have a global standard when calculating inductance. Some use 50hz, some use 100hz, and some even use 1khz or more. But the good manufactures will state the frequency used to give you a better picture. Anyway, the core is there to concentrate the flux and improve the flux of the coil. I'm building this up, so stay with me. Next the we have a primary coil wound over the core and the core strengths it's field. We then have a secondary winding on top of that which should be in phase as the magnetic field builds outward. Now if you remember Lenz’s law 'the change in current changes flux, inducing an EMF opposing the change'. So you can't have back EMF until you have a change in current first and this includes charging up a coil. Next, the greatest change in current flow happens in the first time constant 63.2% .

Side Note: Some electronic devices are sensitive to the rate of change, especially those huge capacitors for battery backups. They can be damaged if the force (joules) of change is too great for them to handle.

So going by Lenz’s law you would think that the back EMF would slow down the current change the most in the first time constant but it doesn't because the magnetic field is lagging the current change and IMHO it is because of the iron core. I have seen air cores work exactly the way Lenz’s law states. If you look at a series wound DC motor as compared to an AC motor, the DC motor has a lot more torque at start than an AC motor has. If you take Lenz’s law at face value then the DC motor should work just like an AC motor but, it doesn't. If we throw in Faraday’s Law you would have to say that this back EMF is instantaneous but, this starts to become a chicken & egg thing. If we are talking about just DC current then yes the greatest total amount of current flow will be in TC6, we only use 5 though. But in TC5 the current change is very little and the back EMF is at it's greatest because the magnetic field is greatest. Yes I know they say the back EMF is based on change but, that big magnetic field wants to collapse and it is the current holding it out there, just like a solenoid. But the 2 are fighting each other. So what you may have been taught is most likely correct. I really hope I'm not confusing you. But I'm talking about the rate of change in TC1 in a DC situation.

So what happened to my ignition coil? Remember what I said about iron cores and how the ignition coil was wound? Okay, ignition coils can fire twice, once when charging and once when discharging. See European Patent EP1298320A2 below a major screw up by STMicro by patenting it and charging licensing fees. Because the back EMF follows the current flow and not the other way around and when using DC, an inductor will take as much current as it can get. I basically overloaded the insulation between the windings because as the coil was discharging when I hit it with current again. So instead of 12 volts across the primary coil there was more and the magnetic field built up higher than the secondary could handle and shorted out, blowing the coil. In fact some coils used in racing are rated for their max output voltage because their insulation breaks down at that voltage. I have a Crane racing CDI coil with a max 65,000 volts output which is ok with a MSD 490 volt CDI but, not an MSD 8 CDI with 590 volt primary voltage. Also if I had used a 12 volt car battery the coil may have survived because batteries have internal resistance which would have slowed the charge up.

In rush current is mostly related to capacitors charging than inductors charging but it is that first time constant that is in-rush current. The most extreme example of in-rush current I have seen is when we use to start diesel locomotives with a DC welder wired up to 550 volts and 76 volts out. When you hit the starter those 1" inch cables literally jump about 6" off the floor and back down. Now according what you and I were taught those cables should not have jumped until full current is built up but, that's were the formula's & laws fail. According to the laws current should start off low and gradually build up which, is correct. But If you go by the graphs and calculations it is correct to say max current flow in an inductor and max voltage in a capacitor occurs at the end of TC5 but, the biggest change of both current and voltage occurs in TC1, the in-rush.

I have argued with electrical and electronic engineers about the effect of turning the current back on as a coil is discharging and the extra push of current but, they say because of Lenz's & Faraday's laws it's impossible. The effect of back EMF would be pushing current in the opposite direction, guess they never pulled a plug out of a wall socket. We are still discovering things today about things we thought we knew. Who knows maybe one day I'll prove my theory. Having worked with RADAR I learned a lot about resonance and impedance.

Cheers
Ray

P.S. AC locomotives that I have worked on get the AC motors to give more starting torque(punch), at least the ones I worked on by clipping the top of the AC signal and using that to give the AC motors more kick, it gets hammered. It's like a dimmer switch but used backwards. On DC locomotives they start off in series-parallel until the back EMF gets to high, they then make what is called forward transition and going full parallel lowering the overall resistance(Xlr) of the traction motors which lowers the back EMF and they can go faster. There is no need for AC locomotives to make transition.


----------



## Steamchick

Wow! - I'm boggled! - I manage simple coil and points ignition, but reading this maybe I'll stick to steam engines? ....
I thought I understood some of it - like WillRay's query:
_"Would you mind explaining exactly what you mean here? I've seen more than a few people mention "inrush current" with inductors (coils), but inductors display the antithesis of inrush current.

Inductors resist rapid changes in current, generating EMF that "tries" to keep di/dt small. They don't look at all like dead shorts when initially connected to voltage. Instead they look a lot like open circuits. It's capacitors that look like dead shorts."_

But Ray, You sound like my revered hero, Mr. Tesla! Except I can't really follow your explanations... (I have no experience or knowledge of these things - so who am I to judge?).
But sounds interesting, even if I don't understand the words...
K2


----------



## willray

74Sprint said:


> Sure, but I must first apologize because I have a bad habit of jumping ahead and thinking that others are following.



Thanks Ray,

It'll take me some time to parse and digest your response, but I want to really thank you for not taking the question the wrong way.

Professionally I am occasionally a physicist, so I'm familiar with the definitions and behaviors of the idealized components (though my physics is rather distant from this, so I do have to work for it).  However, I'm woefully undereducated regarding both the typical physical implementation of things like ignition coils, and of the practical application of the idealized models to their less-ideal physical counterparts.  Couple this with domain-specific languages that repurpose words such that they have subtly different meanings than their fundamental physics definitions, and I'm often uncertain where something lies on the spectrum between confusing-to-me and wrong :-/

You're the first person I've seen mention inrush with inductors, who didn't seem to either be parroting something they read on the interwebs, or making the mistake of thinking that inductors "obviously" have inrush because induction motors or transformers are affected.  I really appreciate you taking the time to try to explain.

As an initial question, and demonstration of my ignorance - it surprises me that ignition coils would be made with susceptible cores.  I would have assumed that a susceptible core would work against the rapid collapse of the field that is desirable for creating the high EMF in the secondary "when the points open".   Is this choice a balancing act between stored energy and rate of field collapse, or, am I misthinking something?

Thanks again,
Will


----------



## Steamchick

Hmmm. More interesting comment... I understood the bit about susceptiblec core... rapid collapse of the field.... 
So am I right in thinking you are effectively tuning the resonance of the primary to be very high frequency, to maximise dI/dt in the primary? And consequently the voltage developed in the secondary? And part of your explanation is that larger inductance leads to lower resonant frequencies....?...
I wonder if using the automotive "coil on plug" would give you a suitable coil .... if you could design the right trigger? There must be thousands of good parts in scrap yards awaiting recycling..... so cheap-to-buy compared to your "3 sparker"?
Or maybe you should ignore my comments as simply wrong? - feedback please... I won't spoil you thread if I am way off understanding this subject...
Thanks
K2


----------



## 74Sprint

Steamchick said:


> Wow! - I'm boggled! - I manage simple coil and points ignition, but reading this maybe I'll stick to steam engines? ....
> I thought I understood some of it - like WillRay's query:
> _"Would you mind explaining exactly what you mean here? I've seen more than a few people mention "inrush current" with inductors (coils), but inductors display the antithesis of inrush current.
> 
> Inductors resist rapid changes in current, generating EMF that "tries" to keep di/dt small. They don't look at all like dead shorts when initially connected to voltage. Instead they look a lot like open circuits. It's capacitors that look like dead shorts."_
> 
> But Ray, You sound like my revered hero, Mr. Tesla! Except I can't really follow your explanations... (I have no experience or knowledge of these things - so who am I to judge?).
> But sounds interesting, even if I don't understand the words...
> K2


LOL, don't worry in electronics engineering school there was quite a few people that had a hard time getting their heads around it.
What you see below is what we were all taught. It shows the charge curve in Blue and the voltage drop across the inductor in Purple. As you can see in the first time constant the current reaches 63% of max flow. Don't worry about the voltage drop for now. Remember this is DC here going from zero to max. And we are working with the change not the max current.






Next, transformers can be wound in many different ways but, for ignition coils they generally use the auto transformer style. This is where one winding is on top of the other and with one end of each coil is tied together and keeping them in phase. Now the voltage drop shown in Purple is basically your back EMF voltage. Remember this is DC so we don't really have to worry about inductive impedance for now. Note: the Purple line can also represent the coils discharge. Next, because the ignition coil is wound auto transformer style anything that happens on the primary also happens on the secondary and in phase. But in simple terms because there is a step-up ratio the current gets converted to voltage, in a step-down it's the voltage that converts to current. Well not all of it but most of it. So in TC1 you get a huge voltage rise/spike in the secondary coil. The current flowing in the secondary is rising at the same rate as the primary and it also sees back EMF because of the change in current flow. Now if the winding ratio is say 100:1 then according to the laws that back EMF is going to be 100 times higher than in the primary. So now we have an inductor that will take as much current as it can get, a power supply with lots of unhindered current, and a 100:1 winding ratio, the back EMF in the secondary got high enough to over come the insulation and short out my ignition coil.

In-rush current, that current flow in TC1, does look like a short to current because TC1 has the greatest change. Every TC after that has less change, just like if someone was increasing the resistance and slowing down the change. Remember that Purple line represents back EMF so when the current reaches a steady state there is no more back EMF. But we still have that magnet field that wants to collapse back onto the primary coil. So lets do a collapse and make a spark. When the magnetic lines of flux collapses back down and cuts through the secondary coil it induces current flow in the secondary which gets turned into a high voltage spike/spark. But that magnetic field also wants to go back to where it was created and that creates a voltage spike in the primary, this is where the ringing effect comes from and shows up on the secondary and can be seen with an oscilloscope.

Let's look at the discharge side of things and we will use points. Current flowing is just like water and according to Newton an object in motion wants to remain in motion. So both current and water flowing is happy until it hits a wall or open circuit point, it piles up and the pressure (voltage) rises up. In the case of current that pile up can raise the voltage so high that it can jump across an opening (points gap). That spark/arc is just like plasma and takes some material with it when it jumps across. To temporarily catch that spark with use a capacitor which is like a short for the current flow, when the points close again that energy is returned to the circuit. But wait, what if we don't use a cap and let the spark happen. Well the high voltage spark is going straight to the primary coil, so now instead of the primary coil being a ground/negative potential it is now at maybe -1000 volts on the negative side and +12 on the other side. Now turn the current back on at just that moment what do you think will happen with current flow instead of having a potential of 0 to +12 volts you now have -1000 to +12 volts. It took me 9 months to figure how to make that one work. Oh that in-rush current can and will blow MOSFETs and IGBTs if the rate of change is to high, some manufacturers list max rate of change.

Cheers
Ray


----------



## 74Sprint

willray said:


> Thanks Ray,
> 
> It'll take me some time to parse and digest your response, but I want to really thank you for not taking the question the wrong way.
> 
> Professionally I am occasionally a physicist, so I'm familiar with the definitions and behaviors of the idealized components (though my physics is rather distant from this, so I do have to work for it).  However, I'm woefully undereducated regarding both the typical physical implementation of things like ignition coils, and of the practical application of the idealized models to their less-ideal physical counterparts.  Couple this with domain-specific languages that repurpose words such that they have subtly different meanings than their fundamental physics definitions, and I'm often uncertain where something lies on the spectrum between confusing-to-me and wrong :-/
> 
> You're the first person I've seen mention inrush with inductors, who didn't seem to either be parroting something they read on the interwebs, or making the mistake of thinking that inductors "obviously" have inrush because induction motors or transformers are affected.  I really appreciate you taking the time to try to explain.
> 
> As an initial question, and demonstration of my ignorance - it surprises me that ignition coils would be made with susceptible cores.  I would have assumed that a susceptible core would work against the rapid collapse of the field that is desirable for creating the high EMF in the secondary "when the points open".   Is this choice a balancing act between stored energy and rate of field collapse, or, am I misthinking something?
> 
> Thanks again,
> Will


Your welcome, no your not miss thinking something, your right it is a balancing act. The best way to think of an ignition coil is to think of them as transformers and not inductors even though they are technically inductors. Everything is a cause and effect so which comes first, what creates the other. I studied deflagration in IC engines, from spark to exhaust and when a cylinder fires the air/fuel mixture doesn't explode right away, it burns first and progresses to an explosion. It doesn't explode first and the burn. Remember that laminate core is there for the primary because it is closest to it so you design for the primary. Also the fields expand past the secondary coil and the core becomes magnetized helping the primary. But when the field collapses it doesn't need any help because it wants to resume it natural state. The only thing that could hinder the collapse would be core that is to large. The remaining magnetic flux would slow down the collapse. Ignition coils still behave according to the laws of physics just slightly modified. Ignition coils still are subject to resonance & impedance frequencies. I find it is the way the 2 coils are coupled that is the main standout from other transformers. In the old days magneto high tension coils were called transformers. Magnetos only create current and no voltage, the magnetos rely on the resistance of the wire in the primary to create the voltage. Not too low and not too high of resistance.

Most of what I talk about comes from experience. 40 years ago when I was in engineering school some of our instructors when they couldn't explain something would say "shut up and take it for what it's worth and besides it works by FM" in other words just except it and it works by F..king Magic. Of course today we understand more about what is going on because of quantum mechanics. Oh I still keep my formula books handy because my mind isn't as good as it used to be. LOL Retired and Retarded they say.

Do you understand what I mean by the greatest change that is allowed looking like a short in TC1 for an inductor? Because of my work with CDI ignitions I can say that capacitors do work like the formulae. But still with caps the current rises very quickly and the then tappers off as the cap charges. The current isn't at max right away it too has a ramp up just that it is done very very quickly. So where did I get all this? Well from RADAR circuits. With RADAR circuits everything has to be taken in to consideration. A run on a circuit board can very quickly turn into an antennae or an inductor, solder pads can become capacitors, board edge connectors are really bad for that. RASARs are almost always pulsed they can go from 0Hz to GHz and 0 watts to Megawatts in a nano-second. You want to talk about weird Sh_t try RADAR.

Oh remember if the current is not changing in a transformer then nothing is happening except current flowing through the primary. I have a question for you "how come physicists don't understand how radio waves travel through space? after all radio waves will not cross a perfect vacuum"

Cheers
Ray


----------



## 74Sprint

Steamchick said:


> Hmmm. More interesting comment... I understood the bit about susceptiblec core... rapid collapse of the field....
> So am I right in thinking you are effectively tuning the resonance of the primary to be very high frequency, to maximise dI/dt in the primary? And consequently the voltage developed in the secondary?


I tune for  resonance of the primary only in my 48 amp ignition. It works by first opening a window so to say, by window I mean that I allow the resonant frequency of the primary through but only for a set time. It works like a tank circuit that gets big time amplified. Also as the RPM goes up the window gets smaller, so at idle it may spark 6 times and at 6,000 RPM only 4 times and each time the spark gets boosted higher and higher per sequence. I have seen the spark go over 100Kv but not by much. Usually the sparkplug fires before that and levels out around 80Kv or it comes out the side of 8.8mm sparkplug wire to ground somewhere. You can't maximize the di/dt in the primary, that value is fixed when the coil is made. The voltage in the secondary or the quality there of is tied to the ignition transformer design and after that it follows what happens in the primary. What I'm actually doing is taking and using what we normally are trying to get rid of by placing a varistor or MOV, same thing or even a diode on a relay, MOSFET, IGBT to clamp the back EMF which can cause a relay or solenoid to chatter and MOFETs or IGBTs to get punch through with an inductive load.



Steamchick said:


> And part of your explanation is that larger inductance leads to lower resonant frequencies....?...


True that is correct but, bare in mind that the core if there is one and it's effectiveness will modify the resonant frequency. 



Steamchick said:


> I wonder if using the automotive "coil on plug" would give you a suitable coil .... if you could design the right trigger? There must be thousands of good parts in scrap yards awaiting recycling..... so cheap-to-buy compared to your "3 sparker"?
> Or maybe you should ignore my comments as simply wrong? - feedback please... I won't spoil you thread if I am way off understanding this subject...
> Thanks
> K2


Have to remember that my China coil blew is mainly I had way to much dwell and just happened to get the timing just right to wack it, my bad luck. Yup I'm going to the auto-wrecker this weekend to get some coils Ford, GM, and Mopar. Either COP or CNP coils. Also GM stand alone coils that were used in the late 80's and early 90's before they went to coil near plug style. These coils have a very high output and are very fussy about the cap and rotor material. A lot of mechanics get fooled by them breaking down and getting spark scatter. No your not far off, also I don't mind the discussion, isn't that what this forum is for. Besides I'll be asking a lot of questions when I finally start making chips.   

Cheers
Ray


----------



## Steamchick

Thanks Ray, This is education for me:
I know the bit about "_deflagration in IC engines, from spark to exhaust and when a cylinder fires the air/fuel mixture doesn't explode right away, it burns first and progresses to an explosion. _( I thought this was the "knocking" pre-ignition condition...)._ It doesn't explode first and then burn._" - as I read a paper on it very recently! = Not what I was taught 5 decades ago - that the spark ignites the fuel air mix with a small explosion (The H and O ions first) as it ionises the molecular mix... followed by a flame front (of HC, C and O2 and N2 molecules) that accelerates to sonic velocity (faster than the pressure rises) until the piston has travelled far enough down the cylinder so the expansion extracts enough energy, or the flame front meets cool gases near metal surfaces, so that the flame front is cooled so the combustion stops (CO stops burning in atmospheric air around 320deg.C. but cylinder pressures are much higher, so combustion "stops" at a different temperature), OR the exhaust valve opens, when further expansion down the exhaust pipe stops the combustion before all the fuel has burned properly.
I did understand that the spark energy (actually voltage?) needs to be adequate to ionise the gas at "compression" pressure in order to "strike" the arc, that then needs enough current to ionise adequate gas to the "molecular temperature" required so the ignition of the gas occurs. I.E. "weak" sparks won't strike the arc, or ignite the fuel-air mix. - Hence, the coil needs to have a secondary winding with very rapid rise of voltage (due to engine speed?), of a high enough voltage and energy so the spark strikes at the plug contacts and stays long enough to ensure correct ignition for a self-sustaining burn of the mixture. (All happening in micro-seconds). 
What I don't really understand is how to trigger the coil primary, nor what sort of impedance is used, to store adequate energy in the "coil charging" phase (contact-breaker dwell?) and release it during the arcing phase (coil discharge). I seems to be a balance between a low impedance for a short "half-life" during charging and discharging, but a high enough impedance to store enough energy for an adequate spark energy to ignite the mixture at all conditions (avoiding mis-fires at higher revs or poor cold-starting, etc.). - A different engineer sorted "ignition" at work. I just had the joy of determining the best commercially practical HT cables... and I gained some small understanding of Radio suppression in the process. (Resistive or inductive HT cable systems).
Thanks for the education,
K2


----------



## Steamchick

Ray: I was taught (in the 1980s) that the coil heating is due to the combined heat from the inrush current (RMS of I-squared-R in the primary during t of contact dwell, plus zero-current during t of contacts open?), plus the "out-rush" current (I-squared-R in the secondary during arc-duration at the spark-plug - this t is very small!). This meant that inductive HT cables (that I selected as most appropriate for our application) actually should have heated the coil more than the (cheaper) resistive HT cables (that the coils had been designed for) but on real testing the temperature increase wasn't measurable. (secondary winding discharge current is in micro-amps for micro-seconds duration). But maybe my memory is in error? - For those that don't know but are interested, but inductive and resistive secondary cables, plug-caps and plugs reduce the peak _current_ of the spark, hence the peak amplitude of the radio frequency noise produced. The voltage of the spark is determined by the breakdown voltage at the spark-plug = An engine parameter, not determined by coils, etc. After the spark strikes, the arc _current_ rises very fast (voltage across the spark-plug contacts falls as the ionised gas resistance drops rapidly). I'm guessing: but I think that how quickly the voltage achieved (just before the arc is generated) determines the maximum frequency of the radio noise (is it dV/dt? = rate of change of voltage?), whereas the arc current (or dI/dt?) determines the "amount" of radio noise emitted. Thus resistors and inductors in the extra bits after the secondary coil help to limit that arc current (reduce dV/dt - hence max I is reduced?) - therefore suppressing radio noise. The HT cables become the antenna for broadcasting the radio noise. (Any radio engineers want to correct this? - or add to the explanation? - It was 40-plus years ago when I was taught this information... but I forget the maths!).
Not machining, but related to "spark ignition engines"...
Cheers!
K2.


----------



## 74Sprint

Steamchick said:


> Thanks Ray, This is education for me:
> I know the bit about "_deflagration in IC engines, from spark to exhaust and when a cylinder fires the air/fuel mixture doesn't explode right away, it burns first and progresses to an explosion. _( I thought this was the "knocking" pre-ignition condition...)._ It doesn't explode first and then burn._" - as I read a paper on it very recently! = Not what I was taught 5 decades ago - that the spark ignites the fuel air mix with a small explosion (The H and O ions first) as it ionises the molecular mix... followed by a flame front (of HC, C and O2 and N2 molecules) that accelerates to sonic velocity (faster than the pressure rises) until the piston has travelled far enough down the cylinder so the expansion extracts enough energy, or the flame front meets cool gases near metal surfaces, so that the flame front is cooled so the combustion stops (CO stops burning in atmospheric air around 320deg.C. but cylinder pressures are much higher, so combustion "stops" at a different temperature), OR the exhaust valve opens, when further expansion down the exhaust pipe stops the combustion before all the fuel has burned properly.
> I did understand that the spark energy (actually voltage?) needs to be adequate to ionise the gas at "compression" pressure in order to "strike" the arc, that then needs enough current to ionise adequate gas to the "molecular temperature" required so the ignition of the gas occurs. I.E. "weak" sparks won't strike the arc, or ignite the fuel-air mix. - Hence, the coil needs to have a secondary winding with very rapid rise of voltage (due to engine speed?), of a high enough voltage and energy so the spark strikes at the plug contacts and stays long enough to ensure correct ignition for a self-sustaining burn of the mixture. (All happening in micro-seconds).
> What I don't really understand is how to trigger the coil primary, nor what sort of impedance is used, to store adequate energy in the "coil charging" phase (contact-breaker dwell?) and release it during the arcing phase (coil discharge). I seems to be a balance between a low impedance for a short "half-life" during charging and discharging, but a high enough impedance to store enough energy for an adequate spark energy to ignite the mixture at all conditions (avoiding mis-fires at higher revs or poor cold-starting, etc.). - A different engineer sorted "ignition" at work. I just had the joy of determining the best commercially practical HT cables... and I gained some small understanding of Radio suppression in the process. (Resistive or inductive HT cable systems).
> Thanks for the education,
> K2


Wow you really know your stuff. One needs to remember that there is no such thing as an explosion right away, at least humanity hasn't found a material that does. I have an old paper somewhere that explains the process of an atomic bomb detonation and even that goes through the deflagration process. 

I have found a lot of people miss use terms and even myth becomes truth. 
For example:
Knock: This is caused by too early of ignition, timing too advanced. What is happening hear is the piston trying to turn the engine backwards. The knock sound is all the oil being hammered out of the clearances such as the rod to crank and crank to block. IMHO this is also what causes main bearing cap walk. I usually see this on engines where a person is trying to get every last bit of as they can out of an engine, that's nuts and big money. But still no explosion.

Pre-ignition: I like this one because people often have it trade places with knock. Pre-ignition only occurs if there is something approaching or is at a temperature that will ignite a air/fuel mixture. This can occur when taking a granny driven car that is all carboned up for a sustained high speed run or using fuels like nitromethane, I've done both. The sparkplugs used in nitro burning automotive engines use some very tough sparkplugs. They are made from harden steel and fancy ceramics. For example setting the gap on these plugs is crazy, you almost need to use some special pliers to open the gap, a simple sparkplug gauge won't do it, at least I can't. But these nice new plugs turn colours and if the tips and ground electrode are burned away a bit then you might have too much timing. If the centre tip is burned away, the ground electrode is half missing, and ceramic is mostly gone then you have too much timing and pre-ignition is occurring. On my racing snowmobile I knew when I was getting pre-ignition because I would get a snapping sound out of the exhaust and if I didn't cut the throttle right away the next thing to happen was a crankcase explosion with a vaporized hole in a piston. Pre-ignition depending on how it occurs in the combustion chamber can have 2 wave fronts that meet and it will sound like either a dull knock under throttle or a rattle when you shut off the engine, this part is known as run-on.

Ping: In all my years of working with IC engines I've only heard this once and yes it sounds just like 'Ping' whenever I gave the car some throttle. It was on my car and I had the wrong plugs, Ford 302.

You got deflagration and spark ignition IMHO almost right, there are a few parts missing. In drag racing at least at divisional & National events after you make a run down the track you have to either right there or on the return road stop and have your car tested. They basically do just weight and fuel. When they check the fuel in your tank they want to know where you got it from first, then they check the colour, check for additives, and then and this is the important part, is the dielectric strength. This will change if there is too much water or additives. Air and fuel both have an electrical resistance. Air is an excellent insulator, we use it on high voltage power lines for example. All hydrocarbon fuels that I'm aware of have an electrical resistance also. Thing is when you combine them and squeeze them their resistance value goes even higher making it more difficult for a spark to go through. One last thing about the air/fuel mix is during deflagration the pressure wave as it travels across the combustion chamber and squeezing the unburnt mix is burning more and more mix increasing the pressure of the wave. This pressure is compressing the unburnt fuel mix so much that when it burns it burns even faster. The pressure increase continues until the mixture does what is considered an explosion. We want that explosion to occur just after the piston passes TDC for max power. Each and every fuel and engine behaves differently. For example with my 455 CID 11:1 Olds engine I can run 36 Degree total timing with 87 octane pump gas but, I can run 38-40 degrees with 100 octane fuel. On my small Chevy with 13.1:1 compression you take 10 degrees off those numbers. On a nitromethane burning engine total timing can be anywhere from 45-60 degrees total timing, usually around 60. In racing we want a fuel that is easy to ignite but, not too easy and we want it to expand a lot and keep the pressure up as long as possible as the piston moves down. Max pressure usually occurs from -5 to -45 degrees, after 90 degrees the piston is moving down, increasing cylinder volume very rapidly and yup or explosion turns back into just a burn. My new roller turbo cam for the 455/496 the exhaust opens at 63.5 degrees BBDC, it's going to be loud without the turbos.  

Yup you want a secondary to develop a high voltage spark as fast as possible to ionize the mixture but, you also want a magnetic field big enough so when the secondary is shorted out from the ionization you get a long lasting burn, almost impossible to have both. 50 years! It's been 45 for me. I was at first against going to HEI but, I'm a convert. I remember when the hot ticket was running a magneto setup LOL. Before I joined the military I was a mechanic tuning BBC corvettes, 2x4 barrel 426 hemis, doing hop-ups on flathead Fords, and such. 

Anyway, trying to decide how to trigger the primary is a good question but not easy to answer because you need to look at the total package. No matter which setup I use it must have very fast switching. For just triggering I prefer Hall-effects with either a transistor/IGBT or a MOSFET. The first 3 things I look at are the switching speed, current capabilities, and the internal resistance. The voltage and coil primary resistance I'm going to use dictates the current handing. Internal resistance and current dictate the heatsink size. The more voltage drop across the switch and the more current the more heatsink I need. The problems: MOSFETs are voltage driven and are susceptible to noise. But they have very little internal resistance and can handle lots of current and GD voltage. Transistors & IGBTs are current driven so they are usually more complex to drive them. But they are better at handling noise. Transistors usually have a higher internal resistance and therefore generate more heat. IGBTs usually need to have their gates driven to ground or even below that to turn them off, there are IGBT drive chips available. I've had some success with driving IGBTs and they can handle a lot of current. On one IGBT circuit I had, I had to add 2n7000 FETs to drive the gates to zero once.

Cheers
Ray


----------



## 74Sprint

Next thing is inductance which is where the magnetic field lives and this is always a toss up and a balancing act thing. There are a few good websites on making ignition coils and I'll try to find some active links. Questions that come up are 'how many Heneries do I need for the primary & secondary? How much current do I need? What voltage? and what wire size do I need or I'm going to use? Solid core or laminate?

The core material is easy, for low tension ignition you can use solid core or laminate low carbon steel, the lower the better. Use laminate low carbon steel for high tension, less stray eddy currents at higher frequencies. For TCIs it's always how much current do I want to use, not so much with CDIs. With CDIs it's always the extra cost and complexity of making a high voltage charging circuit but the coils are easier to figure out. To this day I still can't get a simple Royer oscillator to work, nuts to that . I made a pretty simple high voltage charging circuit that is guarantied to work and when the cap hit 1,000 volts it quits charging and goes into hic-up mode keeping the voltage up. I even had custom CCFL transformers made in China. Shipping was more than the transformers!



For plug wires I always try to use solid/stranded copper core wire and non-resistor sparkplugs. When I found out NGK was going to only make my favorite plug with a resistor I bought a case of non-resistor ones, I should be good for years. Yup I make a lot of EMI but, at the race track nobody cares. On street cars that have stereos in them I prefer the inductor wound ones, they are a bit more but also work better.

Cheers
Ray


----------



## 74Sprint

Steamchick said:


> Ray: I was taught (in the 1980s) that the coil heating is due to the combined heat from the inrush current (RMS of I-squared-R in the primary during t of contact dwell, plus zero-current during t of contacts open?), plus the "out-rush" current (I-squared-R in the secondary during arc-duration at the spark-plug - this t is very small!). This meant that inductive HT cables (that I selected as most appropriate for our application) actually should have heated the coil more than the (cheaper) resistive HT cables (that the coils had been designed for) but on real testing the temperature increase wasn't measurable. (secondary winding discharge current is in micro-amps for micro-seconds duration). But maybe my memory is in error? - For those that don't know but are interested, but inductive and resistive secondary cables, plug-caps and plugs reduce the peak _current_ of the spark, hence the peak amplitude of the radio frequency noise produced. The voltage of the spark is determined by the breakdown voltage at the spark-plug = An engine parameter, not determined by coils, etc. After the spark strikes, the arc _current_ rises very fast (voltage across the spark-plug contacts falls as the ionised gas resistance drops rapidly). I'm guessing: but I think that how quickly the voltage achieved (just before the arc is generated) determines the maximum frequency of the radio noise (is it dV/dt? = rate of change of voltage?), whereas the arc current (or dI/dt?) determines the "amount" of radio noise emitted. Thus resistors and inductors in the extra bits after the secondary coil help to limit that arc current (reduce dV/dt - hence max I is reduced?) - therefore suppressing radio noise. The HT cables become the antenna for broadcasting the radio noise. (Any radio engineers want to correct this? - or add to the explanation? - It was 40-plus years ago when I was taught this information... but I forget the maths!).
> Not machining, but related to "spark ignition engines"...
> Cheers!
> K2.


Your correct for most of what you said. First there is no radio frequency as per say a frequency. The EM pulse covers pretty much all frequencies. When you look at an ignition coil and take the primary first it is not much more than a big electro magnet. You need and want a big magnetic field of stored energy. The field has voltage and current as components, better to think of it as watts or joules. Now when the field collapses and transfers that store energy to the secondary there is some loss but you are still transferring energy. Your just swapping the current for voltage. If we could have a transfer of energy without losses then we would have just as much energy on both sides. Yes your right the current in the secondary is somewhere between mico & milli amps but, the total energy is still close to what you started out with on the primary. In the early days of radio they used spark gap transmitters and Morse code there was no frequency or sinusoidal wave. I believe the Titanic was one of the first ships to use a tunable short-wave radio I maybe wrong.

As far as wires go I did find that the carbon core wires did boost the voltage but only by a very small amount. But the resistive carbon core wires do knock the current down quite a bit, I don't like them. Resistive wires and plugs kill the amount of current flow to reduce the magnetic field (EMI) generated by the sparkplug wires at the cost of the sparkplug gap wattage/joules. I have never seen wires get warm from sparking. Yes the field collapse is drawn out dI/dt longer but with no benefit. However a larger inductance on the secondary side can create a longer dI/dt with benefit. Problem there is if you go too large of inductor you will also slow the field collapse. Everything to do with an ignition coil is a balancing act of trade offs. There is a way around all this but I want to patent it first sorry.

cheers
Ray


----------



## Steamchick

Thanks Ray, Most interesting.
But when you got to talking jargon...." _I was at first against going to HEI (???) but, I'm a convert. I remember when the hot ticket was running a magneto setup LOL. Before I joined the military I was a mechanic tuning BBC corvettes, 2x4 barrel 426 hemis, doing hop-ups on flathead Fords, and such._ " ... - you just lost me there. My English thinks the BBC is the National TV set-up, a Corvette is a small ship used for submarine chasing, a hop-up is some kind of "human" exercise routine... etc.  I never got involved in American Racing stuff. Lotus, Brabham Repco, Williams and Renault a little bit of interest in F1, but mostly British and Japanese motorcycles..... And I avoided Hardly-Able-Twos as agricultural 2-wheeled tractors that people use to make a lot of noise ... We are different sides of the ocean with a different view of life.
On "arc explosions": From my experience with HV electrical design, (400kV circuit breakers) I understand a little about the ionisation and energy transfer - and how the sililar process happens in "exploding chemistry"...
Initially, when an pair of contacts see the electrical field rising, the gases between are a simple insulator. But as the field passes a certain point the gases begin to ionise (corona) and this ionisation  is "hot" - a few thousand degrees - so as the ions take up electrons (cooling and mixing with un-ionised gas) they emit everything from X-rays to long radio waves, including a bit of light. The collapsing hot gas bubbles cause sonic waves - the crackle sound you can hear when HV electrical equipment is discharging corona under extreme conditions.
The ionised gases increase as the voltage goes higher (electic field at the conducting parts increases) until the "cloud" of ionisation becomes a complete conductor. I.E. the resistance of the gas has switched to that of conductance of ions and electrons. Thus the arc strikes. The surge of current as the striking voltage collapses to the "arc-currrent" voltage across the gap has a decay determined by the whole secondary circuit impedance in a coil ignition system. But as the arc current is flowing there is a rapid heating of the gas, ions and electrons so that the positive and negative ions mix and instantaneously combine as chemical combustion takes place: The chemical energy and arc (electrical) energy stuffed into this tiny pocket of ions and gas bheats other gas very rapidly and that heat accelerates the ionisation to strip apart other large molecules (more fuel becoming elemental ions) which add to the chemical re-combination of positive and negative ions with the release of even more heat energy. This is all a spontaneous chemical reaction inside the arc as the plasme heats and chemistry accelerates inside the plasma... This is a true explosion inside the arc, not deflagration. The expanding gases from that (tiny?) explosion inside the arc then forms a ball of combustion as the transition layer of burning gas heats the surrounding cooler gas - and thus the deflagration flame front is initiated. This pressure wave at sub-sonic speed can compress other zones of gases (by the complex reflections and wave interactions) such that other spontaneous explosions take place - this is knocking and the shock waves are detected by modern "knock sensors" (microphones listening for these explosions above a certain amplitude level). And yes, they are heard from the metal of the engine because they travel through the metal and oil films (which do not have time to break-down when a sonic wave passes). But when the human ear can detect these noises above general engine combustion and mechanical noises then the combustion is SERIOUSLY damaging to the engine! All the combustion-related failure modes can occur at levels below the level that we can hear. Hence the reason why (the best and biggest) productioon car companies have very expensive laboratories to research every possible failue mode and elliminate it before selling millions of cars... A happy customer never experiences failures. (A happy customer drives in to the Dealer's garage for a service - then later a new model - rather than getting it towed to the nearest garage and buying a different make!).
Now if a tiny zone of metal (aluminium mostly) is so hot from the general - but localised - engine temperature, (say, in the corner between cylinder head and cyinder wall, next to the gasket?) that spontaneous local combustion occurs from the pressure wave of the main combustion heating the local pocket of gas, then the spontaneous combustion causes a high pressure wave (the knock) followed by a low pressure wave (all the molecules in the local bubble of gas rush away with the explosion leaving a void = vacuum). This local low pressure wave can "hit" the metal surface, which, if hot enough, can cause molecules to be "sucked" off the surface of the metal. (Just like cavitation on a speed-boat propeller). This can give the surface of the metal an appearance of "being chewed by rats", or lots of pin-holes or small cavities. 
As to melting holes in pistons: as they heat-up with "high performance" running - the heat flow from the centre (or hottest zone) of the piston transforms the metal from being lots of crystals bound solidly together, into being  a mix of "metal" and intermolecular "cracks" - between the crystals... I.E. the material is in the transition zone (pre-melting). But this no longer can resist the stresses from the combustion and mechanical pressures so it instantaneously fails.  But there is an interim point - momentarily between the start of failure and destruction, so if the combustion heat is removed just at the right moment, the piston can be deformed, but not failed. You describe this well. I could create this with a Yamahe 350LC engine - with "stage 3 tuning" for production bike racing... I.E. it needed 105~110 octane rated fuel. Actually, it was OK for short blasts at wide-open-Throttle (WOT) at up to 12500rpm... but when sustained at 55mph in top gear (just a piddling 4500rpm) it would overheat the edge of the piston at the exhaust port and the top-land would collapse, trapping the ring and causing a ring-breakage and the piston top-land to crack/break. After 5 pistons, I reduced the overall compresssion (measured using a compression tester at kick-over) from 17.5:1 to 13:1 by inserting an extra head gasket... This allowed me to run on road fuel at 97 octane + Octane booster".
The pistons showed various  stages of failure: The crown showed where the metal had been partly washed-away at the exhaust port, as if by cutting with an oxy-acetylene torch; deformed to trap the ring, parts broken and trapped between the piston and cylinder and sheared-off, etc., so the metallurgucal examination could show the cracks and crystalline aluminium that had been overheated. There was no sound of pinking or knocking when running at a fairly constant 55mph (50~60mph), just a "bang" as the engine seized! This was the case with the first 3 pistons - with varying degrees of damage - but the 4th was not a total failure: I had re-built the engine, checked everything and on a cold day took the bike for a short run at 55mph before stripping to examine the piston = trapped ring from deformed top-land, but nothing broken. Some slight top surface erosion from the exhaust flames, but not as bad as the 3 failed pistons... The 5th piston (after compression reduction) was OK for all running conditions and didn't fail. 
Glad your experience of inductive and resitive HT wires is about the same as my "Theo-rhetorical knowledge"!
Cheers.
K2


----------



## 74Sprint

So what did I get done lately? Well I blew one of my MOSFETs by hooking it up wrong, stupid old eyes and wrong eyeglasses. I played around with the drive circuit of the gate and I am at 6.21 volts. The Vgs(th) voltage gate-to-source threshold (turn on) is 2.8v to an optimum of 10v. I'm taking the gate voltage up in increments to see how things go. Below is the change in the gate driver circuit. The least internal resistance is at 10 volts Vgs(th). D1 & R1 form a voltage divider for the gate voltage, also R1 helps to remove the voltage built up on the gate capacitance for quicker turn off which gives better spark. The CD4047 has no problem driving this kind of circuit. I know I said I wanted to do this without a scope but, I'm having some tuning problems that can only be solved using the scope. So I'm going to have to clean off the other bench and use the scope. Sorry about that. I'll let everyone know what I find.

*OLD*




*NEW*




Cheers
Ray


----------



## 74Sprint

Steamchick said:


> Thanks Ray, Most interesting.
> But when you got to talking jargon...." _I was at first against going to HEI (???) but, I'm a convert. I remember when the hot ticket was running a magneto setup LOL. Before I joined the military I was a mechanic tuning BBC corvettes, 2x4 barrel 426 hemis, doing hop-ups on flathead Fords, and such._ " ... - you just lost me there. My English thinks the BBC is the National TV set-up, a Corvette is a small ship used for submarine chasing, a hop-up is some kind of "human" exercise routine... etc.  I never got involved in American Racing stuff. Lotus, Brabham Repco, Williams and Renault a little bit of interest in F1, but mostly British and Japanese motorcycles..... And I avoided Hardly-Able-Twos as agricultural 2-wheeled tractors that people use to make a lot of noise ... We are different sides of the ocean with a different view of life.
> On "arc explosions": From my experience with HV electrical design, (400kV circuit breakers) I understand a little about the ionisation and energy transfer - and how the sililar process happens in "exploding chemistry"...
> 
> Glad your experience of inductive and resitive HT wires is about the same as my "Theo-rhetorical knowledge"!
> Cheers.
> K2


I have worked on Jaguars, Porsches, Mercedes, Triumphs, Opals, and European Fords like the Capris but, I have a liking to the V12 E-Jags and the little Capris otherwise it's American muscle, the more CID the better, I love torque. My boss at the time belonged to several car clubs, sad to say but, they (car clubs) are almost all gone now. A lot of collector cars that were here have been sold to either the USA or Japanese markets. The only European bikes I have worked on were Triumphs or BSA. I drove Yamahas and Hondas, raced Yamaha dirt bikes along with Ski-Doo and Arctic-Cat snowmobiles with my brother. 

On RADARs we didn't have switch gear but, we did on locomotives and those had solid silver contacts and when they opened under load (1,200V & 2,000Amps) flames and sparks would fly out of the arc chutes and sound like several 12 gauge shotguns going off in the cab. The biggest plasma arc I ever saw was when we had the RADAR in dummy load and something went wrong. Well we had mega-watts of power blow a fist size hole out the side of the  dummy load, scary as hell, good thing the safeties kicked in and shut the RADAR off. As for sparkplugs I wouldn't say the spark is approaching plasma at least with normal ignitions. I have seen what appears to be plasma on a couple of ignitions including my high amp analog ignition. But I think your idea of the plasma during ignition to start the deflagration process is interesting. 

I use to tell people "don't get greedy with the performance, something will blow", well wouldn't you know it I should have listened to myself, I vaporized a hole in the #3 piston on my ACR Neon. I was in a rush and put in regular octane gas instead of high test. In my brothers Arctic-Cat 250cc SxS twin he wanted to try alcohol and nitromethane, well at 10% it's ok, at 20% it's ok and going real good, at 40% it was going like crazy at WOT but, after about 15 seconds the engine just quit. Turns out the top of #1 piston blew off in pieces embedding some in the head and split the engine in 2. The piston looked like a chunk of concrete with no top. In my years of racing I have seen all kinds of things, collapsed ring lands to burst cylinders and probably like you I have lots of stories.

One last thing I wanted to say was, with my high amp analog ignition where there is multiple spark discharges for each firing and where each spark is stronger than the previous one we noticed that the exhaust was much much cleaner. Also we could use less ignition timing and the engine revved up faster. With my scope and probe (home made) I can only measure up to 100Kv and I have seen it go above that in one spark sequence. I made a dummy load (shunt) and measured 1 amp at the sparkplug. Took a hit/poke once from it through my little finger and out my elbow. F..K did that hurt, it threw me back about 6ft and the timing light ended up across the garage. My forearm had a really bad cramp for half an hour and my little finger was numb for 2 hours. My local college has a new advanced automotive research centre which, I am an alumni of, I mean to ask them if I can put a test mule engine on their engine dyno and I'll share my research with them. Otherwise I'll have to buy dyno time.

Anyway cheers
Ray


----------



## Steamchick

Well Ray, Sorry to hear of your shocking experience! 
I hope my explanation of the ignition is somewhere close to what is really happening... it is a compilation of all my varied experiences of "sparks" - and deducing what is happening... 
Curiously, when lightening strikes, the thunder is the sound of the shock wave of the rapid collapse of the fine thread of expanded gas from the arc. And - please correct me if I am wrong? - a plasma is created in every arc where the current flows in the ions? (even in the corona from HV electrical kit). - The ions make-up the plasma (I think?). The temperature of the plasma is easy to see as it is white~blueish... 2000 ~5000 deg.C? I.E. the "visible spark" of light emitted from the electrons leaping to higher energy levels from electrical energy input, then falling back to their earlier lower energy levels while emitting (EMR) radio waves and visible light. (I think a high enough voltage emits X-rays?). And a plasma of ions from air and fuel molecules will explode (spontaneously combust) as the ions re-combine as different molecules (exhaust gases) and release their chemical bonded energy in the process. This is the ignition that starts the flame front that travels in the combustion chamber.
If insufficient arc energy is input, the chemistry of combustion fails... 
In circuit breakers, the arc is generated immediately as contacts separate (incredibly high electrical stress when the gap is near to infinitely small.. well molecular dimensions...) and continues until the voltage reaches zero (as in AC breakers) or adequate arc cooling occurs to prevent a continuous path of ions (plasma) between the contacts: I.E. some resistive gas is put in the place of the conducting plasma. This plasma-cooling and substitution with interposing fluid (resistance) is sometimes generated by external means, and sometimes by a gas explosion generated by the rapid heating of the insulating medium. (e.g. oil or gas).
All good for the soul. Using the body as a conductor is never good for the body or the soul!
Cheers!
K2


----------



## Lagerbolzen

All very interesting life experiences chaps, but could we perhaps keep loosely on the model ignition theme.


----------



## Steamchick

Ooooops! 
(Sorry).
K2


----------



## 74Sprint

Steamchick said:


> Well Ray, Sorry to hear of your shocking experience!
> I hope my explanation of the ignition is somewhere close to what is really happening... it is a compilation of all my varied experiences of "sparks" - and deducing what is happening...
> Curiously, when lightening strikes, the thunder is the sound of the shock wave of the rapid collapse of the fine thread of expanded gas from the arc. And - please correct me if I am wrong? - a plasma is created in every arc where the current flows in the ions? (even in the corona from HV electrical kit). - The ions make-up the plasma (I think?). The temperature of the plasma is easy to see as it is white~blueish... 2000 ~5000 deg.C? I.E. the "visible spark" of light emitted from the electrons leaping to higher energy levels from electrical energy input, then falling back to their earlier lower energy levels while emitting (EMR) radio waves and visible light. (I think a high enough voltage emits X-rays?). And a plasma of ions from air and fuel molecules will explode (spontaneously combust) as the ions re-combine as different molecules (exhaust gases) and release their chemical bonded energy in the process. This is the ignition that starts the flame front that travels in the combustion chamber.
> If insufficient arc energy is input, the chemistry of combustion fails...
> In circuit breakers, the arc is generated immediately as contacts separate (incredibly high electrical stress when the gap is near to infinitely small.. well molecular dimensions...) and continues until the voltage reaches zero (as in AC breakers) or adequate arc cooling occurs to prevent a continuous path of ions (plasma) between the contacts: I.E. some resistive gas is put in the place of the conducting plasma. This plasma-cooling and substitution with interposing fluid (resistance) is sometimes generated by external means, and sometimes by a gas explosion generated by the rapid heating of the insulating medium. (e.g. oil or gas).
> All good for the soul. Using the body as a conductor is never good for the body or the soul!
> Cheers!
> K2


I have found that depending on whom you talk to about plasma you get different answers, everyone has an opinion right. I was taught that plasma is super heated gases at or above 5,000 deg. F. high enough to create free electrons. But if that's the case then what about neon lights and such? In RADAR we used both klystrons (basically a metal tube) & magnetrons (WW2 British invention but finished by MIT) for the final amplifier but, only the klystron becomes radio active because of it's design it produces x-rays from the high voltage.

It's been my experience that the high voltage arc across the sparkplug gap does the ionizing and the current that follows burns the fuel mix in the gap to a plasma. Depending on how much joules of energy in that spark dictates the plasma temperature. The hotter one can make it the better the combustion process will be. I know with my high amp analogue ignition just doing one full load 1/4 mile run the sparkplugs start to show signs of metal transfer from the centre electrode to the ground electrode. I have never seen this transfer with even MSD's 7AL ignition or magnetos. So I am assuming my ignition is creating plasma arcs. I have a circuit schematic and documents about how to make a circuit for measuring the ionization strength/efficiency of a combustion spark when I find it I'll post it. I think if we want to continue this discussion we do it by messaging.  

Anyway, back to the simple ignition. My free time has been dwindling down but, I'm trying to get things done. I bought a portable 2 channel scope kit I would like to finish and show people a inexpensive tool/aid.

Cheers
Ray


----------



## Steamchick

Thanks Ray, Interesting! That is a hell-of-a-powerful spark if you are getting metal transfer! I would have thought the metal ions are disruptive to the wellfare of the engine internals... as well as creating a very short life for the spark-plug! Is there not too much spark current? - Especially for models where spark-plugs are relatively tiny? The Champion Engineer that I advised me on plug selection testing and results, explained that the purpose of the arc is to ionise and ignite the fuel but not to erode the plug contacts, which is why they recommended copper core (for cooling the electrode) and platinum tipped plugs - which were new technology in the 1980s for longer service intervals. (_Aside_: Not really "new" technology, but a move away from the GM and Ford policy of "cheapest" - that gets the customer to return to the dealership most often for cheap servicing - so Dealers have more contact for selling new cars..., and the cheap servicing doesn't dissuade the customers from using the dealer for servicing. The Japanese manufacturer's marketing in the late 1980s was for MINIMAL servicing... (only annual) so customers come back to the dealers when they are more likely to see a new model that makes their car look dated... therefore buying the next year's  model!).
Interested to hear more...
K2


----------



## 74Sprint

Steamchick said:


> Thanks Ray, Interesting! That is a hell-of-a-powerful spark if you are getting metal transfer! I would have thought the metal ions are disruptive to the wellfare of the engine internals... as well as creating a very short life for the spark-plug! Is there not too much spark current? - Especially for models where spark-plugs are relatively tiny? The Champion Engineer that I advised me on plug selection testing and results, explained that the purpose of the arc is to ionise and ignite the fuel but not to erode the plug contacts, which is why they recommended copper core (for cooling the electrode) and platinum tipped plugs - which were new technology in the 1980s for longer service intervals. (_Aside_: Not really "new" technology, but a move away from the GM and Ford policy of "cheapest" - that gets the customer to return to the dealership most often for cheap servicing - so Dealers have more contact for selling new cars..., and the cheap servicing doesn't dissuade the customers from using the dealer for servicing. The Japanese manufacturer's marketing in the late 1980s was for MINIMAL servicing... (only annual) so customers come back to the dealers when they are more likely to see a new model that makes their car look dated... therefore buying the next year's  model!).
> Interested to hear more...
> K2


You have to remember that, that ignition was for automotive racing and at full power it draws 48 amps charging the coil! It will ignite a lean mix or rich mix just as easy as a stoichiometric mixture. Yes it is hard on sparkplugs but, when I tested it on my truck I turned the power down to about 66% and it was ok. To give you some idea of the power, if by chance a cylinder has a air/fuel mix in it, is at or near TDC, and it just happens to line up with the rotor, and you turn the ignition on (which causes a spark) half the time it will start the engine!!! So it's not for model engines. LOL I do have a CDI that will work down to 0.400ma that works nicely with model engines and will be presented here later as a kit.

Most dealers here, no matter what you take your car in for always want to charge you $1,000-$1,200. I went in for a recall and oil change and they came back saying I needed $1,200 work, I did the work myself which cost $60.00 for parts.

Cheers
Ray


----------



## 74Sprint

So I'm finally getting to solder up my scope kit. It's a JYE Tech DSO 138 Oscilloscope DIY Kit, it's their older model that's still available on the internet at Amazon for $40.00 CDN. I've had it for a while and it's obsolete, their new version is the DSO 138mini Oscilloscope DIY Kit and it is cheaper. It can go up 200Khz and 50vpp so for what it will be used for here, it is more than enough, well we'll see eh. Here is the link to it's web page DSO 138 Scope. All the surface mount components are pre soldered so it's just the through hole stuff to solder.








I also bought a clear plastic box/case for it, safer right. It's a single channel with some neat features. I wouldn't mind trying their DSO 68 kit because you can connect to your PC and use their software to display the waveforms. I was surprised to see that they we're using a STM32F103Cx processor it's actually a mid line 32 bit ARM processor so it's got some nice specs. Anyway I'll talk more about this and let you know how the soldering went. Oh it needs a 9 volt power supply.

Ray


----------



## Vietti

Ray,

I once heard that a top fuel dragster burned off the spark plug electrodes almost immediately on the start and dieseled  the rest of the way down the track-true?  Also a possible factoid that the dragster engine only turned about 800 revolutions for a 1/4 mile run, the arithmetic seems to sort of support this?

John


----------



## 74Sprint

Vietti said:


> Ray,
> 
> I once heard that a top fuel dragster burned off the spark plug electrodes almost immediately on the start and dieseled  the rest of the way down the track-true?  Also a possible factoid that the dragster engine only turned about 800 revolutions for a 1/4 mile run, the arithmetic seems to sort of support this?
> 
> John


Yes it true the plugs can burn away real quick, the plugs won't fire but they're so hot that the nitro will still ignite, they end up working like a glow plug. Nitromethane is a really weird solvent, yup that's what it really is, pour it on the ground like concrete and hit it with a hammer and it will ignite. But when it is under compression like in an engine it is very hard to light, it needs heat, which is why they usually start the engine on gasoline or alcohol depending if N/A or supercharged. Doug Doucette a local TA/D racer here was working with me on my ignition and he ran a 500CID N/A nitro burning engine, he showed me a bunch of burned plugs and the race data. You can see from the data when a plug burned away and either finished the run or went cold from the fuel. Years ago when they ran straight magnetos and fixed timing one of the problems was they couldn't really control the combustion temperature so they ran hot and when they finished the run they would throw a switch which shorted the mags out but, if there was any fuel left in the system the engine could/would keep running until it ran out of fuel. This caused several accidents when the engine would refire and the car would run into someone/something. Today they use an MSD ignition system usually the 'Grid System' and can control the timing for the whole run and usually they do the same as me and we pull timing out in third gear or the top of the run for them. The engine and sparkplug temps get to high and pulling timing out cools those temps just enough to keep detonation down and for them burning plugs but it still happens a lot.

How many RPM does a top fuel rail make in a 3.7 sec. 1,000 foot run? Well lets do the math. First the RPM of these engines is basically controlled by the load from the clutch. Most of the time these engines go from a idle of @2,000 rpm to 6,000 RPM in half a second, after 1 second it is at 7,000 RPM and never goes below that. So lets say it averages 7,000 RPM for 3.7 seconds. So 7,000/60 = 116.667 RPM per second times this by 3.7 and you get 431.667 revolutions per pass. Of course if you add in the warm up and burn out they do about 1,200 to 1,500 revolutions. If you take this out to 1320 feet (1/4 mile) the revolutions would be only about 550. This can go higher if there is a lot of slippage and the engine hits 10,000 RPM but that is dangerous. The mechanical fuel pumps can overload the cylinders with fuel and cause a hydraulic lock/boom or the engine oil overheats and breaks down causing the crank to seize boom again. I have seen this type of explosion once and all that is left is the frontend/plate and the backend/plate of the engine. Everything else is gone, there is just the ends of the block and crank ends, no rods, pistons, heads, or blower. I remember that calculation of 800 revolutions from years ago when the T/F rails were doing about 4.8 second runs and about 6,000 Hp.

Cheers
Ray


----------



## Brian Hutchings

Does anyone know about igniters, as used by Henry  Ford on his Quadricycle? I'm close to finishing a 1/4 scale model and have had some advice on the ignition but I'd like, if possible, to keep it as authentic as possible. I'm not looking for performance or even long running times, if it runs for 30 seconds or so at a time then I'll be well pleassed.
Brian


----------



## dsage

74Sprint said:


> So I'm finally getting to solder up my scope kit. It's a JYE Tech DSO 138 Oscilloscope DIY Kit, it's their older model that's still available on the internet at Amazon for $40.00 CDN. I've had it for a while and it's obsolete, their new version is the DSO 138mini Oscilloscope DIY Kit and it is cheaper. It can go up 200Khz and 50vpp so for what it will be used for here, it is more than enough, well we'll see eh. Here is the link to it's web page DSO 138 Scope. All the surface mount components are pre soldered so it's just the through hole stuff to solder.
> View attachment 128863
> View attachment 128864
> 
> I also bought a clear plastic box/case for it, safer right. It's a single channel with some neat features. I wouldn't mind trying their DSO 68 kit because you can connect to your PC and use their software to display the waveforms. I was surprised to see that they we're using a STM32F103Cx processor it's actually a mid line 32 bit ARM processor so it's got some nice specs. Anyway I'll talk more about this and let you know how the soldering went. Oh it needs a 9 volt power supply.
> 
> Ray



You'll have to make some attenuators for the input of that scope. Many things you'll measure in an ignition system are over 50v. No sense going by the way of your China coil with the scope.


----------



## Bentwings

Vietti said:


> Ray,
> 
> I once heard that a top fuel dragster burned off the spark plug electrodes almost immediately on the start and dieseled  the rest of the way down the track-true?  Also a possible factoid that the dragster engine only turned about 800 revolutions for a 1/4 mile run, the arithmetic seems to sort of support this?
> 
> John


Yes I drove top fuel dragster and funny cars but not the modern day ones. Even back then on a hard run the plugs would be burned off at the end of the run. Looking at them you could tell how bad the rest of the engine was. Burned pistons were common . We didn’t replace everything every run like today but often enough. Today al of them have onboard data logging so all you have donis look at the data and interpret it. Driving down the road we often played calculator numbers as these were relatively new devices. It doesn’t take long to arrange number against time to get how many revolution the engine turns knowing tire size and gear ratios. Total run life was about 3 minutes if all 8 pistons survived. Even back then cranks lasted only 20 runs or so for the very best that were about 5 grand then. Aluminum rods were good for 5 runs you could send them back for reconditioning once maybe. They have sedated cap surfaces so you can’t practically do them yourself few shops had tooling to do this. They often were out of round of wrist pin holes beat up so rods were expendable. If you were lucky a spun bearing crank could be repaired by a good crank shop. Cranks get twisted too John force’s tuner put onboard testing device Ed snd proved this years ago. Even cams twisted and caused valve issues. That’s why gear driven cams became standard. Vale springs went from 300 pounds on the seat to way over 800 pounds open. Push rods were made custom tapered with varied wall thickness an incredible expense back then the entire drive line became custom made from exotic materials. The rear axel tube now is bigger than a big guy arm made from 300m mar aging steel even it gets twisted. Gears are custom made too. There are no junkyard pars on these cars today. Funny car bodies used to be about 4 grand now they are carbon fiber and 30 grand or more add about 30 more grand to mount it few are painted but wrapped now days. Even nostalgia cars are very expensive to run. I forgot the blowers. They start about 30 grand. The rotor strips last a couple runs. They can take over 10000. One thousand hp to drive there are a few blower synos often using s supercharged alcohol motor to drive them for testing. It’s amazing the belts hold up for a single fun. They are custom made too using carbon fiber material. My street rod went 30k miles on a standard 8 mm belt the pulleys were about worn out from road dust but the belt was ok. This was an old school race belt that would last ten runs in the old days. Blocks and heads ar carved from a solid block or custom forged block of aluminum they don’t use coolant they have replaceable sleeves allowing various bore sizes to be used there is a lot of fechnogy in these cars now that wasn’t even dreamed of 30 years ago. It’s like our govt money is no object. Some time take you trusty calculator any figure out how much money weighs. A new $100 bill weighs about how 1 gram . A simple way is to pose the question on the kntrernet you can get the number of  semi trailers it would take to haul the proposed budget away. It’s pretty amazing. 
byron


----------



## Vietti

Thanks for all the info re drag engines.  I used to subscribe to Hot Rod magazine just to read about the engines and technology but it got so far from what a shade tree mechanic or someone on a small budget could do I quit the magazine.

NASCAR used to be interesting but now the engine/car specs are so tightly controlled there is virtually no difference car to car, purely a drivers race,which was the intent I guess.  I used to enjoy the few years of CANAM racing in the 60's where you could run what you brung, resulted in some interesting cars like the vacuum cleaner of Jim Hall(?).

I apologize and think we have hijacked this thread too far, maybe start a new one but don't know under what heading!

John


----------



## 74Sprint

dsage said:


> You'll have to make some attenuators for the input of that scope. Many things you'll measure in an ignition system are over 50v. No sense going by the way of your China coil with the scope.


I have an old Phillips scope a PM3302 I bought it years ago. It's old and almost worn out but it's still kicking and the storage part of it usually works LOL. I have 2 1x-10x but yah I should get some attenuators. I hacked a old probe and put a precision 1 meg resistor inline, it works but don't ask about calibration or tuning it LOL. Thanks dsage for reminding me.

Ray


----------



## 74Sprint

Bentwings said:


> Yes I drove top fuel dragster and funny cars but not the modern day ones. Even back then on a hard run the plugs would be burned off at the end of the run. Looking at them you could tell how bad the rest of the engine was. Burned pistons were common . We didn’t replace everything every run like today but often enough. Today al of them have onboard data logging so all you have donis look at the data and interpret it. Driving down the road we often played calculator numbers as these were relatively new devices. It doesn’t take long to arrange number against time to get how many revolution the engine turns knowing tire size and gear ratios. Total run life was about 3 minutes if all 8 pistons survived. Even back then cranks lasted only 20 runs or so for the very best that were about 5 grand then. Aluminum rods were good for 5 runs you could send them back for reconditioning once maybe. They have sedated cap surfaces so you can’t practically do them yourself few shops had tooling to do this. They often were out of round of wrist pin holes beat up so rods were expendable. If you were lucky a spun bearing crank could be repaired by a good crank shop. Cranks get twisted too John force’s tuner put onboard testing device Ed snd proved this years ago. Even cams twisted and caused valve issues. That’s why gear driven cams became standard. Vale springs went from 300 pounds on the seat to way over 800 pounds open. Push rods were made custom tapered with varied wall thickness an incredible expense back then the entire drive line became custom made from exotic materials. The rear axel tube now is bigger than a big guy arm made from 300m mar aging steel even it gets twisted. Gears are custom made too. There are no junkyard pars on these cars today. Funny car bodies used to be about 4 grand now they are carbon fiber and 30 grand or more add about 30 more grand to mount it few are painted but wrapped now days. Even nostalgia cars are very expensive to run. I forgot the blowers. They start about 30 grand. The rotor strips last a couple runs. They can take over 10000. One thousand hp to drive there are a few blower synos often using s supercharged alcohol motor to drive them for testing. It’s amazing the belts hold up for a single fun. They are custom made too using carbon fiber material. My street rod went 30k miles on a standard 8 mm belt the pulleys were about worn out from road dust but the belt was ok. This was an old school race belt that would last ten runs in the old days. Blocks and heads ar carved from a solid block or custom forged block of aluminum they don’t use coolant they have replaceable sleeves allowing various bore sizes to be used there is a lot of fechnogy in these cars now that wasn’t even dreamed of 30 years ago. It’s like our govt money is no object. Some time take you trusty calculator any figure out how much money weighs. A new $100 bill weighs about how 1 gram . A simple way is to pose the question on the kntrernet you can get the number of  semi trailers it would take to haul the proposed budget away. It’s pretty amazing.
> byron


Doug Doucette and I both agreed quick is never quick enough, you get use to the G's and speed and then you want more. So 'how fast can one afford to go' Yup I remember helping Doug change sleeves, pistons, and rods and asking him how long they last and how much doing 1 hole cost. His answer was depends on how greedy he gets for ET or about 5 runs and at the time (about 25 years ago) about $2,500 a hole which, was more than I spent on my whole car at that time. LOL
Yep glory days.

Ray


----------



## Bentwings

Vietti said:


> Thanks for all the info re drag engines.  I used to subscribe to Hot Rod magazine just to read about the engines and technology but it got so far from what a shade tree mechanic or someone on a small budget could do I quit the magazine.
> 
> NASCAR used to be interesting but now the engine/car specs are so tightly controlled there is virtually no difference car to car, purely a drivers race,which was the intent I guess.  I used to enjoy the few years of CANAM racing in the 60's where you could run what you brung, resulted in some interesting cars like the vacuum cleaner of Jim Hall(?).
> 
> I apologize and think we have hijacked this thread too far, maybe start a new one but don't know under what heading!
> 
> John


We went to the point of economics limit. Much of drag racing was match races depending on number of cars an program to be run. The name of the game was to make all of your laps or runs to get paid. Often the two quickest came back for a final round for some extra money. It forced you to run hard snd not breaknparts. Often the rule of the line was you had to take a green light to get round money. If you knew your car was in trouble you might get away just taking the green and hoping you didn’t do any further damage. I did this several times. One afte the clutch exploded. Parts were flying all over but as I backed up I saw the competitor push truck sitting on top of crushed starting lights I took the green hoping the rest of the drive line didn’t end up in my lap. Luckily it didn’t. I was crazy back then invincible as they say. We borrowed a complete clutch and with the next round guy crew changed it all out. I took a guess on adjustment and wound up winning the race. It basically paid for the damage. In 5 years we lost only 2 rounds but saved several with only minor damage. The extra round usually paid for the damage. Poor use of economics trading a dirt dollar bill for a clean one. Not quite but you get the idea. Lots of pistons were burned early ones were of weldable material so I welded them up and remachined the ring grooves. Pistons were about $200 each so an extra run or two allowed purchasing new ones . I did them for other guys too so I made a few dollars on the side.  We didn’t have aluminum blocks and heads back then do we were slways on the lookout for a used motor. Or pair of heads. Few other parts were used. I salvaged a couple blowers that I sold as rebuilt or cores.  Yeah scrounging was part of racing back then. I worked in a hot rod machine shop so I had some advantage of not having to have others do work for me.  .
I’m sure there are other things to talk about form those days. There are not many of us left.  Being able to recount this for others may help in some way. I hope so. If we get too far out of line I’m ok if someone wants to redirect. Just make a note.
Byron


----------



## 74Sprint

Brian Hutchings said:


> Does anyone know about igniters, as used by Henry  Ford on his Quadricycle? I'm close to finishing a 1/4 scale model and have had some advice on the ignition but I'd like, if possible, to keep it as authentic as possible. I'm not looking for performance or even long running times, if it runs for 30 seconds or so at a time then I'll be well pleassed.
> Brian


Well I found what your looking for but you won't like it. The info below was taken from the National Center for Preservation Technology & Training and it is from a POD cast that you can read or listen to: quadricycle-questions-with-mose-and-andrew.

Here is a section of what you want: "Mose Nowland: Well, it would take a specialist to pick out the differences. There is a slight mystery about the ignition system that is a mechanical grounding system inside of the combustion chamber. We’ve never been able to look inside of his original for his design, shape, and material he used for those moving pieces. But, George had imagined what they would be. I’m sure that he’s replicated pretty darn close because there were certain geometries that had to be accomplished that could only probably end up looking alike whether it was replicated or the original."

I know that's probably not not what you wanted to read but, the ncptt will not let just anyone touch the original never mind opening it up. But most likely it used a low tension ignition system with one or two wires going into the head and you can read more about old ignition systems here: https://www.old-engine.com/magign.htm. I would like to say that when it comes to electrical or electronics not everything can be scaled down but, you can be creative.

Ray


----------



## stackerjack

74Sprint said:


> So I'm finally getting to solder up my scope kit. It's a JYE Tech DSO 138 Oscilloscope DIY Kit, it's their older model that's still available on the internet at Amazon for $40.00 CDN. I've had it for a while and it's obsolete, their new version is the DSO 138mini Oscilloscope DIY Kit and it is cheaper. It can go up 200Khz and 50vpp so for what it will be used for here, it is more than enough, well we'll see eh. Here is the link to it's web page DSO 138 Scope. All the surface mount components are pre soldered so it's just the through hole stuff to solder.
> View attachment 128863
> View attachment 128864
> 
> I also bought a clear plastic box/case for it, safer right. It's a single channel with some neat features. I wouldn't mind trying their DSO 68 kit because you can connect to your PC and use their software to display the waveforms. I was surprised to see that they we're using a STM32F103Cx processor it's actually a mid line 32 bit ARM processor so it's got some nice specs. Anyway I'll talk more about this and let you know how the soldering went. Oh it needs a 9 volt power supply.
> 
> Ray


Well Done Ray. Looks like you're onto a winer there. Great Stuff.


----------



## a41capt

Brian Hutchings said:


> Does anyone know about igniters, as used by Henry  Ford on his Quadricycle? I'm close to finishing a 1/4 scale model and have had some advice on the ignition but I'd like, if possible, to keep it as authentic as possible. I'm not looking for performance or even long running times, if it runs for 30 seconds or so at a time then I'll be well pleassed.
> Brian


I believe my set of plans for Leon Ridenour’s version of the kitchen sink engine outline a reasonable facsimile of an igniter.  As this engine was the forerunner to his development of a workable internal combustion engine, and having some similarities to the Quadricycle engine, perhaps this type of igniter would suit your purposes.

If I remember correctly (it’s been a couple years since I built mine), he pretty much says that the builder should be prepared for some frustration in making it work. With that bit of info, I elected to go with a spark plug instead!

Good luck with your endeavor, and I hope you’ll post your completed engine running.

John W


----------



## 74Sprint

The mini scope is done and I have started using it and here is my review.
So why does anyone need a scope for? Well a scope can do everything a multimeter can except measure current directly but, even that can be measured as a voltage drop across a load. Once a person gets use to and familiar with a scope IMHO you won't want to go back to a multimeter, at least not on a work bench. This is why I wanted a portable, low cost scope for doing basic work. There is a ton of mini-scopes out there and choosing one can be difficult so do your research. 






Mine is from http://www.jyetech.com/ which I bought before xmas and is now obsolete but, is still available. I noticed that mine needs the firmware to be updated and from what I can tell I'll need my STMicro bootloader device to do that. I didn't think that a $40 mini-scope would be worthwhile but, I decided to give it a try. It is a DIY kit with all the surface mount components already soldered for you, nice. I have a very nice pencil point soldering iron with adjustable heat so soldering small components is fairly easy. But there was 2 components that were a bit difficult, the USB port and the switches because their pins were very close together.








The above pictures are from screen shots of the 7" display on my microscope.
The map of the component locations is not very clear, small, and fuzzy, so you spend a lot of time looking for part locations. The parts list for the SMD components is also on that map. For the parts you need to solder the list is part of the assembly instructions and is not a separate list. Speaking of which step 1-1 the resistors, it calls for 120 ohm resistors for R8, R12, and R13 but they gave me 120K ohm. I decided what the hell I'll try them but, nope the gain on the op-amps was way off. So I ended up putting 2 220 ohm resistors in parallel to make 110 ohms for the gain which worked out. When soldering boards I always start with the parts that are the lowest height or are covered up somehow and go up from there. The instructions follow the same way. I did kind of cheat when I soldered the 2 x 20 pin header. I soldered one row with wire solder and switched to paste on the other row. With the paste I just had to run the soldering iron down the row for a clean job. I try to use solder paste out of a syringe whenever I can because when the paste melts it goes straight to the pins and there is no bridging. Excellent stuff, try it if you can, a little goes a long way and it would have made soldering the USB and switches a breeze.

The soldered board.







Those unfilled holes are test points and are used when you put the board into self test mode for troubleshooting. 
Finished board.




It's at this point you have to start the testing and doing the setup routine. _MAKE sure you follow all of it as written._






No power supply is supplied so you need a 9v - 12v DC supply, either a wall-wart or a 9v battery but they don't supply the connecting cable for the 9v battery either. I used 12v and it does run a bit warm, but it ran for 20 hrs. straight so it's fine with 12v. One other problem I ran into was I had no signal at the 'Test signal ring' so I ended up using my function generator and a 35Hz square-wave signal for adjusting C4 & C6.





It took a bit of playing with the controls to get a nice signal displayed. It is a simple DSO or digital storage scope and I didn't expect for the price to be comparable to a $500 -$2,000 scope but, I was surprised to see it had some neat features. One is the single trigger capture, another is the on screen readouts that can be turned on and off.








So does it work? yes it does for low frequency stuff. One thing that bothered me was in the instructions it says that there is no guarantee that it will work! They should have said that before I bought it. It does take a bit of learning to make it useful though.
What you are seeing above is the output of the A1102EUA-T (BOPS of 245 Gauss) Hall-effect. I changed the Hall-effect because the one I was using (AH3366Q-P-B BOPS of 100 Gauss) was way too sensitive. To get the pulse above I had to move the magnet as fast toward and back as I could. As you can see the pulse is negative going which is the norm for most Hall-effects, almost grounding out the output. It's not showing the Freq, Cycl, PW, or the duty because I have it set for single trigger mode. What I wish I could show you is how the trailing edge moves back and forth which would change the timing but, that's coming. In my next instalment I show you the outputs of the CD4047 and the MOSFET, Transistor, and a IGBT. So is this mini-scope worth $40 ? I think so right now, I just wish the triggering was better, the case had a place to put the 9v battery, and external triggering. I hope to replace my old Phillips scope with a new DSO scope for around $600 sometime soon.

Cheers
Ray


----------



## bluejets

Ray, I've had a similar unit since the flood here in 2013 took all my workshop.
Works great.
Previously had a bench unit but this is much more portable and does the job.
Changed it to include a rechargable lithium pack and on-board charger module via mini usb all housed in a project box "glued" to the back.


----------



## 74Sprint

I saw that one on Amazon after I bought mine and thought I should have gotten that one. Oh well but, it's not a majour tool for me just something handy for doing quick checks. I see that one had a better review than mine and it sells anywhere from $44 - $56 CAD depending on the options, funny how they have the same screens and buttons. They are better than lugging around a old 10kg scope.  

Cheers
Ray


----------



## 74Sprint

Timing pulses:
Until I get a timing wheel put together with magnets it will be hard to show the auto advance of the trigger pulses.
I setup the CD4047B to show the difference between the fixed timing pulse (leading edge) and the auto advance (trailing edge) using just my hand.
Before I go further I want to explain that the actual timing and it's accuracy depends on 3 things; 1 the strength of the magnet, 2 the sensitivity of the Hall-effect, and 3 the distance of the Hall-effect to the magnet. If all these 3 stay the same then setting the timing it should remain constant. I have found and I'm sure people using Hall-effects on here also have found that with the crank moving back and forth can cause the timing to skip around a bit. I find that on a brand new engine with brand new crank ignition the timing is pretty much stable but as the parts wear the timing starts to skip around a bit. Now passing a magnet back and forth past the Hall-effect with my hand there is no way I can duplicate a running engine, my hand is simply not fast enough or consistent enough. But I have a couple of pictures to show you.









I know it's hard to see but if you look at the trailing edge you can see that the edge has moved a little to the left which, would mean that the timing has advanced. How much well it's about 4usec. Which if you do the math......
Lets take an engine (2 or 4 stroke it doesn't matter) running at say 5,000 RPM so
5,000 / 60 = 83.33 RPM per sec.
1/83.33 = 0.012sec. per RPM
0.012/360 = 0.0000334sec per degree or 33.4usec per degree.
So changing pulse width by 4usec with my hand which, is about 200 RPM it will advance the timing by about 1/8 of a degree. This change will become more evident (larger change) when I use a timing wheel with more speed and my big scope, with 2 channels and better triggering.

I did find out with the scope that my dwell was 40msec which is more than the small coils could handle. I adjusted that down to 2msec and will start testing different coil driver components. Also I found that the the leading edge timing (fixed) stayed pretty much rock solid as best as I could with my hand. So things look promising.

cheers
Ray


----------



## 74Sprint

I finally found some time to get to the auto-wreckers and got 4 different types of ignition coils, all 12 volt. I tested the coils for strength along with some different types of IGBTs, MOSFETs, and some transistors. I didn't actually measure the voltage or current outputs from the coils so I don't know the joule outputs. I hate when they measure coil outputs in joules or watts because those measurements mean nothing and is just a marketing ploy. There is no difference if I have 1,000 [email protected] amp per second or 1 [email protected],000 amps per second the wattage/joules is the same. But the 1,000 volts will jump a gap easier than 1 volt. 

Except for the Ford coil where I used just the NGK plug, I used a 349 ohm ignition cable with the Dodge and old style GM coils, the LS1 cable had 354 ohms, and the plug I used for all testing was a NGK UR6GP sparkplug with 4.4K ohms.

The charging devices I ended up using for the most testing:
STGF3NC120HD    7 A, 1200 V very fast IGBT with ultrafast diode    QTY 1    UNIT PRICE $2.45000    v-good spark
IPP25N06S3L-22IN-ND    IPP25N06S3L-22    MOSFET N-CH 55V 25A TO220-3    good but obsolete

I usually don't like using transistors because the cheaper ones are usually slow, can't handle the power both switching or higher duty cycles. They are also harder to get the biasing right. Yes they do make transistors that can handle problems but they also cost a lot more. So that leaves us IGBTs and MOSFETs to play with. IGBTs are basically BJTs (Bipolar Junction Transistor) mated to a MOSFET. The MOSFET handles the base biasing and current of the BJT. This makes it easier to turn the transistor on but, makes it harder to turn off. Sometimes but not all the time you need to bring the gate voltage negative or below zero to turn it off. Most of my IGBTs were like that and only the STGF3NC120HD I had worked with zero turn off volts and had fast switching that could handle the inductive loads. The EMI from the coils didn't seem to bother it also, I guess because of the wire resistance. The IPP25N06S3L-22 MOSFET I have also worked well but, not quite as good as the IGBT. The spark colour was good but not as fat. As I said all the coils below were 12 volt, so they didn't work at 5 volts.

12v Coils tested:

DODGE 1998-2003 RAM 1500 PICKUP    Primary 1.1k ohms   Secondary 12.92k ohms   V-Good spark
SKP SKIC522 {#56027966, 56028172, 56028172AB}    STANDARD MOTOR PRODUCTS UF198T    CAD$8.68

LS1 used from 1999-2007, coil blacks (-) red (+) blue (sig)    CAD$17.94 to CAD$121.24 excellent spark without using a transistor but 12 volts is required
Found mostly on SILVERADO 1500 4.8-6.0L

GM 4 WIRE old style COIL  GM 1985-1994    Primary 0.45 ohms   Secondary 8k ohms   STANDARD MOTOR PRODUCTS DR37T    CAD$14.03    Good spark
FORD 2.3L FORD FOCUS 2003-2011 coil on plug     Primary 0.6 ohms   Secondary 5.4k ohms   CAD$9.57    good spark
3 different CDI coils had spark but very weak. These coils usually need between 100-120 primary volts to work.
The Dodge coil to me was the best overall for price and performance. The problem with it though is getting a new connector which was $23 CAD so best to get a coil and pig-tail from the wreckers or just a pig-tail. You can also use 2 small width female blade (red) connectors and glue them in. I don't see why people talk about the Ford COP being so good. It uses a long spring to contact the sparkplug, I guess one could solder a lead onto it after cutting it down. The Ford COP also has an inductor built into the spring for noise suppression. The old style GM 4 wire split connector that secures from the top was ok. This coil along with the Ford COP would make good coils for a CDI ignition. The GM LS1 smart coil was the easiest to hook up and make work and it had the best spark overall. This is probably because it has the transistor built right into it but, using just the Hall-effect wasn't strong enough to trigger it. More testing needed. This LS coil was also the most expensive and it has a pencil point projection for the coil wire to attach but, if you squeeze down on a normal coil wire female terminal you can make it work. So if your going to get one from the auto wrecker make sure to grab the coil connector and a plug wire. It is very easy to get this coil working just a few simple components is all that is needed. And it will work with either points or Hall-effect.

I was disappointed by the Ford coil's spark until I measured the secondary coil and found it was on the small side. I'm not sure but, I think if I were going to use 12 volts and wanted a simple ignition I would probably go with the LS1 smart coil from the auto wreckers. The current draw when not firing is just 23ma avg. 19-25ma range so this is excellent. If I were building a multi cylinder distributorless engine I would go with it. But the LS1 smart coil does present me with a bit of a problem and that is deciding if I should go with an TCI or CDI distributorless ignition for my race car. The LS1 Smart Coil Will Not Work With a CDI Setup. 

Did you notice that no where have I ever mentioned a ballast resistor? Well that's because my circuit doesn't need one, it has adjustable dwell. For this testing I turned the dwell up to 3msec. to be fair on the testing. On every car that I have worked on that used a ballast resistor except the Fords with the built-in coil resistor, a stupid idea, bypassed the ballast resistor/wire during starting. This gave full voltage and current during starting to the coil and this would fall back when you let the key go.

Hall-effect triggering is based on it's Gauss value. What this means is that if you use a H-e with a gauss of 50 it will turn on sooner than with one that has a gauss of 350. In real life this means that if you use a strong magnet the H-e could turn on when the magnet is 2" away instead of a 1/4" away. On a small diameter wheel this would matter a lot and most likely drive you nuts trying to time the engine. I ordered and tried about 8 different Hall-effects and the one I like the most is the A1102EUA-T by Allegro, it's easy to find, popular, and is fairly cheap. I would like to find one that does have a higher gauss trigger point that is just as easy to get as the A1102.

Next up is to make a spinning timing wheel and some movies.

Cheers
Ray


----------



## stevehuckss396

Yes! We want movies!


----------



## 74Sprint

stevehuckss396 said:


> Yes! We want movies!


Yah I guess movies are proof of concept. LOL


----------



## stevehuckss396

I like watching movies of that stuff.


----------



## dsage

Steve:
Show us a movie of your GIANT spark plug.
LOL


----------



## stevehuckss396

Here you go. It's a 4x scale model of a champion 3x. They would be found in the ford model a among many other engines from the 20's and 30's.


----------



## 74Sprint

The simplest ignition I can come up with besides points.
Just a quick update on the LS1 smart coil and driver board. I tested the coil a bit more and the required driver components. It will work with just a Hall-effect but it's not consistent. To correct this a PNP transistor is needed to drive the spark signal. The signal drives a transistor inside the coil so more current is needed. I went to a 1K ohm pullup resistor and I don't want to go below that because the Hall-effect or most of them can only handle 20ma of current. I could go down to 600ohms for 20ma. I did notice that just like older GM designs it needs to see a positive going pulse to trigger. The board is 17mm wide and 26mm long. C1 should be 0.01uf to 0.1uf ceramic depending on Hall-effect used. In the setup below the coil will fire after the magnet passes the Hall-effect or when the LED turns off. No dwell control or limiting resistors are needed because the coil handles all that. Just add a Hall-effect, 12 volt supply, and a LS1 smart coil. You don't have to use the 2N4403 (PNP), you can use something similar. I used it because I had them.

























I included a pdf below that can be used to turn a CD disk into a timing wheel. I have others to share with timing events. If there is enough interest I'll get extra boards made. Oh I also cleaned up the board design a bit, things like better pours and changed Q1 to a wide T092 pad.

Cheers
Ray


----------



## 74Sprint

stevehuckss396 said:


> Here you go. It's a 4x scale model of a champion 3x. They would be found in the ford model a among many other engines from the 20's and 30's.



That is totally awesome and funny as ever, I like it.LMAO.


----------



## bluejets

Ray,
       If you check Allegro site on their hall effects, they always recommend a 0.1uF on the supply line AND close as possible to the device.
I usually mount it right on the base of the hall effect legs.


----------



## dsage

stevehuckss396 said:


> Here you go. It's a 4x scale model of a champion 3x. They would be found in the ford model a among many other engines from the 20's and 30's.



Ah Yes. I remember it well from NAMES.
Thanks.
I'll be looking for that kind of performance from 74Sprints circuit.
BTW. What's the gap.
Thanks


----------



## stevehuckss396

I think the gap was 5/8 or 3/4. Dont remember exactly. Now I run a 1/4 inch gap.


Hello Sprint

Simple is great. My biggest concern is sparks per minute. I build multi-cylinder engines many with 8 or more cylinders. Also dont need super high energy as my plugs are gapped at .012 to .015 so can get the spark thru the tiny distributor and to the plug.


----------



## dsage

74Sprint said:


> The simplest ignition I can come up with besides points.
> because I had them.



Ray. I'm not sure how "Smart" your smart coil is and also you say you have controlled dwell BUT. What happens when the engine stops with the points closed or the hall activated?
It seems this circuit still puts the coil in jeopardy (energized continuously) if the engine stops in the right position. Maybe I missed something.


----------



## dsage

stevehuckss396 said:


> Simple is great. My biggest concern is sparks per minute. I build multi-cylinder engines many with 8 or more cylinders. Also dont need super high energy as my plugs are gapped at .012 to .015 so can get the spark thru the tiny distributor and to the plug.


Steve:
Do you still have my coil driver I gave you?
It'll be your best bet so far.


----------



## 74Sprint

bluejets said:


> Ray,
> If you check Allegro site on their hall effects, they always recommend a 0.1uF on the supply line AND close as possible to the device.
> I usually mount it right on the base of the hall effect legs.


I saw that and I've also seen where they want 2 caps, it's just the standard decoupling thing. 



dsage said:


> I'll be looking for that kind of performance from 74Sprints circuit.


I won't be doing anything like that here. I haven't made a Tesla coil in years since I was a teenager.



stevehuckss396 said:


> Hello Sprint
> 
> Simple is great. My biggest concern is sparks per minute. I build multi-cylinder engines many with 8 or more cylinders. Also dont need super high energy as my plugs are gapped at .012 to .015 so can get the spark thru the tiny distributor and to the plug.


I understand that "sparks per minute", for me it's sparks per second of at least 333.33 or 10,000 V8 RPM on 1 coil. The amount of spark required varies by the fuel and compression. Here on this forum those requirements are low. In my world those requirements go from 8Kv to 65Kv and spark energies from 60mjoules to 800mjoules. Fuels from regular pump gas, alcohol, alcohol/nitro(50/50), to 118 octane race gas and compression ratios of 4.5:1 to 17:1 naturally asperated to 16:1 supercharged gas engines running 80 lbs. of boost. There is also my little .40 Webra engines I want to convert.

What I'm presenting here is just alternatives so use them or don't, that's up to the individual and it doesn't really matter to me either way. No one on this forum needs a 56 amp racing ignition with a 15 minute run time before overheating. I've never seen anyone on here use a 44 amp MSD magneto and I never will. There's what 4 or 5 people on here selling ignitions of their flavour and then users want as small as possible to the least amount of power to as low of cost as possible. I've read pretty much all the threads pertaining to ignitions on here so I am informed.  Back on the RC Group build us 'the designers' got tired of people wanting all kinds of things but not help out which led to the project dyeing. There's no way I'm going to get rich selling little ignitions here, I'll find that in automotive racing and industrial electronic segments. From what I've seen on this forum the electronics here is pretty simple, like stuff from the 60's, no where near like what's on the RC forums. Besides Steve why should I buy your sparkplugs when there are others making them? Well I'll buy from you when I need them because you are on this forum and you're a small time seller and I try to support small time sellers. I'm on this forum because I like reading about the builds and one day when I have room I'll start making model engines but, for now I have to stick to small pre-machined 2 & 4 strokes and automotive engines. I'm on a journey.

Cheers
Ray


----------



## stevehuckss396

Well keep on trucking Ray. I like following your work even though i only understand about 20% of it.


----------



## dsage

Ray:
That is not the output from a Tesla coil. It's a seriously wicked spark (as Steve indicated) perhaps 5/8" long. Have another look at the video.
My challenge stands. SHOW us a similar output from one of your circuits.
The only reason the module Steve has employed  in his big spark plug cannot be used in a car ignition system is that it is an epoxy encapsulated device that self generates sparks at a fixed rate. Also it will only run for several seconds before it self destructs. If it could be controlled it would produce way more ignition spark than anyone needs.


----------



## 74Sprint

dsage said:


> Ray. I'm not sure how "Smart" your smart coil is and also you say you have controlled dwell BUT. What happens when the engine stops with the points closed or the hall activated?
> It seems this circuit still puts the coil in jeopardy (energized continuously) if the engine stops in the right position. Maybe I missed something.


For starters I didn't term the phrase "smart coil" the automotive community did. On this coil just like the original GM HEI 4 pin module it starts charging on a positive going pulse and then discharges as soon as the pulse goes towards negative.
Nothing happens because it needs to see a positive going pulse not a level one. They call it a smart coil because the driver circuit is built into it. You only need battery positive, negative and a 5v-12v positive fire/signal pulse.


stevehuckss396 said:


> Well keep on trucking Ray. I like following your work even though i only understand about 20% of it.


----------



## 74Sprint

stevehuckss396 said:


> Well keep on trucking Ray. I like following your work even though i only understand about 20% of it.


I will.


----------



## 74Sprint

dsage said:


> Ray:
> That is not the output from a Tesla coil. It's a seriously wicked spark (as Steve indicated) perhaps 5/8" long. Have another look at the video.
> My challenge stands. SHOW us a similar output from one of your circuits.
> The only reason the module Steve has employed  in his big spark plug cannot be used in a car ignition system is that it is an epoxy encapsulated device that self generates sparks at a fixed rate. Also it will only run for several seconds before it self destructs. If it could be controlled it would produce way more ignition spark than anyone needs.


No I won't be showing you that, at least not right now maybe in a year or so. Why well I don't have the time or money to complete that project just for your fun. You definitely need to explore and research more about what's going on besides this forum. Did I hit a nerve with you? Seems like it. Are you afraid your sales will drop? I haven't criticize your ignition now did I. Your ignition works be happy. As you said though a spark like that is not useful for IC engines and I agree.

Cheers
Ray


----------



## 74Sprint

Steve video in the works right now. I just have to figure out how to shrink it's size.

ray


----------



## dsage

74Sprint said:


> For starters I didn't term the phrase "smart coil" the automotive community did. On this coil just like the original GM HEI 4 pin module it starts charging on a positive going pulse and then discharges as soon as the pulse goes towards negative.
> Nothing happens because it needs to see a positive going pulse not a level one. They call it a smart coil because the driver circuit is built into it. You only need battery positive, negative and a 5v-12v positive fire/signal pulse.


Ok. Thanks for the info. I'm not familiar that one. I wasn't aware that there were coils that had an edge triggered "module" (so to speak) inside. The typical multi-wire coils I am familiar with have a simple transistor driver inside.  Which saves you from having an external driver. The input 5v signal is a simple on/off drive for the power transistor inside the coil. The transistor driver is on (and the coil driven) as long as the 5v drive it high.
Interesting. I'll have to research that some more.
Thanks


----------



## 74Sprint

Ok so here is my first video showing how easy it is to get a LS1 or 2 smart coil to fire with a Hall-effect. I forgot too mention that the coil draws a quick 6-7 amps when firing and is why I changed the 2n4403 PNP to a MOSFET and IGBT but even these will get hot and the spark will fade, best to use a heat sink. The video
LS1,2 Smart Coil Triggering was done with a MOSFET 3N06L22 obsolete now. I also tried a IGBT GB14C40L also obsolete but both worked ok. I also made a few tweaks for longevity. Oh sorry about the lighting.

The changes, once again if anyone wants the Gerber files to make your own boards just ask me.










Cheers
Ray


----------



## dsage

I don't have any "sales" of my ignition driver.
In fact I have built more than 20 of them and given them away. They are built and used by a lot of model builders on the West Coast and it was featured in Model Engine Builder Magazine as a DIY project.
It's not an ignition "system" per-se. It's just a dwell protected coil driver. And was meant to replace the TIM-6 driver that had a bad habit of burning out (very expensive) model coils and the transistor.
It's not fancy but it's all that is required if you have a good basic 2-wire coil around. Good for any sized engine really and limited only by the coil.
You can find the circuit for it on this forum.


----------



## dsage

Ray:
FWIW it seems to work. Thanks.
Where was the current measured?
I have to wonder why the transistor ever gets hot? The maximum power would be 12v x 20ma (led current plus a couple more for the 5k and 1k resistors) or 0.25 watts (give or take).
Are you sure the transistor is turned on properly? The ON resistance of the IGBT or a MOSFET should be milli-ohms and should dissipate almost no power. (the whole reason for using them)
If it's a MOSFET you're using then your bias is possibly correct but transistor dissipation at say (20ma and say .01 ohms on resistance)
I squared R = .02X .02 X .01ohms = about 4 MICRO WATTS.
The biasing is not correct for an IGBT.
All that aside a common bi-polar transistor (in a different arrangement) is all that should be required if all you are doing is signalling the coil to activate and it's doing all the heavy lifting. Apparently the activation signal only requiring 18ma or so.


----------



## 74Sprint

dsage said:


> Ok. Thanks for the info. I'm not familiar that one. I wasn't aware that there were coils that had an edge triggered "module" (so to speak) inside. The typical multi-wire coils I am familiar with have a simple transistor driver inside.  Which saves you from having an external driver. The input 5v signal is a simple on/off drive for the power transistor. The transistor driver is on as long as the 5v drive it high.
> Interesting. I'll have to research that some more.
> Thanks


The only problem with them is they are expensive. For Pro cars MSD wants $1,000 USD for a set of 8, I can get 8 used ones for $75 at the wreckers. Mind you I can get the Ford coils for $10 each new. Or from Rock-Auto new from $18 CAD plus shipping. I've seen a lot of people in the old days, not so much now use the old 4 pin GM HEI for a coil driver and that one I know has a 40msec. pulse at 650 RPM and goes down as the RPM goes up. I didn't have the CD4047 hooked up in the video. I still have to make a wheel that will fit on my electric motor but, that will be my next video using my big 2 channel scope. It's like I said before Dave how much spark does one need for the models on here. I think your design will do just fine, where as mine are a lot more complicated and more expensive. Yes I read your build, it was a good read. As for sales, on the RC Groups forum a lot of people were trying to out do each other and some got really p_ssed thinking they were going to get rich and criticized anyone that wasn't in their camp. Sorry if I implied something like that. All I'm showing here is alternatives, that I've come across. All of this is leading me to a processor controlled distributorless ignition system for my racecar. I would rather use the $3,000 to buy a lathe or mill.

18ma with no magnet and 9ma with the magnet and 6-7 amps firing.

Cheers
Ray


----------



## stevehuckss396

Thanks for the video Ray. Would this system work for a 9 cylinder up to 4000ish rpm?


----------



## dsage

Ray:
FWIW I had a look at the specific transistor you are using. I didn't realize that the MOSFET you are using is an N-channel enhanced device. 3N06L22 .
Since you are using it as a high side driver (not recommended) it will never be properly turned on. The gate will need to go at least 1.7 volts above the source (Vgs ot Vth -  See the spec sheet). Which means if the transistor is going to be fully ON the gate and source will be at almost the same voltage as the supply (12v) and the gate will need to be 12+1.7 - 13.7 volts minimum to keep it turned on. So this helps explain why the transistor is getting hot. It is not fully on (20milli-ohms resistance according to the spec sheet)
You should be able to measure this with a meter across drain and source when the transistor is on (no magnet on the hall sensor). The voltage from drain to source should be very low (like near zero).
A better solution would be to arrange for a low-side driver or use a P-channel device.
Even a regular bipolar transistor will suffer from this same problem. (i.e the base needs to be above the Emitter (and collector in this case when it's on) by .7 volts. An IGBT has another set of problems but suffers from the same issues.
Just FWIW.


----------



## 74Sprint

dsage said:


> Ray:
> FWIW it seems to work. Thanks.
> Where was the current measured?
> I have to wonder why the transistor ever gets hot? The maximum power would be 12v x 20ma (led current plus a couple more for the 5k and 1k resistors) or 0.25 watts (give or take).
> Are you sure the transistor is turned on properly? The ON resistance of the IGBT or a MOSFET should be milli-ohms and should dissipate almost no power. (the whole reason for using them)
> If it's a MOSFET you're using then your bias is possibly correct but transistor dissipation at say (20ma and say .01 ohms on resistance)
> I squared R = .02X .02 X .01ohms = about 4 MICRO WATTS.
> The biasing is not correct for an IGBT.
> All that aside a common bi-polar transistor (in a different arrangement) is all that should be required if all you are doing is signalling the coil to activate and it's doing all the heavy lifting. Apparently the activation signal only requiring 18ma or so.


Your right the biasing is not correct but, I just threw it together with what I had laying around. I really didn't think anyone would be interested in it because the coil is 12v and expensive to buy compared to other coils. If there is enough interest maybe I'll further research the use of this coil. I'd really like to do something like you did for a 4-6 volt ignition. I do have a CDI ignition for 4.5v-15v that I'll show later when I have time and that one does work. I have a video of it on my YouTube channel. But it was designed to be used with a PIC12F1840 microcontroller as the signal provider.

The current was measured coming out of the power supply so that was overall draw. Again your right there really shouldn't be that much draw on the signal for the transistor, IGBT, or MOSFET to get hot which is why I went with the 2N4403 PNP first. I found this schematic today that someone made up, I don't know if it is correct. I don't really see GM giving this info out. It's signed by Bowling & Grippo who are the designers/controllers of the MegaSquirt project.





I guess the best thing to do is bias and connect things properly and measure the current draw on the signal line. Maybe later today and get I'll back to you on that. I can also go to the MegaSquirt website and see what they are using to signal the coil.

Cheers
Ray


----------



## 74Sprint

stevehuckss396 said:


> Thanks for the video Ray. Would this system work for a 9 cylinder up to 4000ish rpm?


Yes it would. On the LS engines it is a coil near plug setup so they use 8 coils. But I guess only one could be used. I'm going to use 8 coils for my car next summer with a cam & crank signal to keep the firing order correct. Sometime this winter I'll put it on my distributor test bench and see what the RPM is that the coil max's out at and let you know.

cheers
Ray


----------



## 74Sprint

dsage said:


> Ray:
> FWIW I had a look at the specific transistor you are using. I didn't realize that the MOSFET you are using is an N-channel enhanced device. 3N06L22 .
> Since you are using it as a high side driver (not recommended) it will never be properly turned on. The gate will need to go at least 1.7 volts above the source (Vgs ot Vth -  See the spec sheet). Which means if the transistor is going to be fully ON the gate and source will be at almost the same voltage as the supply (12v) and the gate will need to be 12+1.7 - 13.7 volts minimum to keep it turned on. So this helps explain why the transistor is getting hot. It is not fully on (20milli-ohms resistance according to the spec sheet)
> You should be able to measure this with a meter across drain and source when the transistor is on (no magnet on the hall sensor). The voltage from drain to source should be very low (like near zero).
> A better solution would be to arrange for a low-side driver or use a P-channel device.
> Even a regular bipolar transistor will suffer from this same problem. (i.e the base needs to be above the Emitter (and collector in this case when it's on) by .7 volts. An IGBT has another set of problems but suffers from the same issues.
> Just FWIW.


Yup, as I mentioned above I just threw it together but, I will need to sort this out before the coming spring. I'm going to use a decade counter that will reset the count in/after the 8th count and use an 'AND gate' with the cam & crank signal as a lock-out to keep the sequence in time, I hope. LOL
I'm sorry if I don't get things moving along fast enough but, I have 2 projects that need to be updated and right now they earn me 10's of thousands in licensing fees. It took me a year to convince STMicro to release to me their RTOS which is the only one recognized by UL. Design and test = 1 year, UL testing = 1 year, Patent under small business = 1 year, cost for UL certification = $50,000, R&D = $?, patent = $2,500  it sucks it sucks it sucks.

Cheers
Ray


----------



## 74Sprint

Ok more on this 'smart coil' thingy. So I finally biased and connected things up properly instead of just throwing it together. I went back to the 2n4403 PNP transistor tried different biasing to get things closer to where they should be, note this circuit is not optimized, that will come later. But it is useable the way I have it now.

So signal current is 0 with the magnet on the Hall and 4ma without the magnet. Signal voltage going into the coil is 0 and 7.65v magnet held on and off. In both cases the coil did not fire. The coil only fires when it sees the voltage rising above 4 volts. If the voltage is steady at 7.65v or 0 it will not fire. Temperature rise on the transistor was 1.5C and 1C on the Hall, which was nice for a change. I should mention I decided to try a SS441R Hall that I bought to try out, it was too sensitive. Hall on was at 3/4" and off at 1". The coil did get warm which is normal for these coils but, it was just warm to the touch and no way near hot. These coils are used in many different makes of cars under Delphi as manufacturer, I use RockAuto to find out which makes. Just search for part number  "STANDARD MOTOR PRODUCTS UF262T" or "ULTRA-POWER UF262"  or just "CHEVROLET > 2006 > SILVERADO 1500 > 5.3L V8 > Ignition > Ignition Coil" and search the part numbers. The coils were used from 1999 to even today I believe.

Because the 'smart coil' uses such low power for a signal it would be able to use something like an Arduino board to signal several coils for multi cylinder engine using 1 board for each coil for each cylinder. This means one can make a programmable ignition curves. But one would need both a cam & crank signal. Most Arduino boards can drive a 20ma load so it should work here.

Let me know if something is out of wack and I'll fix it up, otherwise I've ran out of time for this 'smart coil' thingy. But I will come back to it in the winter.

Cheers
Ray


----------



## 74Sprint

A little more about the 'smart coil' circuitry. The coil fires when the LED goes out. This is because I'm using a PNP transistor which, kind of makes things look like they are working backwards. When the magnet is near the Hall-effect the Hall goes to ground or negative potential this turns on the 2N4403 which provides a positive going pulse which tells the coil to start charging. As soon as the signal goes level the coil fires. The dwell time is set by the coils internal circuitry and varies with RPM as the Hall's pulse width shrinks with higher RPM. GM uses Hall-effects pretty much like everybody else now a days for the crank & cam signals.

You don't need to use a 2N4403, you can use something with similar specs. I used it because I have about 500 of them. I went to the auto-wreckers today and got 8 coils, wiring harness' for them, and sparkplug wires for $110 CAD. They will sit in the garage until I get time to finish up an Arduino ignition system I'm working on for the racecar. I was going to do a CDI ignition but I think I'll do the distributorless TCI ignition first using the LS1 coils. Well that's about it for this puppy until later.

Cheers
Ray


----------



## dsage

The LED is backward. It's never going to light.
But, if you turn it around the transistor will always be on.
You need some current limiting for the base of the transistor. The Hall sensor and the transistor likely won't survive since it is trying to short out the supply through the transistor base emitter junction.
Using the points the transistor will be toast instantly.
But you should know all of this.


----------



## 74Sprint

dsage said:


> The LED is backward. It's never going to light.
> But, if you turn it around the transistor will always be on.
> You need some current limiting for the base of the transistor. The Hall sensor and the transistor likely won't survive since it is trying to short out the supply through the transistor base emitter junction.
> Using the points the transistor will be toast instantly.
> But you should know all of this.


Your right Dave I should know this better. I just recently lost my step-father and I guess my mind isn't fully focused.
Anyway, I switched the LED to the high-side so it comes on when the Hall goes to ground (magnet on) and coil fires when the LED goes out (magnet off). The LED is fine. You would be right about the transistor if it were driving the coil but it's just supplying only a signal. As for the transistor the base doesn't need any current limiting because of the 1K resistor on the collector and the 'smart coil' is only drawing 4ma. For points I forgot to say to remove the pull-up resistor R1 with points. I have the circuit running right now and it's been points closed for 30 minutes. The one problem is the points resistor is up to 28.3C so I recommend using a 1/4 watt instead o the 1/8 watt. The coil fires as soon as the points open and turning off the resistor and LED.

Thanks for keeping me on my toes Dave.

Cheers
Ray


----------



## 74Sprint

This is the new circuit running like it was using points.





Your browser is not able to display this video.



















YouTube link below.
LS1 coil and points

Cheers 
Ray


----------



## dsage

No. Actually you are wrong. Look at the transistor again. You have 12v on the emitter and with the points closed you have ground on the base (through the points). With nothing limiting the current through the B/E junction the transistor will fry. It's the same as putting a diode right across the supply. It doesn't matter what the collector is doing for a living.
I can't comment on how you are getting away with it. Perhaps your supply is current limiting.


----------



## 74Sprint

Ok Dave, I see what your talking about, I thought you meant the LED. My bad, I had the drawing wrong but, the bread board is correct which is why it didn't blow up. K new schematic. Oh power supply is 22 amps, I should limit the current. I need to slow down and check myself. 
Since I'm including the Gerber board files some people may not know about Gerber Viewer to read the board files and use to make boards.
Thanks again Dave.

Cheers
Ray


----------



## dsage

Your almost there. I think I've corrected at least three major errors in your circuits.
For anyone else that has been following along my advice would be Caveat emptor .
I'll stop commenting on your circuits now.


----------



## 74Sprint

dsage said:


> Your almost there. I think I've corrected at least three major errors in your circuits.
> For anyone else that has been following along my advice would be Caveat emptor .
> I'll stop commenting on your circuits now.


Dave I really don't mind your constructive comments at all. Besides it shows I'm human like everyone else LOL. But yes I do need to slow down and concentrate on what I'm doing. For years I always had someone double checking my work and I double checked theirs. It's only the last 5 years that I'm by myself. But I think we have beaten this 'smart coil' circuit enough and time to give it a rest.
Thanks again Dave
Cheers
Ray


----------



## JuanC

I am looking for help to install a Hall timing on my 10kw Generator so that I can change the timing at will and also get rid of the "back end spark".  Any ideas?  I am looking into the TIM 6, but this will not remove the "back end spark".  I wonder if somebody knows of a system that already does this?


----------



## dsage

What's a "back end spark"


----------



## JuanC

It's also called the "Wasted-Spark-System ".  It is the inevitable energizing of the spark plug at the end of the exhaust cycle on a 4 stroke engine using a distributor with a "points" system or a small engine with a magnet in the flywheel system.   Most engines do not have this issue anymore becuase they use a "Coil On Plug" system and an electronic triggering mechanism.

The question is:  what circuit can I use to that it sends an intermittent signal that I can use to cancel the ignition triggering in every other rotation of the camshaft.  In other words:  when the magnet passes the first time, the system will be on and remain on, and when it passes the second time, it will be off and remain off.  "ON" on odd passes and "OFF" on even passes.

This is just for a regular back up generator from Home Depot that runs with gasoline. These one piston engines have the most basic type of ignition where they put a magnet on the flywheel. The lawnmowers and gokarts also use this type of ignition system. The reasoning behind it is that you do not need an electrical system to run the engine. You start using a pull cord and then the "alternator" is embedded in the engine. The system works like this: at the desired "timing" moment, the magnet embedded in the flywheel passes under a well positioned coil that generates the electrical juice for the spark. The problem is that, being a 4-stroke engine, the crankshafts does two revolutions for to complete the 4 strokes. Hence the spark plug fires twice during the 4 strokes. First at the appropriate time before the compression stroke ends (triggering the explosion and consequent expansion on the "power" stroke), and at the ending of the exhaust stroke, when the exhaust valve is open, and causing a "back end explosion" if there is still fuel remnants on the air mixture.


My idea will be to install an electrical circuit with a regular ignition coil since this generator comes equipped with a 12V starting system, just like a car. So I was thinking to use a hall effect sensor that is triggered by a magnet in the flywheel. I can change the timing by changing the position of the magnet. But the circuit will need to have a design so that on one revolution activates the spark and on the next revolution it cancels it. I am looking at two designs that are on youtube to do the hall effect system, but I need to add the "back spark" removal system to it.  My idea is to use two hall effect sensors where the first sensor opens and closes the second sensor, which is the one that triggers the ignition system. The first sensor will have to be connected to a system where, after one pass of the magnet closes the circuit and remains closed until the magnet passes again and then opens and remains open, until it passes again, and so on...

I have attaches some pictures below of the system I have and the circuits I have found in youtube that I'm considering using.  Please search and watch these 4 youtube to get a better understanding:


IGBT Transistorised Electronic Ignition using a 3144 Hall magnetic sensor

IGBT Transistorised Electronic Ignition using a 3144 Hall magnetic sensor - YouTube


How To Advance Go Kart Engine Timing WITHOUT a Timing Key

How To Advance Go Kart Engine Timing WITHOUT a Timing Key - YouTube


How to find ignition timing on small engines

               How to find ignition timing on small engines - YouTube

Easy Hall Effect Transistor Ignition using a 3144 hall sensor and 2N2907 TIP42C

                 Easy Hall Effect Transistor Ignition using a 3144 hall sensor and 2N2907 TIP42C Transistors - YouTube


Many Many Thanks for the HELP!!!!


----------



## dsage

I understand the typical waste spark system.
I guess my question now would be who cares if it has a wasted spark?
Wasted spark is in fact used on many engines these days. All those with say six cylinders and only three coils are waste spark engines. They don't have any issues with back firing. I would say if the mixture is still at a concentration to fire again when it has already been burned you have an issue with the mixture, ignition timing or valve timing (or other).
And why go to all that complexity to eliminate it. The wasted spark should do no harm and complexity just breeds problems. The simpler the better. Which, I imagine is why they built it like it is.
KISS.
BTW. The last circuit you show above is one I designed and was later improved through a collaboration with John Gedde and I.
It was well documented on this forum. It will work. But you should implement any differences from your drawn circuit. The improved circuit is better.





						A new ignition circuit
					

I'm in Pueblo Colorado. Mountain time zone I believe you are in Central Time Zone and that  would put you 1 hr ahead of me. Your 6 pm would be my 5 pm.  I have two 1N4003 diodes and one  NTE 116 diode.  Also three Q1s and  two Q2s. Also Have spare capacitors on hand. The only thing I don't have...




					www.homemodelenginemachinist.com
				



Post 144
The one drawn on squared paper I would not recommend for a lot of reasons.
Have fun.


----------



## Steamchick

Hi Juan C: The simple (Ha Ha!) solution to eliminating the redundant spark that causes back-fires  on this engine would be to affix the hall effect trigger on the CAM-shaft, not the Crankshaft. - It runs at the half crank speed that you require. Of course, you will have to work out "How" - and "When?" to trigger the spark. Sometimes, the gear on the end of the camshaft is the largest radius for affixing whatever you need for the Hall effect sensor. (a button or a hole?).
K2


----------



## Harglo

Steamchick said:


> Hi Juan C: The simple (Ha Ha!) solution to eliminating the redundant spark that causes back-fires  on this engine would be to affix the hall effect trigger on the CAM-shaft, not the Crankshaft. - It runs at the half crank speed that you require. Of course, you will have to work out "How" - and "When?" to trigger the spark. Sometimes, the gear on the end of the camshaft is the largest radius for affixing whatever you need for the Hall effect sensor. (a button or a hole?).
> K2


I use a small micro switch that stays open till the Hall is ready to close. I fab it up its trip on the exhaust valve to open just as the valve closes there are other places for a switch to be mounted with an adjustable trip arm over the switch lever arm.
Harvey


----------



## Steamchick

I guess the micro-switch could be arranged mechanically to open when exhaust valve is closed while electrically being across the contact breaker   points: (so the electric circuit sees the points opening and sparks) yet when the Cam or  rocker opens the exhaust valve the contacts close in the micro-switch (so the electric circuit does not see the contacts open = no spark).
Seems easy to arrange electrically and mechanically. = clever!
K2


----------



## bluejets

Steamchick said:


> Seems easy to arrange electrically and mechanically. = clever!



Ever heard of switch bounce.......(= not so clever)


----------



## willray

bluejets said:


> Ever heard of switch bounce.......(= not so clever)


I think Steamchick is thinking of having a switch that opens and closes only when the hall effect sensor is already closed - so any bounce on the mechanical switch would be invisible as the hall effect sensor is already conducting.


----------



## bluejets

willray said:


> I think Steamchick is thinking of having a switch that opens and closes only when the hall effect sensor is already closed - so any bounce on the mechanical switch would be invisible as the hall effect sensor is already conducting.


How quick can you open and close a micro compared to a hall effect...?


----------



## willray

bluejets said:


> How quick can you open and close a micro compared to a hall effect...?



Hardly matters.  The OP would like to invent a hall-triggered system that only fires once per 2 revolutions of the flywheel.  A hall sensor on the flywheel can give good resolution for spark timing, but opens (briefly) on every revolution, and OP would like to cancel one of those.

The cam provides a way to identify which spark should fire and which should be cancelled, but lacks the resolution for good spark timing.

So long as the microswitch is fast enough to close after the hall closes on the correct firing, and it's finished bouncing before the hall opens for the (desired to be eliminated) wasted spark, any bouncing on closing doesn't matter.  So long as it opens just after the hall closes from the wasted spark, and it's finished bouncing before the hall opens for the correct spark, any bouncing on opening doesn't matter.

In this design, the microswitch would open and close while the hall is conducting, and it has almost an entire revolution of the flywheel to accomplish reaching a stable state upon opening or closing.  It really shouldn't have a hard time accomplishing that.

Now, I'm with dsage - I don't think it's a tremendously necessary modification - but conceptually, using a low-resolution signal from the cam to short across the hall sensor during the unwanted spark should solve the "problem".


----------



## dsage

Or conversely (I think). The microswitch could be used in series with the signal line from the hall sensor. As long as the microswitch closes (and passes the signal to the ignition system) some time in advance of when it's needed and opens some time after when the signal is not wanted - Job done. No critical timing required. And no bounce to worry about. The switch will be stable for many degrees before it's a problem.
Way too much complexity for me. As I mentioned if you have the conditions necessary for the mixture to fire in the exhaust system there is something not right with the engine.


----------



## GailInNM

One possible problem with microswitchs is the number of operations before failure rating. Typical rating for high quality name brrand switches is 1 million operations. The best high rel switches are about 10 million operations and consumer grade import switches is often only a few hundred thousand if they are rated at all. 

Taking the 1 million  operations, at 1000 rpm the switch will be operated 500 times/minute and that translates into about 30 hours of operation before the switch will need to be changed. If you are only going to run your engine occasionally for only short periods of time this may be acceptable. As I sometimes put 20 hours on an engine at a long weekend of running it would not be for me.

I would use two Hall effect switches. The Hall switches can be in parallel so both have to be actuated, or de-actuated depending on your circuit, for spark to occur. 
Gail in NM


----------



## Kenif

I recently came up on this with a 1940's B31 motorcycle I'm rebuilding.
Try:








						69.85US $ 16% OFF|Universal Dc Cdi Igniter Ignition Switch Modified Motorcycle Bike Atv Scooter Moped Buggy Racing Digital Adjustable Programmable - Motorcycle Ignition - AliExpress
					

Smarter Shopping, Better Living!  Aliexpress.com




					www.aliexpress.com
				



They also do coils and triggers.  The unit has adjustable advance mapping using a laptop or a mobile phone with optional blue tooth adapter. When you purchase the box the supplier will give you a link to the software. I got the software before I bought it to see how good / easy it was / is.
For about AUD$120 delivered, coil was AUD$6 and trigger AUD$2.00  needless to say I bought a couple of spares. It was a good option for me. 
My use is a bit different as old bikes use manual spark control and too much advance at low revs will kill them... So it's now fixed so anyone can ride it!


----------



## Steamchick

dsage said:


> Or conversely (I think). The microswitch could be used in series with the signal line from the hall sensor. As long as the microswitch closes (and passes the signal to the ignition system) some time in advance of when it's needed and opens some time after when the signal is not wanted - Job done. No critical timing required. And no bounce to worry about. The switch will be stable for many degrees before it's a problem.
> Way too much complexity for me. As I mentioned if you have the conditions necessary for the mixture to fire in the exhaust system there is something not right with the engine.


I agree that this ignition problem is just as likely to be a carburation problem = to rich.
I have experienced odd problems on over-run pop-backs on motorcycle engines where the idle was "too much and too rich"... 
K2


----------



## gilbycoath

I don't about model engines but I run race cars and they all run with crankshaft triggers ( wasted Spark ) no problems.
Ron


----------



## Steamchick

Kenif said:


> I recently came up on this with a 1940's B31 motorcycle I'm rebuilding.
> My use is a bit different as old bikes use manual spark control and too much advance at low revs will kill them... So it's now fixed so anyone can ride it!


Hi Kenif: Last B31 I had (1951 model, with a 250 Norton swinging arm fitted instead of the plunger rear end!) was fine with the magneto and manual advance.... I never had any problems, but that was mid-1970s and "old codgers" like me had used so many different bikes at various times, we just got on with it and learned to use whatever controls existed... But Magneto re-builds cost more than your house now...
K2


----------



## CFLBob

"The OP would like to invent a hall-triggered system that only fires once per 2 revolutions of the flywheel.  A hall sensor on the flywheel can give good resolution for spark timing, but opens (briefly) on every revolution, and OP would like to cancel one of those. "  

I've been kind of watching this discussion and wondering if anyone has tried the approach that seems like the obvious answer to me.  A circuit trick to divide a frequency by two requires just one component: a D-type flip flop.  The "generic" part number in logic parts is a 7474.  If you were running this on 12V, you could use a higher voltage logic family, like CMOS, making it a 74C74.






If the "every other" pulse is a problem, this will effectively make it go away.  The only gotcha I see is that this assumes the first one is the one you want.  

Several of you have played with electronic ignitions far more than I have, so I wonder if this is ever used.


----------



## Kenif

Popping exhausts on the over-run can also be a burnt exhaust valve or by an exhaust leak - sucking air into the exhaust and igniting unburnt fuel. On a motor bike I would use a lambda sensor - to test for correct fuel air ratio OR do a "plug chop" - run the engine 'till its hot with a used spark plug with correct gap....  Run at full power for say 15-20seconds shut throttle and stop straight away - do not let it idle.  Plug should be clean and light brown - if its sooty and black - to rich, if its oily black - bad rings or guides.  If its white to lean. There are good articles by "Gordon Jennings" on "How to read spark plugs". The spark plug will tell all....


----------



## 74Sprint

What is sorely lacking here to fire once per 720 degrees is synchronization of the compression stroke. The ignition would need some way to know when an engine is on a compression stroke. One could use 3 Hall-effects, one for each rocker or push-rod and one on the crank. Then connect them to a 3 input 'AND' gate. This way when both rockers are at rest you know a compression stroke is about to happen and when the crank signal happens it fires the ignition.  This setup however would mean adjusting the timing manually. One could also use the embedded magnet built into the flywheel for a crank signal. Or use the cam gear and crank flywheel. But in all reality wasted spark helps to keep the sparkplug clean and there are millions and millions of engines out there for years using it.

Side Note:
I have done a lot of testing of small engine ignitions and I can tell you right now that Walbro makes the worst. Ever hear of the Pulling-Poulan chainsaws and other Poulans? The reason they call them Pulling-Poulans which is now owned by Husqvarna and they now both use one type of Walbro ignition that is designed to reduce kick-back when starting. So you end up pulling and pulling to get the damn thing to start. What Walbro does is put everything into a single coil pack and it is considered a high voltage (@220Vac) CDI preprogrammed ignition. Now to be nice to the person trying to start one of these engines they retard the timing between 0 and 8 degrees ATDC. So it fires when the piston is going down already. I have 3 engines now that will either not start but make flames out the exhaust or they just slowly die. According to Walbro information it is very common on this type to retard timing 8 degrees ATDC and only start to increase timing once the engine reaches 450- 500 RPM which is nuts, it should be 200 RPM. Now I don't know the brand of ignition coil shown in the pictures but I suspect it's a Walbro. I've tried changing coil packs both OEM and even Chinese made ones with no luck. I've had some success increasing the gap between the coil and flywheel which increases timing but there was not enough adjustment. Increase the gap too much and I loose spark. The only thing I can think of is that when the flywheel is made there is core shift or something and the magnet is not positioned correctly, so need new flywheels.

Sorry I haven't been contributing much lately but business calls and prep for winter. I hope to get more done after Xmas.

Ray


----------



## JuanC

CFLBob said:


> "The OP would like to invent a hall-triggered system that only fires once per 2 revolutions of the flywheel.  A hall sensor on the flywheel can give good resolution for spark timing, but opens (briefly) on every revolution, and OP would like to cancel one of those. "
> 
> I've been kind of watching this discussion and wondering if anyone has tried the approach that seems like the obvious answer to me.  A circuit trick to divide a frequency by two requires just one component: a D-type flip flop.  The "generic" part number in logic parts is a 7474.  If you were running this on 12V, you could use a higher voltage logic family, like CMOS, making it a 74C74.
> 
> View attachment 131847
> 
> 
> If the "every other" pulse is a problem, this will effectively make it go away.  The only gotcha I see is that this assumes the first one is the one you want.
> 
> Several of you have played with electronic ignitions far more than I have, so I wonder if this is ever used.


Dear Bob, Yes that is the idea I am pondering to use.  I got it on another forum called "All about circuits".  With the D FF and the circuit from John I think I am all set!  I just need to figure out how to solder things...LOL  
  I will let you know if I need some more help once I start putting it together.
Thanks for the help!


----------



## CFLBob

JuanC said:


> Dear Bob, Yes that is the idea I am pondering to use.  I got it on another forum called "All about circuits".  With the D FF and the circuit from John I think I am all set!  I just need to figure out how to solder things...LOL
> I will let you know if I need some more help once I start putting it together.
> Thanks for the help!



After I posted that, I started to wonder if that would be useful in an ignition.  

The difference is that we're dealing with short pulses and high voltages in electronic ignitions and every time I've used that circuit was for square waves that were on half the time (like in the figure I got offline).   Designing for pulses is different than designing for 50% on, 50% off square waves, and designing for spark plug pulses is even more different.

Yeah, I can see how to turn that square wave into a pulse again, using it to trigger another part (74C123), but I have no idea if these things really work in ignition systems.    

I'll be interested in seeing if it works for you, Juan.


----------



## willray

CFLBob said:


> I'll be interested in seeing if it works for you, Juan.



I'll be astounded if we see that it works (interested too, but astounded nonetheless!).

I don't believe that the square-wave/equal-time issue is any kind of a problem for the flip-flop solution, or at least whatever variety of problem it may be, is dwarfed by the facts that :

A) the thing cannot know which of the two sparks it needs to quench, and B) with spark voltages flying around, it will be exceptionally difficult to keep the TTL/CMOS/etc-level flip-flop logic from seeing spurious triggering events.

Anything that can deal with (A), by definition knows which spark needs to be quenched, and therefore can be used to directly quench that spark, rather than playing counting games.

Efforts to deal with (B) strike me as likely to be brittle.  I would put folding money on the table that even if one can gets it running stably one day, if the humidity changes, it's back to square one.  Someone who does not currently know how to solder, is likely to find that, shall we say, frustrating...


----------



## CFLBob

willray said:


> I don't believe that the square-wave/equal-time issue is any kind of a problem for the flip-flop solution, or at least whatever variety of problem it may be, is dwarfed by the facts that :
> 
> A) the thing cannot know which of the two sparks it needs to quench,



I think that can be set by the person installing it.  We have the ability to see which state the engine is in, so we put the spark plug out where we can see it, and position the sensor such that it fires at the end of the proper stroke.  



willray said:


> B) with spark voltages flying around, it will be exceptionally difficult to keep the TTL/CMOS/etc-level flip-flop logic from seeing spurious triggering events.



I was surprised when I bought my electronic ignition for my Webster that it was in a plastic box and not metal for that reason.  Shielding is important in just about anything these days.  Especially something like this.


----------



## willray

CFLBob said:


> I think that can be set by the person installing it.  We have the ability to see which state the engine is in, so we put the spark plug out where we can see it, and position the sensor such that it fires at the end of the proper
> Stroke.



That only works if you’re willing to pull the plug to reindex the spark, every time you pull the starter.  Since the impulse for the spark is created every time the magnet passes the coil, and small engines have plenty of “bounce”, you’ll see many instances of the magnet passing the coil that do not correspond to rotations of the crankshaft.  This blows any chance of “index it today, use it 10 minutes from now” actually working reliably.


----------



## willray

willray said:


> Someone who does not currently know how to solder, is likely to find that, shall we say, frustrating...



I should also say, there is absolutely nothing wrong with not currently knowing how to solder, and I applaud anyone who has an interest in learning how to solder and usefully manipulate the pixies. My hat is off to the OP for having the gumption to tackle the project.

my comment is _solely_ that this kind of project does not make for a pleasant learning experience.  I’ve had a student spend 2+ years in the lab chasing apparent spurious triggering faults in a hall-sensor system, all as the result of a poorly regulated switching supply dumping just enough noise into a shift buffer to make it look like sensors that weren’t, were.

down this particular road, I expect hair pulling.


----------



## 74Sprint

I agree with willray on this one. Without some electronic-mechanical way of knowing when on the compression stroke there is no way to sync the ignition to the compression stroke other than manually. That is the reason 4 stroke engines use a cam sensor for synching the ignition. Spurious noise can be filtered out but, there is a bigger problem with when the ignition fires and that is the huge negative going (below zero volts) part of the coil firing/ringing. Most TTL stuff does not like seeing -100 volts and tend to get punch-through blowing the TTL. CMOS is better and can survive more but if not protected they too can get punch-through, either shorting them for a short time or opening them up, been there, done that.

Since JuanC has 12 volts available the easiest thing to do would be to use the LS coil ignition I presented in post #124. It (the circuit) has a very hot spark and it has some immunity to noise including from the spark. It however has fixed timing, so timing would have to be manually adjusted when running and without synching it would be wasted spark. It is a very simple circuit to solder up. Without synching and using a 'D' flip-flop along with a switching Hall-effect one would have to bring the engine up on compression stroke each time when starting before turning the ignition on. 

IMHO I think this would be a good learning example of what not to do but, got to start somewhere. I just can't see why someone would want to reinvent the wheel.

Ray


----------



## Eccentric

I am working on my electronic ignition for my twin cylinder 4 stroke.  Here I am using a DC motor with a magnet mounted on a collar triggering a hall sensor--this simulates the setup on the engine.  I will use a magnet mounted to the crank and fire both spark plugs at the same time, ie wasted spark.  I will use a little microcontroller to adjust the timing advance from 5 to 25 degrees before top dead center depending on the RPM.  The circuit board has the analog circuitry that converts the hall sensor output to a nice 1 millisecond pulse, and then another transistor stage that will drive the coil over plug (COP)s from a signal generated by the microcontroller.  The pulse to the COPs will be 4 millisecond in duration.  This will diminish if the RPMs get high enough to not exceed a 50% duty cycle on the COP trigger signal.


Below is a scope trace of a couple of key signals in the analog circuitry.  The green is the signal generated by the RC circuit triggered by the hall sensor, and the yellow is the pulse on the output of the NPN transistor, the RC time constant is set for a 1 millisecond pulse.





Below is the DC motor setup to simulate the hall sensor on the engine.  I can control the motor speed by adjusting the voltage is sees.





Next up is wiring the COPs and the sparkplugs.  We will see what EMI havoc is caused by the high voltage travelling through the sparkplug wires.


----------



## 74Sprint

Well for starters those are Coil Near Plug (CNR) coils, no biggy.
I've been real busy lately and have not done much but work on business stuff and working on my patent that has nothing to do with ignitions. But 3 future ones will. I'm just getting back into my ignitions so I'll be doing some updates soon.

It seems that you are doing something similar to me, except I'm going to be using a Arduino Nano for the processor and build for a 1-8 cylinder ignition. Nice part of using a micro-processor to adjust the dwell is you can find out how fast the coil circuit charges and discharges which leads you to finding out how much dwell time the coils need, get max spark without over heating them or the transistor/s.

A few of things to watch for:
- The Hall-effect board you are using should have the actual Hall-effect glued to the board otherwise the Hall-effect will eventually break off from engine vibrations. Also if the Hall-effect vibrates it will throw off the timing, jittery.
- The distance between the Hall-effect and magnet will change the timing. As will the magnet strength and the parameters of the Hall-effect.
- All coils are wired for their expected parameters. Such as CDI coils are generally high-voltage/low current input, Kettering/points are wattage ie. lower voltage but higher current, and magneto coils are high resistance to convert some of the high current into driving voltage. This is all based on the input to the primary coil side.
- The Arduino U3 and the Nano are somewhat slow by todays standards but, that does not mean they can't be used below 10,000 RPM, just don't load them up with to much work to do like serial coms.
- For the Arduino use one of the interrupts to receive the Hall-pulse, so it calculates the timing unbothered. 
- For better success use something like the BU941, it is designed for driving ignition coils. There are others that will work at lower voltage, just need to Google for ignition transistors or ignition drivers.
- Most coils I have used come in @ 2.5 msec for dwell.

I have 1 more project I need to finish before getting back on the ignitions but, after that I can share with you my code that I already have and will approve upon. I have the interrupt, RPM calculations, storing and reading the lookup tables for ignition timing, dwell pulse length, and serial coms to LCD display (just RPM & Timing), and temperature done. I also have the PC side of things started, I just need to put it all together.

Good luck
Ray


----------



## Eccentric

Ray,

I will be using a UNO for my microcontroller, actually I will just be using the ATmega328P chip on my own board.  It sounds like your code is more advanced than my version.  I use two interrupt routines, one triggered by the hall sensor which starts a timer for the pulse width and a second interrupt from the timer to create the pulse to the COP.  I use two timers, one as mentioned to control the timing of the final output pulse and its width and thus the dwell and then another used to calculate the RPM.  my main loop does the RPM and advance/retard calculation/lookup and outputs to the LCD display.

I would be happy to give your code a run when it is ready, and I'd be happy to share mine.  Measuring temperature is an interesting idea.


----------



## 74Sprint

Sounds like you and I are doing almost the same build. I'm using the Nano right now just for development and will be doing the same as you but I will be using the ATmega32U4, basically the same but more interrupts. I wrote a program in VB6 to work with the PIC12F1840 and need to convert it to C# for loading in the the stored values and timing values. I also did some programs to time how long the EEPROM read takes and some calculations (Excel) for pulse width to RPM. But because the magnet and Hall-effect I'll/we use, will have to calibrate the ignition timing. I have all this stuff but, I have to find it again LOL. My RPM, look up values, pulse width(dwell), and timing ignition delay are all in the interrupts, the RPM and temperature/LCD are in the main loop. Temperature sensor is the DS18B20. It's small enough to glue in the fins or water jacket and has it's own testing with a report of problems. Cold engines are a PITA until warmed up.

When I do the PC program C# conversion I'll be looking forward to your feedback on the program. I'm thinking tic marks of every 250 or 500 rpm, I could do 100 even, the EEPROM has enough room. Or I was thinking of maybe doing what we did with the 1840 RC-ignition and use 2 lookup tables for timing that can be changed on the fly.

I'm also making a lot more advanced ignition for my race car that is distributorless, with MAP sensor (boost 1 to 3 bar), temperature, and sequential ignition 4-30 cylinder. But for this I'll be using a STm32. Well that's about it until I find more time.

Cheers
Ray


----------



## Bentwings

74Sprint said:


> Sounds like you and I are doing almost the same build. I'm using the Nano right now just for development and will be doing the same as you but I will be using the ATmega32U4, basically the same but more interrupts. I wrote a program in VB6 to work with the PIC12F1840 and need to convert it to C# for loading in the the stored values and timing values. I also did some programs to time how long the EEPROM read takes and some calculations (Excel) for pulse width to RPM. But because the magnet and Hall-effect I'll/we use, will have to calibrate the ignition timing. I have all this stuff but, I have to find it again LOL. My RPM, look up values, pulse width(dwell), and timing ignition delay are all in the interrupts, the RPM and temperature/LCD are in the main loop. Temperature sensor is the DS18B20. It's small enough to glue in the fins or water jacket and has it's own testing with a report of problems. Cold engines are a PITA until warmed up.
> 
> When I do the PC program C# conversion I'll be looking forward to your feedback on the program. I'm thinking tic marks of every 250 or 500 rpm, I could do 100 even, the EEPROM has enough room. Or I was thinking of maybe doing what we did with the 1840 RC-ignition and use 2 lookup tables for timing that can be changed on the fly.
> 
> I'm also making a lot more advanced ignition for my race car that is distributorless, with MAP sensor (boost 1 to 3 bar), temperature, and sequential ignition 4-30 cylinder. But for this I'll be using a STm32. Well that's about it until I find more time.
> 
> Cheers
> Raycustom model ignitions have always been a challenge . I’ve had at least half a dozen after market ones , some worked some did not . Some engines had magneto ignitions these were the least troublesome  the key was to turn the engine fast enough to get the first spark . I flew my big Corsair in a rain squall I was worried the engine might stall from the moisture. I YHINK it ran hot enough for the water to boil off.


----------



## 74Sprint

Well I finally found some time to do more work on my programmable ignition and made a little movie showing the Hall-Effect frontend. Hall-Effect Frontend Movie I still don't have my 3D printer setup so I just used some wood blocks to mount the Hall-Effect. I also placed the DC motor in the the bottom wood block and it spins a CD disc that has a 360 degree CD label on it. 





As you can see I hot glued the disc to they motor drive. The drive came from an old CD drive that was B/O. The drive wheel has a machined surface already that centers the disc. I epoxied 2 magnets on the bottom to keep it in balance. I guess I could have used something else to balance it out with just 1 magnet but, this should work. I did spin this up to 413Hz. but because of the 2 magnets I have to divide that by 2 to get RPM. So 206Hz is about 12,000 RPM, 206x60 = 12,360 RPM. I lost my nerve to take it any higher with this setup.  The magnets are placed at 60 and 240 degrees, the 60 degrees of rotation should give the Nano enough time to do the calculations for 36 degrees of timing advance. Of course all of this depends on the strength of the magnet, Hall-Effect used, and the distance between them. As I show in the movie this setup of mine shows the on/off points have a 10 degree field of sweep, 55-65 & 235-245. This can be compensated for in the firmware code. And yes I know that the magnets are on the face of the flywheel instead of on the edge but, the motor is sitting vertical so the armature movement is very stable.

If you look at the "Hall-Effect Frontend.pdf" you'll see that the circuit is quite simple. If you use the same Allegro Hall-Effect that I used (A1102) then they say that C1 & C2 are not required but, I like lots of filtering. If you run a lot of sustained high RPM then the 2N4403 may get a bit hot, so just increase the value of R1 (2.5k-10K). The way the frontend circuit is setup right now it will work with a LS1 or LS2 coil but, high RPM maybe limited because of the lack of dwell timing. The frontend circuit can operate on 12 volts, the same as the coil. When the Hall-Effect senses a South Pole it turns on and it's output goes to ground(-) so it puts out a negative pulse. The 2N4403 PNP converts this to a positive pulse. The inline LED between the Hall-Effect's output and the base of the 2N4403 supplies biasing. I should mention that transistors are current devices and FETs and MCUs are voltage devices. What I mean by this, is that transistors with proper voltage biasing have a current (amperage) gain, where as FETs and MCUs are voltage controlled or sensing. One problem with FETs is the gate voltage, to turn it off the voltage has to go to ground or negative level to turn off. This is where gate drivers come into play. Yes I know FETs are great at conducting a lot of current but, it's the gate voltage and not the current that controls it. Transistors need current flow through the base a lot more than FETs need gate current. When I get the MCU programed and hooked up I'll add a timing light (LED) on the frontend to show the firing signal and it's timing on the degree wheel. I believe that this frontend represents about 10% of the work required for my programmable ignition.

Cheers
Ray


----------



## Eccentric

Looking good Ray, I will take a look at your circuit. I agree with your statement about lots of filtering on power as close to the part as you can get it.  I think 12,000 RPM is plenty fast enough   .  I have about 9 degrees of sweep given the radius of the magnet on the flywheel, close to your value.

Are you going to use a timing light?  I used to have one years ago, but no longer.  I really don't want to buy another one, but it sure would be handy to see what is acually going on when running at speed.

I have been working on mounting the hall sensor to the engine.  In the picture below you can see the magnet embedded in the flywheel, highlighted by the red circle.  I have my Arduino Uno code running to a certain extent, I have the interrupts working and I have two 2048 lookup tables in program memory, one for the time to fire the spark and the other for the RPM value.  I take the number of ticks it for a full revolution shifted right by two for the index into the lookup tables.


----------



## Bentwings

74Sprint said:


> Well I finally found some time to do more work on my programmable ignition and made a little movie showing the Hall-Effect frontend. Hall-Effect Frontend Movie I still don't have my 3D printer setup so I just used some wood blocks to mount the Hall-Effect. I also placed the DC motor in the the bottom wood block and it spins a CD disc that has a 360 degree CD label on it.
> View attachment 136040
> 
> 
> As you can see I hot glued the disc to they motor drive. The drive came from an old CD drive that was B/O. The drive wheel has a machined surface already that centers the disc. I epoxied 2 magnets on the bottom to keep it in balance. I guess I could have used something else to balance it out with just 1 magnet but, this should work. I did spin this up to 413Hz. but because of the 2 magnets I have to divide that by 2 to get RPM. So 206Hz is about 12,000 RPM, 206x60 = 12,360 RPM. I lost my nerve to take it any higher with this setup.  The magnets are placed at 60 and 240 degrees, the 60 degrees of rotation should give the Nano enough time to do the calculations for 36 degrees of timing advance. Of course all of this depends on the strength of the magnet, Hall-Effect used, and the distance between them. As I show in the movie this setup of mine shows the on/off points have a 10 degree field of sweep, 55-65 & 235-245. This can be compensated for in the firmware code. And yes I know that the magnets are on the face of the flywheel instead of on the edge but, the motor is sitting vertical so the armature movement is very stable.
> 
> If you look at the "Hall-Effect Frontend.pdf" you'll see that the circuit is quite simple. If you use the same Allegro Hall-Effect that I used (A1102) then they say that C1 & C2 are not required but, I like lots of filtering. If you run a lot of sustained high RPM then the 2N4403 may get a bit hot, so just increase the value of R1 (2.5k-10K). The way the frontend circuit is setup right now it will work with a LS1 or LS2 coil but, high RPM maybe limited because of the lack of dwell timing. The frontend circuit can operate on 12 volts, the same as the coil. When the Hall-Effect senses a South Pole it turns on and it's output goes to ground(-) so it puts out a negative pulse. The 2N4403 PNP converts this to a positive pulse. The inline LED between the Hall-Effect's output and the base of the 2N4403 supplies biasing. I should mention that transistors are current devices and FETs and MCUs are voltage devices. What I mean by this, is that transistors with proper voltage biasing have a current (amperage) gain, where as FETs and MCUs are voltage controlled or sensing. One problem with FETs is the gate voltage, to turn it off the voltage has to go to ground or negative level to turn off. This is where gate drivers come into play. Yes I know FETs are great at conducting a lot of current but, it's the gate voltage and not the current that controls it. Transistors need current flow through the base a lot more than FETs need gate current. When I get the MCU programed and hooked up I'll add a timing light (LED) on the frontend to show the firing signal and it's timing on the degree wheel. I believe that this frontend represents about 10% of the work required for my programmable ignition.
> 
> Cheers
> Ray or work now use your self powered timing light or use battery for batter power on and record timing go from idle to full throttle . I did a similar thing by using a plat that held he magnet. The plate was slotted so I could adjust initial timing then check to see if there was built in timing . I plotted on grah paper at first then graduated to excell graph . The electronic units I had did not change from initial setting from as low idle speed I could get to full speed so it was easy to change timing over several different engines go small boers 28 deg total seemed the best for overall performance  my original mech advance on one engine fit not work very well . I replaced several magneto ignitions and just used 28 total . It made starting much easier as magneto engines needed a very sharp flip of the prop to generate enough spark . The electronics were just a quick flip as you were going . Assuming the carbs are adjusted reasonably close . Large bore automotive engine seem to like a little more or less dvance depending on load and speed . It also has to do with compression ratio  super charging affects it too .
> Byron


----------



## 74Sprint

Eccentric said:


> Looking good Ray, I will take a look at your circuit. I agree with your statement about lots of filtering on power as close to the part as you can get it.  I think 12,000 RPM is plenty fast enough   .  I have about 9 degrees of sweep given the radius of the magnet on the flywheel, close to your value.
> 
> Are you going to use a timing light?  I used to have one years ago, but no longer.  I really don't want to buy another one, but it sure would be handy to see what is acually going on when running at speed.
> 
> I have been working on mounting the hall sensor to the engine.  In the picture below you can see the magnet embedded in the flywheel, highlighted by the red circle.  I have my Arduino Uno code running to a certain extent, I have the interrupts working and I have two 2048 lookup tables in program memory, one for the time to fire the spark and the other for the RPM value.  I take the number of ticks it for a full revolution shifted right by two for the index into the lookup tables.


We must be using a similar magnet & Hall that have similar specs, the magnet looks about the same size as mine. I have my Hall mounted 3.5mm/0.138" away from the disc and the disc is 1.2mm thick. I have a person that wants one of these ignitions for his racing motorcycle a 2 stroke but, he needs 14,000 RPM. Which means the magnet I'm using now is to wide, so I have to buy some small diameter cylindrical magnets for testing later. I think a 5 degree sweep would be ok. 

As for the timing light I'm just going to use 1 of the LEDs that I have. They are the same as what Cadillac uses for brake lights, these suckers are very bright but, red. I'll just mount it above the pointer and go off the shadow it casts. I have 2 schematics of the circuits if your interested, it uses a 9 volt battery but, they are in German and some English.

I also have to admit that going your way of measuring the time between pulses is a lot easier than using the pulse width to do the timing. All the other engine ignitions and with everyone else I worked with used the time between pulses. One thing I haven't done yet is find my old code or order bearings for my engine. And now I have 2 computers to do before next Thursday, having some surgery done. So I'm not going to get much done on this project for awhile. I plan on porting my old MicroChip code to Arduino code and get that working. I also just started getting the C# program going to program the Nano through the USB port for the EEPROM timing tables. No doubt you'll most likely be done for me.

I did measure my pulse widths this morning but that cheap motor controller isn't steady at all below 600 RPM, it sucks. The pulses decrease by half when the RPM doubles, so it is nice and linear, math equation should not be too complicated. LOL. The way you are going with the code seems correct, shifting and all.

Cheers
Ray


----------



## bluejets

74Sprint said:


> but, he needs 14,000 RPM



Seem to remember this type of thing with the 508 ic way back when.
Someone Always wants it higher revs.
One option that you might be able to apply is mount the magnet on the back of the hall effect and use a slotted metal disc or similar.


----------



## stevehuckss396

Instead of thinking in terms of RPM, think in sparks per minute. For guys like myself who build multi cylinder engines sparks per minute is easy to deal with. For a v8 or a 9 cylinder radial to run at a decent Rpm the sparks per minute may need to be in the 20 to 30 thousand range.


----------



## TonyM

Slightly off topic. But can an ignition circuit be judged by the ability of a spark to jump a certain gap in air. So for example if a spark jumps 10mm in air is it likely to be OK under compression say 6 or 7 to 1


----------



## payner

TonyM . Yes that was my thought, years ago I did small engine repair and was thinking the same thing also if the spark is jumping a bigger distance it is easier to see if you have a good blue spark or a weaker yellowish spark . If the spark is nonexistent or yellowish then you knew to dig deeper to solve the problem.
Bill


----------



## Eccentric

TonyM said:


> Slightly off topic. But can an ignition circuit be judged by the ability of a spark to jump a certain gap in air. So for example if a spark jumps 10mm in air is it likely to be OK under compression say 6 or 7 to 1




There is a well-known expression known as "*Paschen's Law*" relating spark gap to pressure and potential. Performing a little tweaking on the constants there is a linear model. The relation for gas composition air is:



*V = 4.3 + 136 × (p / T) + 324 × (p / T) × Dg*​


*V* = voltage potential (kV)
*p* = absolute pressure in Bar
*T* = gas temperature (Kelvin)
*Dg* = electrode gap in mm


----------



## 74Sprint

bluejets said:


> Seem to remember this type of thing with the 508 ic way back when.
> Someone Always wants it higher revs.
> One option that you might be able to apply is mount the magnet on the back of the hall effect and use a slotted metal disc or similar.



Ain't that the truth. My little CDI Sparky is capable of doing 50,000 RPM on a single cylinder but, then again that's using a 12 volt battery. I have thought about the window wheel.



stevehuckss396 said:


> Instead of thinking in terms of RPM, think in sparks per minute. For guys like myself who build multi cylinder engines sparks per minute is easy to deal with. For a v8 or a 9 cylinder radial to run at a decent Rpm the sparks per minute may need to be in the 20 to 30 thousand range.



This is where the CDI ignition is nice. It can fire at a higher RPM than a standard inductive ignition because the CDI can be charging all the time. As I mentioned above my Sparky ignition can do 50,000 RPM on a single cylinder but, yah divide that by 8 for an 8 cylinder and now it's limited to 6K-7K range. It can go higher with a different coil, lower primary voltage, or higher battery voltage. The 50,000 RPM is with the custom coils I had made. Problem with CDI ignitions is with the coils they use which, usually stop working once the primary voltage goes below 120 volts. My Sparky starts off at 1,000-1,100 volts primary.



TonyM said:


> Slightly off topic. But can an ignition circuit be judged by the ability of a spark to jump a certain gap in air. So for example if a spark jumps 10mm in air is it likely to be OK under compression say 6 or 7 to 1



No, because of how transformers/coils (same thing) work, one also has to consider the amount of sparkplug gap and the fuel being used. For example; magnetos are considered low voltage high current and are used almost exclusively with LL100/110 8:1 compression aircraft engines which are also centrifugal supercharged, think DC3 radials. At 18 inches of manifold pressure that equates to 17:1 compression at higher RPM and they still work fine. The standard inductive (points) is considered medium voltage medium current and we know how well they work. CDI are considered high voltage low current, you put more current in trying to charge the capacitor than you get out (the caps ESR resistance is limiting). Magnetos do not put out any voltage it's just a current generator, the voltage is created by the high resistance of the transformers primary. When it comes to inductive ignitions companies have always played around with the coil resistances and point material to get a stronger spark, like Accel and their super coils, tough on points. CDI is a similar story as inductive. So back to your original question. How the coils work is they have a high initial current flow under high starting voltage @12v for inductive and 200-1,000v for CDI. That initial high current flow causes a high voltage in the secondary but and I mean but, as soon as an arc across the plug gap happens the coil's secondary is shorted out. When this happens all the excess voltage is converted into current. You need high voltage to jump the gap but, you need current to burn the fuel. Both air and fuel are both dielectrics, so you need a spark strong enough to punch through them to cross the gap. So now the type and octane of fuel comes into play. Low octane fuels are easier to punch through.

Anyway using that compression range and regular fuel say 87 octane you should be fine with a 10mm spark. In fact a lot of engines using that much compression get away with just a 10Kv spark.

Cheers
Ray

P.S. I have some charts, research papers, and thesis papers on spark, spark voltage and combustion if your interested.


----------



## stevehuckss396

That would be tough. There is more to it than than just compression. A lean or rich condition can factor in also. I think a number of sparks per minute with a specific amount of energy joules? Enough energy to achive ignition. I think 74 would be better qualified to speak to what that level of energy would be.


----------



## 74Sprint

stevehuckss396 said:


> That would be tough. There is more to it than than just compression. A lean or rich condition can factor in also. I think a number of sparks per minute with a specific amount of energy joules? Enough energy to achive ignition. I think 74 would be better qualified to speak to what that level of energy would be.


Your right Steve about the air/fuel mixture. Also I forgot to mention the Joules, I prefer to use watts though, more people understand watts it seems.


----------



## CFLBob

74Sprint said:


> Your right Steve about the air/fuel mixture. Also I forgot to mention the Joules, I prefer to use watts though, more people understand watts it seems.



Worst joke in high school physics 50+ years ago:  "What's a joule per second?"  "Yes!  Yes it is."   1W = 1J/sec is an easy one to remember.  

Sorry.


----------



## 74Sprint

CFLBob said:


> Worst joke in high school physics 50+ years ago:  "What's a joule per second?"  "Yes!  Yes it is."   1W = 1J/sec is an easy one to remember.
> 
> Sorry.


LOL I hear yah.

Ray


----------



## TonyM

Thanks guys. 
My question was really about how those of us without too much electronic knowledge and test equipment can tell if our ignition system is likely to be working under compression. I have a half decent multimeter but cant measure the kV output. (CDI)
We can all see a spark outside the engine and I wondered if there is a way to judge whether it is likely to be sparking inside the engine based on the maximum spark gap achievable and the compression ratio of the engine.
 Using the formula Eccentric posted, at 1bar and 20C I get a good strong spark at 6.5mm gap. I work that out to be about 11.9kV.  I also worked out that at 6bar and a 0.5mm gap I would need 10.6kV 
 I am only thinking of low compression engines.  4:1 to say 6:1 compression ratios. I guess it's try it and see but it seems like I am in the ball park.
Thanks for the help.


----------



## dsage

DO NOT test your ignition systems by making them jump a large gap. You could damage the coil with an internal spark. The damage may not be apparent but when it is called upon to deliver it will continue to fail internally instead of delivering a spark. at the plug.


----------



## minh-thanh

TonyM said:


> But can an ignition circuit be judged by the ability of a spark to jump a certain gap in air. So for example if a spark jumps 10mm in air is it likely to be OK under compression say 6 or 7 to 1


 
That's how I tried with the igniter
  10mm distance is fine enough with all my engines.



dsage said:


> DO NOT test your ignition systems by making them jump a large gap. You could damage the coil with an internal spark. The damage may not be apparent but when it is called upon to deliver it will continue to fail internally instead of delivering a spark. at the plug.


 
Few sparks at 10mm distance and only first try with homemade igniter or any igniter it's very hard to affect  coils. ( And of course, with commercial ignition circuits there is no need for this )
  And when I know it's ok I won't need to try again.


----------



## 74Sprint

TonyM said:


> Thanks guys.
> My question was really about how those of us without too much electronic knowledge and test equipment can tell if our ignition system is likely to be working under compression. I have a half decent multimeter but cant measure the kV output. (CDI)
> We can all see a spark outside the engine and I wondered if there is a way to judge whether it is likely to be sparking inside the engine based on the maximum spark gap achievable and the compression ratio of the engine.
> Using the formula Eccentric posted, at 1bar and 20C I get a good strong spark at 6.5mm gap. I work that out to be about 11.9kV.  I also worked out that at 6bar and a 0.5mm gap I would need 10.6kV
> I am only thinking of low compression engines.  4:1 to say 6:1 compression ratios. I guess it's try it and see but it seems like I am in the ball park.
> Thanks for the help.


There is a early type of ignition, (low tension ignition) for low compression engines that was used before transformers and it consists of just a single winding coil around a iron bar you can make yourself. It works on the fact that current wants to keep flowing in one direction. You know the spark you see when you unplug something from the wall socket, well this works on the same principle and there is a thread on here on how to make and use one. What's neat about it is that you actually put the contact points in the combustion chamber to ignite the air/fuel mixture. Like a magneto the current meeting a high resistance in this case the gap, creates the high voltage to cross the gap but, the points need to open rapidly. Search on this forum for "low tension ignition".

Ray


----------



## 74Sprint

Complicated ??? yah sort of. Ok it is. But we are talking about a programmable ignition that replaces a mechanical advance.

Well it took a bit of time but, this is the formula I came up with to convert _MY_ pulse width into RPM it's not exact but, very close. This formula works with _MY_ setup but, it can be made to work with other pulse widths. I'm showing this not to be a smart a*s but, to show that using just the pulse width is not easy. If I were to use the time between pulses it would be a lot easier but, the engine can only fire after 1 revolution has been completed. For example; modern car engines will not fire until it sees a cam pulse to synch with the crank trigger, so that can mean 1 revolution or less and fires on the second revolution .

T = pulse width in micro-seconds.





or ((1/(T*0.327))/60)/100 = RPM

Using the time between pulses would be:
T = seconds.





or (1/T) x 60 = RPM

As you can see the "between pulses" is easier. Once one has the RPM and time one can figure out the number of degrees being covered in a certain amount of time and then you can calculate the delay needed for your ignition timing. In other words how fast are the degrees flying by.

In either case if one is using the leading edge of the pulses then the start time never changes. In my case it will always be 55 degrees BTDC regardless of the RPM. It's the same as setting timing with points. If you set points to open at say 22 degrees BTDC it will always be 22 degrees regardless of the RPM. From here one can use time either in micro-sec or milli-sec or clock pulses to count down to firing the coil. Of course the micro-controller code is more complicated than what I have mentioned here but, I just wanted to give an insight into the complexities of the behind the scenes stuff. When I'm finished all one would have to do is enter in when the Hall-Effect sees the magnet in degrees BTDC, set dwell time (these are done only once), and select/set the timing table and then click on the upload button.

Cheers
Ray
P.S. I like math.


----------



## bluejets

TonyM said:


> My question was really about how those of us without too much electronic knowledge and test equipment can tell if our ignition system is likely to be working under compression.


As Ray says, he is playing with advance retard, the actual spark generation is already taken care of.
If you use a standard run-of-the-mill ignition coil with the recommended voltages, deciding if you have enough spark inside is not a concern.
Actually in some instances because of model use, too high a HV can be more of a concern as it will tend to jump everywhere except where it is supposed to.


----------



## 74Sprint

Here is a story about spark strength. I was laid off during the winter of 94/95, being bored I decided I needed a hot ignition system for my race car. So using what I learned about RADARs I made a mega induction HEI ignition, the stock ignition did work fine. This sucker charged the coil at 48 amps and put out a spark of close to or at 100,000 volts, my test equipment rig could only go to 100,000 volts and it sometimes went off that scale. My race car has 11:1 compression so I wanted to see what would happen if I cut off the ground electrode, 0.125" gap now. What the hey it ran but, stumbled when I hit the gas. So I put new plugs in it set for 0.075" gap and tried to go down the drag strip under full load with 100 octane fuel. Well my brand new 8.8mm solid copper core Accel wires had holes blown through them to the closest ground the spark could find. Where ever it blew through there was a small white ash mark. 45Kv was ok at 0.045" gap but not 100Kv at 0.075" gap. Were talking about an ignition that can make 12" sparks across a wooden table top. So can you have to much spark? You bet you can. Oh this ignition would not work on  9.0:1 or higher Hemi head engines, right through the boot. You also could not run an engine for more than 15 minutes without over heating the ignition coil, Accel super coil.

With around 150 years of development of ignition systems, history can teach us a lot, if we know where to look. There are a bunch of ignitions on this forum running on a bunch of different engines so look around for an engine that's something similar to what you have.

Cheers
Ray


----------



## Gedeon Spilett

relating to the Paschen law quoted above, I did a little test to see the spark while increasing air pressure with a syringe.
and yes, the spark was much brighter upon pressure increase...
but I don't have any way to measure these high voltage !








						New video by Francois-Marie Meunier
					






					photos.app.goo.gl


----------



## minh-thanh

Gedeon Spilett said:


> relating to the Paschen law quoted above, I did a little test to see the spark while increasing air pressure with a syringe.
> and yes, the spark was much brighter upon pressure increase...
> but I don't have any way to measure these high voltage !
> 
> 
> 
> 
> 
> 
> 
> 
> New video by Francois-Marie Meunier
> 
> 
> 
> 
> 
> 
> 
> photos.app.goo.gl



An interesting experiment. but i really don't understand
  As far as I know, the compressed air mixture in the cylinder (air and fuel)  is the resistance.

Just speculation, it looks like you increase the pressure - but not  much - and this increases the gas molecules per volume, and it leads to easier ignition.


----------



## mcostello

Years ago I built a high voltage coil from a Radio Shack (remember them) kit. It did improve the idle quality. I happened to brush My hand across a plug wire while the engine was idling and woke up laying on the ground.


----------



## 74Sprint

minh-thanh said:


> An interesting experiment. but i really don't understand
> As far as I know, the compressed air mixture in the cylinder (air and fuel)  is the resistance.
> 
> Just speculation, it looks like you increase the pressure - but not  much - and this increases the gas molecules per volume, and it leads to easier ignition.


Your correct about the resistance but, what is being seen is the ionization of the gases just like a neon sign. Compressing the air (gases) does increase the resistance in the gap. Most modern ignitions (automotive) start to fail @200 psi, a really good racing ignition (>$800US) is good to 400-500 psi, 4-5 bar boost and a small gap. NHRA & IHRA measure the dielectric resistance of fuel from your fuel tank after a run and if it is not within a given range your disqualified. One has to be very careful with alcohol because it sucks water out of the air lowering the resistance which, will get you disqualified. Also if you look at the insulators on overhead power lines you will notice they are disked or finned to use the air as a dielectric insulator which boosts the overall isolation.



mcostello said:


> Years ago I built a high voltage coil from a Radio Shack (remember them) kit. It did improve the idle quality. I happened to brush My hand across a plug wire while the engine was idling and woke up laying on the ground.


I got zapped by my old mega racing inductive ignition once when adjusting the timing. It went through my little finger and out my elbow. It sent me back about 6 feet and the timing light went flying about 20 feet. My forearm was numb for 2 hours.

Ray


----------



## 74Sprint

Gedeon Spilett said:


> relating to the Paschen law quoted above, I did a little test to see the spark while increasing air pressure with a syringe.
> and yes, the spark was much brighter upon pressure increase...
> but I don't have any way to measure these high voltage !
> 
> 
> 
> 
> 
> 
> 
> 
> New video by Francois-Marie Meunier
> 
> 
> 
> 
> 
> 
> 
> photos.app.goo.gl


I once found a setup and used it years ago. It used a series of high voltage zener diodes to test the high voltage output. The zeners were setup to cascade as the voltage went higher. Do a Google search for "high voltage zener cascade test setup" you should be able to find something to help you.

Cheers
Ray


----------



## bluejets

Dad had an old spark plug cleaner/tester in his workshop that cleaned the plugs via a sandblast.
After cleaning one would check plug gap and refit to the tester.
Air pressure was increased until the spark began to breakdown and reading taken.
Visual was via an internal mirror setup.


----------



## 74Sprint

A little more work on the calculations.
So now that I know the RPM what's next? Well I need to know how fast are the degrees flying by.

so (RPM x 360 degrees) / 60 = degrees per second.

Example: 300 x 360 = 108,000 per minute
                108,000 / 60 = 1,800 degrees per second

I know that my Hall sensor is 55 degrees before top dead center, so how long do I have before the crank goes from 55 degrees to TDC?

Time to TDC is 55 / 1,800 = 0.03056 seconds or 30.56 milli-seconds.

How much time is 1 degree? I can reduce this down to 1 degree by dividing the time by 55.
0.03056 / 55 =0.000556 seconds per degree or
1 / 1,800 = 0.000556 seconds per degree or 0.556 milli-sec or 556 micro-sec

so if I wanted say to have 10 degrees advance BTDC then I would tell the MCU to wait 45 degrees before firing and since the Arduino works with either milli or micro seconds, I'll use micro seconds because I plan to go higher RPMs:
45 x 556 usec = 25,020 usec. before sending out a coil fire trigger.

The 1 thing I haven't mentioned yet is the amount of time the MCU takes to calculate the RPM, do the table lookup from the EEROM to get the amount of timing advance at the calculated RPM, and send out the fire trigger pulse. I can setup a way in the code to time all this; trigger in, calc, lookup, and trigger out. Once I have this I then need to subtract that from the 55 degrees. So if the calculations take say 1 milli-second to do then my wait time would be 25,020 - 1,000 = a wait time of 24,020 usec before the fire trigger.

All this can seem a bit mysterious I know. I've had people with a degree in computer science that can't quite understand that the MCU can not forecast the future and needs time to do the calculation and WAIT to fire the coil. I think the confusion lies in the terms used such as advance the timing by telling the MCU to wait less time. But one has to remember that if you want to use an advance of say 20 BTDC then the Hall can not be set at 20 degrees BTDC because 20-20 = 0. The MCU will not have any time to do the calculations and will fire the coil at less than 20 degrees. This is because as the MCU is doing the calculations the crank is still turning toward TDC and time is burning up and the MCU will fire after the calculations are done, so no advance. This also brings us to "is the MCU fast enough to do the calculations at the RPM I want to use?" As for the Arduino Nano I don't know yet because I haven't finished my testing. I do have MCUs that are up to 200 times faster just incase the Nano can't handle 10,000 RPM on a single cylinder but, I think it can. I know it will not do 5,000 RPM on a 18 cylinder engine. This also brings us to "is there enough time to charge the coil 2-5 msec?" Might have to use more than 1 distributor and use 2 Nanos/MCUs or 2 distributors and 1 fast MCU. Mind you one can always use 18 LS1 coils and a fast MCU.

Cheers
Ray.


----------



## bluejets

I'd do the suck it and see approach.
Jam in something close, then check with a timing light.


----------



## awake

Your reasoning all makes sense to me. The nice thing is, you don't actually have to do any particular calculations in real time. Instead, calculate the values in advance for different RPM ranges, allowing for the time needed to process the ISR including lookup, set timer, etc. You don't even need to calculate RPM on the fly (unless you want to display it, but I would do that outside of any ISRs and just let it chug along) - instead, build your lookup table with the microsecond measurement of the pulse and the corresponding microsecond timer setting for the advance. Depending on the length of the table, you may to do the lookup via an indexing scheme of some sort (let the upper 3 bits of the pulse measurement give you the lookup table index, for example - scaled as needed, of course). Alternately, you may only need, say, 8 values for 8 RPM ranges, and it may be just as simple to walk through the table for the lookup - and build the time needed to get to the right lookup value into the corresponding timer setting. I would say that with a little finesse, you could arrange things in such a way that your ISR could complete in a very few microseconds, particularly if you set the table up so that lookups involving the highest RPMs always finish the fastest.


----------



## 74Sprint

awake said:


> Your reasoning all makes sense to me. The nice thing is, you don't actually have to do any particular calculations in real time. Instead, calculate the values in advance for different RPM ranges, allowing for the time needed to process the ISR including lookup, set timer, etc. You don't even need to calculate RPM on the fly (unless you want to display it, but I would do that outside of any ISRs and just let it chug along) - instead, build your lookup table with the microsecond measurement of the pulse and the corresponding microsecond timer setting for the advance. Depending on the length of the table, you may to do the lookup via an indexing scheme of some sort (let the upper 3 bits of the pulse measurement give you the lookup table index, for example - scaled as needed, of course). Alternately, you may only need, say, 8 values for 8 RPM ranges, and it may be just as simple to walk through the table for the lookup - and build the time needed to get to the right lookup value into the corresponding timer setting. I would say that with a little finesse, you could arrange things in such a way that your ISR could complete in a very few microseconds, particularly if you set the table up so that lookups involving the highest RPMs always finish the fastest.


Holly crap! how did you manage to read my code?   I'm not sure from what you're saying would give me 1 degree precision. I'm willing to try it if you can expand on your thinking. Actually using an index is how I get the EEPROM memory location to read. This is a lot faster than calculating the RPM and then either using a nested 'IF' statement. I also try to stay away from using division since computers can only ADD and division has multiple steps, it's the slowest of all the basic math operations. But when you have to, you have to. I also don't like to use interpolation because I think that is just a waste of time.

So indexing aka placing or looking up a value in an array by converting the range number into an index just as 1, 2, 3 etc. Let's say that I have a range for the advance values that goes up by 1,000 RPM, 0, 1,000, 2,000, 3,000 etc.
so:

(1/Time) x 60 = RPM between pulses or ((1/(T*0.327))/60)/100 = RPM pulse width

let's say RPM =4,655. Then 4655 should be in the 4,000-4,999 memory location. So a standard nested 'IF' statement would look like this.
IF RPM <1,000 then
    Look in memory location 1
else
    if RPM >= 1,000 and <2,000 then
    Look in memory location 2
else
    if  RPM >= 2,000 and < 3,000 then
    look in memory location3
else
    if RPM >=3,000 and <4,000 then
    Look in memory location 4
and so on....... end IF

Problem is that the MCU will read the whole condition.

A select statement would be faster because it just goes down the list until it finds a match, does what it is told and exits the select statement list.
Select RPM
    RPM <1,000
        look in memory location 1
    RPM <2,000
        look in memory location 2
    RPM <3,000
        mem_loc = 3
    RPM default
        mem_loc = 1
and so on..... end SELECT

I could also just get the first digit '4' but, if the RPM is 415 then the code will look in location 4 which is no good. I could also make my range step be 500 RPM which, would handle this but not 4,500. Even if I took the first 2 digits it wouldn't work because 04 = 4. There is also a other things I could do like checking the length of the RPM number and so on.

I could also do this:
Select RPM
    RPM <1,000
        IF RPM <1,000 and >500 then
            mem_loc = 2
        else
            mem_loc = 1
        end IF
    RPM <2,000
        mem_loc = 3

I have found with testing that looking up the value with the above code is in the nano-second range but, transferring that value to a variable is slow, it's in the micro-sec range or higher. Which is still plenty fast enough for my little 1 banger.

What is the fastest code? Well it is to make my range steps go up by 100 and just use the first 2 digits of the RPM.
So:
00, 01 to 09 converts to location 0, 1 to 9 and then 10 to 99 allows for up to 100 memory locations. The Nano EEPROM has 1024 locations. There is a problem with the ATmega328P MCU in that it needs time to transfer the lookup value from memory into a variable. This can be as much as 20 milli-seconds, way to long. I have had to use 20 msec only about 3 times to get stability. To do away with the wait(delay) it helps to store the values in Hexadecimal but, then you have to convert that value into decimal when reading the location value, no biggy. Doing this brings you back to nano-second times. As for a 100 RPM range I think that is to small unless one is using a hit-n-miss engine. I'm most likely going to use the code just like above with 500 RPM range steps.
So:
Select RPM
    RPM <500
        IF RPM <100 and >50 then  // Note engine is cranking, retard timing
            mem_loc = 1
        else
            mem_loc = 2  // Note engine is idling
        end IF
    RPM <1,000
        mem_loc = 3
    RPM <1,500
        mem_loc = 4
etc.....
    RPM default
        no_spark  //Note engine must be stopped
end SELECT
And so on something like this.....

Once I have the degrees of advance I just need to find the time per degree to get my holdoff time.

Now to make some code for testing.

Cheers
Ray


----------



## Steamchick

Fascinating discussion about coding/ programming. But way over my head.
But I did see a comment about the spark plug cleaner tphat sand-blasted the plugs. Post #200. My experience: I used one for my pocket full of plugs for my motorcycles in the 1960s.... I changed plugs every time I thought they  were not running right.... fouled, mis-firing or just losing power. Curiously, the sand-blasted plugs seemed to foul and lose power relatively quickly... A week, or tank of fuel, etc. (as opposed to just washed with petrol and something -  twig or cocktail stick - poked down the side on the insulator to clean...).
In a later life I worked with the Champion engineer selecting and testing appropriate plugs for the engines in our factory. He advised that the gloss finish of the plugs allows for the retention of less contaminant than the sand-blasted rougher finish I had experienced. What was happening to me was that the sand-blasted finish collected carbon in the pores/scratches, leading to flash-over down the insulator, especially during cold starting. This meant poor and delayed ignition, even mis-firing.
So I would not use plugs cleaned that way nowadays.
K2


----------



## DKGrimm

TonyM said:


> Slightly off topic. But can an ignition circuit be judged by the ability of a spark to jump a certain gap in air. So for example if a spark jumps 10mm in air is it likely to be OK under compression say 6 or 7 to 1



Here's a couple pages from a white paper I wrote (to myself) a while back.  It seems to give reliable results for inductive ignition systems and magnetos, although I have no idea how to use it with CDI.  This comes from a stash of similar working papers I have posted on www.dkgsite.com.


----------



## DKGrimm

Steamchick said:


> Fascinating discussion about coding/ programming. But way over my head.
> But I did see a comment about the spark plug cleaner tphat sand-blasted the plugs. Post #200. My experience: I used one for my pocket full of plugs for my motorcycles in the 1960s.... I changed plugs every time I thought they  were not running right.... fouled, mis-firing or just losing power. Curiously, the sand-blasted plugs seemed to foul and lose power relatively quickly... A week, or tank of fuel, etc. (as opposed to just washed with petrol and something -  twig or cocktail stick - poked down the side on the insulator to clean...).
> In a later life I worked with the Champion engineer selecting and testing appropriate plugs for the engines in our factory. He advised that the gloss finish of the plugs allows for the retention of less contaminant than the sand-blasted rougher finish I had experienced. What was happening to me was that the sand-blasted finish collected carbon in the pores/scratches, leading to flash-over down the insulator, especially during cold starting. This meant poor and delayed ignition, even mis-firing.
> So I would not use plugs cleaned that way nowadays.
> K2


Same as my experience with sandblasted plugs in my dad's garage when I worked there.


----------



## Steamchick

Hi Mr. Grimm. I also remember a spark plug tester for ignitions. The tester was a glass tube with a scale in 1/8" marks and the sharp-pointed earth contact could be moved away from the HV terminal (connected to the HT lead) to measure "sparking performance Voltage". The gap - around 1/2inch? - was deemed an "OK" ignition. But if if could not jump 1/4" then it was no good. (Not sure of the exact measurements, but there was a table of gap dimensions versus kV of the ignition! - 2kV being the "OK" point as I remember?). 
There was also a hand-wound magneto for testing the 18mm dismantlable-type spark plugs (Cleaning those was my job!). 
I believe both testers were "Lodge Spark Plug" company tools! - a Company absorbed by Champion in more recent years - (?). Ignition Technology has advanced a long way since then! Now I simply change plugs at 36,000miles, because it says so in the book, and I never worry about the car not starting for "dirty plugs", etc. The Champion rep advised that from the testing we conducted in the late 1980s/early 90s that the earliest failures would occur around double that mileage, just in case of a "missed" service. The Warranty was for 60,000 miles, so plugs needed to have sufficient platinum on the electrodes to withstand that mileage with fewer than 6 failures per million plugs). But AFTER MARKET plugs would only be good for 40,000 miles for 6ppm failure rate! - Less Platinum on the after-market electrode tips (Which should never have any abrasive cleaning applied - the platinum is only microns thick!).  - Don't quote me on that as aftermarket parts were not my remit, and my memory isn't perfect! That was the "Engineering" of lifetime of the serviceable parts! 
As I recall... the "fouling degradation" of the surface of the insulator was expected around the 70,000 miles (or more), providing "Good" clean fuel (Western economy countries) has been used. This is worse if the fuel is not "regular high quality lead free" (Some 3rd world nations). I also heard that NGK had the "best" clay in the world for this insulator application, which is one reason why they claim to be the "best" plugs...
Probably of no interest for models with home made plugs and ignitions and different performance parameters and fuels!
Enjoy,
K2.


----------



## awake

Ray, I am working up a rough sketch of what I was thinking, but in the process, I noticed what I think is problem with the units in your formula.

According to your earlier post, ((1/(T*0.327))/60)/100 = RPM where T = the pulse width from the hall-effect sensor, in *microseconds*. Unfortunately, this yields results that do not sound right: plug in RPM = 500 and it gives T = .0036670. If T is in microseconds, .003667 is a 3.667 *nanosecond* pulse! And its going to get even shorter at higher RPM!

I'm thinking T is actually in *seconds* in this formula. That would give a pulse width of 3.667 *milliseconds*. I checked that by calculating a single complete revolution at 500 RPM = 500 revolutions / 1 min = 8.333 revolutions / 1 second. Divide top and bottom by .8333 to get 1 revolution / .120000 seconds. So a single total revolution at 500 RPM takes 120 ms; a pulse-width of 3.667 ms would suggest that the hall-effect sensor pulses for about 11 degrees out of 360. That sounds about right to me.

Simplifying the formula (multiplying and dividing the constants) and solving for T gives me this formula: T = 1 / (RPM * .545). If you get a chance, see if that looks right to you.

Meanwhile, I will work up the sketch and will post it later today ...


----------



## awake

Okay, attached are two documents that try to sketch out what I had in mind. I started to put it all into a post, and it was going to be way too long, so I turned it into a .pdf file that describes the logic, and a spreadsheet that illustrates the calculations. Hopefully together these make sense, but if not, don't hesitate to ask. And on the flip side, hopefully this is not tediously telling you things you already know!


----------



## bluejets

Steamchick said:


> Fascinating discussion about coding/ programming. But way over my head.
> But I did see a comment about the spark plug cleaner tphat sand-blasted the plugs. Post #200. My experience: I used one for my pocket full of plugs for my motorcycles in the 1960s.... I changed plugs every time I thought they  were not running right.... fouled, mis-firing or just losing power. Curiously, the sand-blasted plugs seemed to foul and lose power relatively quickly... A week, or tank of fuel, etc. (as opposed to just washed with petrol and something -  twig or cocktail stick - poked down the side on the insulator to clean...).
> In a later life I worked with the Champion engineer selecting and testing appropriate plugs for the engines in our factory. He advised that the gloss finish of the plugs allows for the retention of less contaminant than the sand-blasted rougher finish I had experienced. What was happening to me was that the sand-blasted finish collected carbon in the pores/scratches, leading to flash-over down the insulator, especially during cold starting. This meant poor and delayed ignition, even mis-firing.
> So I would not use plugs cleaned that way nowadays.
> K2



Well, that was in the days of 36hp Holdens and the like, not exactly "race cars".
Why does everything with you blokes have to be performance related to the Nth degree, they are model engines for crying out loud.
Most are happy just at the fact that they will actually run.

Point was as the pressure increased the spark deteriorates.


----------



## Steamchick

Hi Bluejets: fair comment... However, this website has some contributors who are experts in their field, and some who just want to learn what makes "the best" into "the best". Whether it is machining precision, or engineering "best practice" - or anything else. 
I am happy with a 50% success rate on "runners", but still aim for "the best" - where I can learn and improve. (Murphy's 47th law: Aiming for the Bull's-eye means you'll have a better chance of hitting something! - or was it "Aiming for the Bull is good, speaking a load of Bull is not!").
Incidentally, I am curious just watching the discussion on something like this, as I am NOT making an ignition system, nor do I understand the computer coding discussion, etc., but within the discussion there are a few morsels of information that teach me something about bits I have fitted to cars - and not really understood what they do... 
 I would buy an ignition system and simply use it "from the box" - but that doesn't make this thread less interesting - to me at any rate.
On the technical side, I am curious to learn about ignition voltage and current and thought the success of ignition was down to "spark energy" - which is usually monitored by "open circuit voltage" of the HT side, as it is difficult to monitor the arc current (without high tech oscilloscopes, etc.). Hence, the input energy has a significant effect, which is part of the discussion above (points "dwell" on those old Holdens?). 
Aside: For 4 years I was an engineer designing HV switchgear - but never understood the stuff the HV Electrical engineer did to determine how to quench arcs of many hundreds of Amps at 500kV! - I just designed the equipment that managed to break the arcs, because I met his criteria for contact separation speed.... (distance and time = start-to-stop in 9 inches, in 0.05 seconds.). - Nothing at all like an ignition system...
Long live the freedom of speech where we are all equal, yet can maintain our different viewpoints without censure. (Except that  my wife is always right!).
K2


----------



## bluejets

Steamchick said:


> Except that my wife is always right!



That is the statment of the day and most important.


----------



## awake

Steamchick said:


> Incidentally, I am curious just watching the discussion on something like this, as I am NOT making an ignition system, nor do I understand the computer coding discussion, etc., but within the discussion there are a few morsels of information that teach me something about bits I have fitted to cars - and not really understood what they do...



Part of the reason I put the details into attachments rather than in a long post was to make it easier for folks to choose whether or not to dig into the messy bits!


----------



## DKGrimm

Steamchick said:


> On the technical side, I am curious to learn about ignition voltage and current and thought the success of ignition was down to "spark energy" - which is usually monitored by "open circuit voltage" of the HT side, as it is difficult to monitor the arc current (without high tech oscilloscopes, etc.). Hence, the input energy has a significant effect, which is part of the discussion above (points "dwell" on those old Holdens?).


I also have a EE background with a couple career years dealing with industrial electric power.  After retirement I spent more than ten years trying to teach myself about the energy, voltage, and current stuff you mention in ignitions systems.  I've collaborated with John Vietti to make some small magnetos that seem to work, including a construction series in "Model Engine Builder" for a magneto-igniter combination for a Red Wing (still running, BTW).  If you care to see some of my untutored musings on the subject, I posted working papers on www.dkgsite.com.  These have a bunch of math and engineering jargon, but some of that is necessary to really understand the innate complexity of ignition systems.  Albert Einstein is quoted as having said, "Everything should be as simple as possible, but not simpler".


----------



## 74Sprint

awake said:


> Ray, I am working up a rough sketch of what I was thinking, but in the process, I noticed what I think is problem with the units in your formula.
> 
> According to your earlier post, ((1/(T*0.327))/60)/100 = RPM where T = the pulse width from the hall-effect sensor, in *microseconds*. Unfortunately, this yields results that do not sound right: plug in RPM = 500 and it gives T = .0036670. If T is in microseconds, .003667 is a 3.667 *nanosecond* pulse! And its going to get even shorter at higher RPM!
> 
> I'm thinking T is actually in *seconds* in this formula. That would give a pulse width of 3.667 *milliseconds*. I checked that by calculating a single complete revolution at 500 RPM = 500 revolutions / 1 min = 8.333 revolutions / 1 second. Divide top and bottom by .8333 to get 1 revolution / .120000 seconds. So a single total revolution at 500 RPM takes 120 ms; a pulse-width of 3.667 ms would suggest that the hall-effect sensor pulses for about 11 degrees out of 360. That sounds about right to me.
> 
> Simplifying the formula (multiplying and dividing the constants) and solving for T gives me this formula: T = 1 / (RPM * .545). If you get a chance, see if that looks right to you.
> 
> Meanwhile, I will work up the sketch and will post it later today ...


You know I found that mistake yesterday morning and in the correct version time is in msec, also my correction factor changed to 0.325, (1/(Tmsec*0.325))*600 = RPM. How correct and accurate will be determined once it's all put together.
My table looks like this:

HzPulse WidthRPMTime msecRPM perCalculated RPM from PWDegrees55 degree Hall Time to1 Magnetmsec measuredfrom HzBetween Pulses measured1 second(1/(Tm*0.325)*600) = RPMper SecondTDC in seconds2.514.0000001500.23333333​131.8681791.208791​0.069513889​56.000000300176.0000000.10000000​307.69231846.153846​0.029791667​103.00000060090.4000000.05000000​615.38463692.307692​0.014895833​152.00000090062.8000000.03333333​923.07695538.461538​0.009930556​201.500000120056.8000000.02500000​1230.76927384.615385​0.007447917​251.200000150037.4000000.02000000​1538.46159230.769231​0.005958333​301.000000180030.8000000.01666667​1846.153811076.923077​0.004965278​350.880000210027.0000000.01466667​2097.902112587.412587​0.004369444​400.760000240023.4400000.01266667​2429.149814574.898785​0.003773611​450.680000270020.7600000.01133333​2714.932116289.592760​0.003376389​500.600000300018.7600000.01000000​3076.923118461.538462​0.002979167​550.560000330017.1600000.00933333​3296.703319780.219780​0.002780556​600.515000360015.6400000.00858333​3584.764721508.588499​0.002557118​650.475000390014.4400000.00791667​3886.639723319.838057​0.002358507​700.440000420013.4000000.00733333​4195.804225174.825175​0.002184722​750.400000450012.5200000.00666667​4615.384627692.307692​0.001986111​800.385000480011.8000000.00641667​4795.204828771.228771​0.001911632​850.360000510011.0000000.00600000​5128.205130769.230769​0.001787500​900.340000540010.4800000.00566667​5429.864332579.185520​0.001688194​950.32500057009.9200000.00541667​5680.473434082.840237​0.001613715​1000.30500060009.4200000.00508333​6052.963436317.780580​0.001514410​1500.20500090006.2200000.00341667​9005.628554033.771107​0.001017882​

It is hard to get accurate measurements with my sh*t DC motor controller, I'm more than likely am going to be tweaking the calcs. Your calculation T = 1 / (RPM * .545) pretty much jives with mine and looks good. Your hold-off time is also close to mine. I did more research into whether I should use an interrupt or just the Arduino pulseln (pulse length). If I use the pulseln then I can have it measure the pulse width in either milli or micro seconds using almost any pin I want without using up an interrupt. I can still call up an ISR to do my calculations without linking the ISR to anything and keep my speed up. Also the pulseln has a default timeout of 1 second if it sees no pulse. This would work good for me because I could take this as a stalled engine or one that has not started yet. Your theory discussed in your PDF would lean more toward time between pulses setup which, I may still have to do if PW doesn't work out. In my testing I first got the Hz of the rotating magnets, divided that by 2 and then converted that into RPM. But because the Nano won't know the RPM I used the PW to calculate the RPM and compared that to the measured RPM. Since I decided to use a SELECT function to get the memory location (0, 1, 2, etc) based on 100 RPM increments my PC computer program will use a 2D table that is seeded with some values already for the 100 location. What I want to do is allow a person to select a range and then enter the advance value just once and do this for each selected range. Most controllers use this setup today. There will also be 10 locations for the temperature timing adjust if required. If you look at the values below you'll see that 20 executions' is still less than 1ms. I don't think the calculations and lookup will be more than the 20 executions'. Note: serial communications are very slow and should be kept to a minimum and outside of ISRs.

I also did some timing of code and got this:
164681 cycles read all of EEPROM and transfer into RAM
RAM cycles per byte: 11.22
EEPROM cycles per byte: 40.23

clock cycle = 0.0625 micro-seconds at 16mhz
0.010293 seconds or 10.293 milli-sec to read all of EEPROM locations
RAM time per byte = 0.00000070125 seconds or 701.25 nano-sec
EEPROM time per byte = 0.00000251438 seconds or 2.51438 micro-sec

time to init board bare minimum = 8 micros
time to count to 10 and serial print each value = 884 micros

dwell time minimum = 2 milli-sec
This dwell time presents a problem with the Hall set at 55 degrees before TDC because I need 2 milli-seconds to charge the coil. With 2 msec. that means RPM is limited to <4,800 RPM unless I move the Hall to 90 degrees BTDC.

Well that was yesterday besides getting a heart monitor yesterday afternoon.

Cheers
Ray


----------



## awake

I've not used the pulseln function - I'll have to look into that one. Yes, absolutely agree on keeping serial communication out of ISRs, and if the main loop handles any sort of timing, out of that as well. I don't recall what sort of hardware serial buffering the Arduino / AVR may or may not have; if it does not have any significant buffering, I wouldn't want to use serial in the main loop even if the ISRs are handing timing in the background. As you say, serial is too busy and too slow, and yet can itself be time-dependent. Very convenient for reporting what is going on, also a great way to shoot yourself in the foot ... !



74Sprint said:


> clock cycle = 0.0625 nano-seconds at 16mhz



Just to be pendantic ... a 16MHz clock gives a .0625 *millisecond* cycle, which is to say, a 62.5 nanosecond cycle, or a .0000625 second cycle.


----------



## 74Sprint

bluejets said:


> Well, that was in the days of 36hp Holdens and the like, not exactly "race cars".
> Why does everything with you blokes have to be performance related to the Nth degree, they are model engines for crying out loud.
> Most are happy just at the fact that they will actually run.
> 
> Point was as the pressure increased the spark deteriorates.


Let's see I've worked on tractors, trucks, cars, and airplane engines from the 1930's and cars from the 1920's. I still like working on them when I get a chance and yes it is nice to see them just run. I really like going to the steam days where they have all the old stuff steam and petrol in working condition. But as for the Nth degree I am not sure, as for my race car I'd say it's more like 10th degree LOL. I love acceleration and with drag racing my reaction time and my tuning skills have to be near prefect to win. We're talking about races that I have won by 0.002 of a second combined. As for my other 2 cars I want to get the best gas mileage I can. As for my model engines, I want them to run and run reliably on 2 stroke fuel, nitro engine fuel is getting very expensive. As for this project it is a springboard to bigger things.

Cheers
Ray


----------



## 74Sprint

awake said:


> I've not used the pulseln function - I'll have to look into that one. Yes, absolutely agree on keeping serial communication out of ISRs, and if the main loop handles any sort of timing, out of that as well. I don't recall what sort of hardware serial buffering the Arduino / AVR may or may not have; if it does not have any significant buffering, I wouldn't want to use serial in the main loop even if the ISRs are handing timing in the background. As you say, serial is too busy and too slow, and yet can itself be time-dependent. Very convenient for reporting what is going on, also a great way to shoot yourself in the foot ... !
> 
> 
> 
> Just to be pendantic ... a 16MHz clock gives a .0625 *millisecond* cycle, which is to say, a 62.5 nanosecond cycle, or a .0000625 second cycle.


Right, I did it again typed it out wrong   Thanks again. There is pulseIn() and pulseInLong(). I believe the serial buffering is up to 2 bytes so not very good, it depends on how it is used, serial com or SPI. I have to rewrite some code for my coil winder because the serial com is not working out too well which, reminds me I have to call and find out where the hell my parts are at (lead screws).

Ray


----------



## 74Sprint

DKGrimm said:


> I also have a EE background with a couple career years dealing with industrial electric power.  After retirement I spent more than ten years trying to teach myself about the energy, voltage, and current stuff you mention in ignitions systems.  I've collaborated with John Vietti to make some small magnetos that seem to work, including a construction series in "Model Engine Builder" for a magneto-igniter combination for a Red Wing (still running, BTW).  If you care to see some of my untutored musings on the subject, I posted working papers on www.dkgsite.com.  These have a bunch of math and engineering jargon, but some of that is necessary to really understand the innate complexity of ignition systems.  Albert Einstein is quoted as having said, "Everything should be as simple as possible, but not simpler".


I've been to your website and I like it for the tid-bits and info. I worked for the railroad for 10 years and I still can remember seeing the flames come out of those arc-chutes on the switch gear and the bang that sounded like a gun going off in the cab. LOL

Ray


----------



## CFLBob

awake said:


> I've not used the pulseln function - I'll have to look into that one. Yes, absolutely agree on keeping serial communication out of ISRs, and if the main loop handles ...
> 
> 
> Just to be pendantic ... a 16MHz clock gives a .0625 *millisecond* cycle, which is to say, a 62.5 nanosecond cycle, or a .0000625 second cycle.



And to be a Pain In The A** more pedantic ,  a 16 MHz clock is .0625 *microsecond* cycle.  You correctly had that as 62.5 nanoseconds but then wrote the decimal as 62.5 *micro*seconds.   

The Rarely Stated Laws of the Universe includes one that covers this.   It's also included as a corollary of Murphy's Law.  

When correcting someone else's error, the chance of the corrector introducing their own mistake approaches 1.0.


----------



## awake

CFLBob said:


> And to be a Pain In The A** more pedantic ,  a 16 MHz clock is .0625 *microsecond* cycle.  You correctly had that as 62.5 nanoseconds but then wrote the decimal as 62.5 *micro*seconds.
> 
> The Rarely Stated Laws of the Universe includes one that covers this.   It's also included as a corollary of Murphy's Law.
> 
> When correcting someone else's error, the chance of the corrector introducing their own mistake approaches 1.0.


Where's the egg-on-my-face icon when I need it! Thanks, Bob. So that means that I was also wrong on .0000625 seconds - that one should be milliseconds instead. Sigh ... it's been a long, long time since I made a living bit-banging code and counting cycles, but I'm starting to remember one of the things on which I always had to check myself at least three times! Thank goodness I never had to do this with the multiple-gigahertz clocks of modern CPUs ... it would only be a matter of time before I substituted a femtosecond for a picosecond, and before you know it, I would have my code scheduled to complete before it started!


----------



## CFLBob

I rarely worked at frequencies that low as the input.  I designed two receivers that would cover 16 MHz, both for commercial aircraft.  Most of the time, I had handed the signals off to someone else by the time they were that slow.  I find working in "engineering notation" helped me the most.  That's scientific notation except with the exponents in multiples of 3.  16 MHz would usually be written as 16e6.  

I got chastised by a design reviewer from the JPL on a satellite we were doing for them, and instead of saying something like 16*10^6, I said 16e6.  "That's not 16 times e!  Correct your documentation!"


----------



## DKGrimm

74Sprint said:


> I've been to your website and I like it for the tid-bits and info. I worked for the railroad for 10 years and I still can remember seeing the flames come out of those arc-chutes on the switch gear and the bang that sounded like a gun going off in the cab. LOL
> 
> Ray


We once had a control circuit failure that closed a breaker connecting a stopped 1Mw synchronous alternator the the 12.5 kv line.  Started a fire and made the whole city of Dallas sag just a little bit.


----------



## Steamchick

Ray: re: post #220: Flame chutes on circuit breakers (with associated loud bangs!) were "before my time": I was designing 400kV SF6 gas breakers.... so the "bang" was inside the insulator containing 6~7 bar of SF6. A REALLY corrosive toxic gas, but excellent dielectric! So the only "Bang" that could be heard was when the valves operated and opened 6litres of air at 28barg from one side of the actuator piston, to atmosphere. The resulting differential pressure on the piston caused a very rapid acceleration (recorded 120g on the piston rod!). - It took about 4ms to operate the valves, and 0.1ms for the piston to start moving.... well that was the resolution of the "clockwork" paper recorders of the era. I also designed the silencers to bring the exhaust noise from the actuator exhaust down from 136dBA (previous design of silencer) at 1m to below 124dBA at 1m.  People in the village 1.5 miles away were very happy with the "new" breakers, that didn't sound loud... more like a small gunshot when the weather was in the right direction, not the echo-ey "Boom" of not-too-distant gunfire or quarry blasting from the air-blast circuit breakers!
Nowadays, the actuator is hydraulic, so the whole thing is much quieter. No exciting flashes and bangs either!
K2


----------



## 74Sprint

On locomotives they don't have anything that fancy, just switch gear for forward and reverse and power contactors for for power and dynamic braking. It's the power contactors that handled up to 1Kv and 1,200 amps each, 6 of them, one for each motor. If the power contactors opened somehow under full power/load then the arc usually got it's guts burned out of the arc chute, where that red label is. Opening under full load sounds more like an explosion and not a gun shot. They are not suppose to open until the generator field has decade. The contacts are made from pure silver about 3" long by 1"h x 1" thick.






On the RADARSs I worked on all the switching was done electronically into the megawatts range, that's all I can say.

ray


----------



## Steamchick

Thanks Ray. Interesting stuff (to me at least!). I do find though, that only people who have had hands-on experience of high power electrical stuff are interested in it. As a subject, Power station and smelter bus bars just "hum"! And (hopefully!) No-one ever knows circuit breakers are there, and do their job reliably!
Not subjects for general conversation!
So that's probably why I am such a boring old what's it to most people.
K2


----------



## 74Sprint

Steamchick said:


> Thanks Ray. Interesting stuff (to me at least!). I do find though, that only people who have had hands-on experience of high power electrical stuff are interested in it. As a subject, Power station and smelter bus bars just "hum"! And (hopefully!) No-one ever knows circuit breakers are there, and do their job reliably!
> Not subjects for general conversation!
> So that's probably why I am such a boring old what's it to most people.
> K2


I know when things get into high power & voltage things tend to get a bit weird.  
Anyway I did some more testing of code to see how long it takes to do the calculations of RPM, degrees to TDC, and to lookup a value stored in the EEPROM. It shows that all the calculations and lookup will take less than 1 usec see below. I didn't use the average stuff here. Also the total time will be less because I won't be printing everything out to the serial monitor or the LCD.

P_Time is the pulse width time I manually enter
R_EEPROM is the EEPROM read at location zero.
RPM is the calculated RPM
DPS is the Degrees per second calculated
T_TDC is the calculated Time to TDC

All times are in seconds.
P_Time 0.00120000
0.00039000
2564.10253906
R_EEPROM 32
RPM 1538.462
DPS 9230.769531
T_TDC 0.005958
1
148
147
0.669us

The Arduino code I used:
#include <EEPROM.h>
int before, after, timeSpent;
float average = 0;
float P_Time = 0.0012; //pulse time
float RPM = 0;
float DPS = 0; //Degrees per Second
float T_TDC = 0; //Time to TDC
float x;
float y;
int R_EEPROM; //Read Stored EEPROM location '0' and place it in here

void setup()
{
  Serial.begin(115200);
  TCCR1B = (1 << CS10); //Start Timer1 with /1 prescaler
  EEPROM.put(0, 0x20); //Store the value 32 in HEX (20) to location '0'
}

void loop() {
  float average = 0;
  { 
  TCNT1 = 0; //Clear Timer counter
    before = TCNT1; //Read timer value
    // Function to be tested
    //(1/(Tm*0.325)*600) = RPM original formula
    Serial.print("P_Time ");
    Serial.println(P_Time, 8); //Print pulse time to 8 decimal places
    x = (P_Time*0.325); //Had to break down the formula into sections to work
    y =(1/x);
    Serial.println(x, 8);
    Serial.println(y, 8);
    RPM = y * 0.6; //Couldn't use 600 for some reason, will look into it
    DPS = (RPM*360)/60; //Degrees per Second
    T_TDC = 55/DPS; //Time to TDC, Hall is at 55 degrees
    EEPROM.get(0, R_EEPROM); //Get the advance in degrees from the EEPROM
    Serial.print("R_EEPROM ");
    Serial.println(R_EEPROM);
    Serial.print("RPM ");
    Serial.println(RPM, 3);
    Serial.print("DPS ");
    Serial.println(DPS, 6);
    Serial.print("T_TDC ");
    Serial.println(T_TDC, 6);

  //Serial.println(x);
    after = TCNT1;
  timeSpent = after-before;

  Serial.println(before);
  Serial.println(after);
  Serial.println(timeSpent);

  average += timeSpent; 
  }

  average = (((average/10.0)-4.0)*62.5)/1000.0;//get average, substract the time it takes to manipulate TCNT1, multiply it by real time per timer tick and convert to us

  Serial.print(average,3); //Time it took to do all the above in the loop
  Serial.println("us");

  delay(5000);
}

I should have enough to actually come up with an overall code for the ignition.

Cheers
Ray


----------



## 74Sprint

Well I did some more work today as much as I can because of my surgery.
Anyway this is what I've done today. For starters I have disabled the temperature and LCD functions in my code for now and will add them back in later. I want to concentrate on the core of get a spark out which means I'm doing things in steps. I got the pulse width, RPM, hold-off time to TDC, and EEPROM lookup location done and working in code. Right now I'm using my little signal generator to send square pulses to interrupt '0'. Inside int0 the ISR function, I'm using the pulseIn() to get the pulse width in micro-seconds and so far the code is very close to the spreadsheet calculations. I'll have to verify it all later using my scope. The next step is to connect the Nano to the Hall circuit and get those working together.

What I did learn is using 55 degrees BTDC as a Hall setting is not going to work very well. At 55 degrees there is only enough time to have a dwell of 2 milli-seconds at a max RPM of 4200. If I move the Hall sensor to give me 90 degrees BTDC then the max RPM jumps up to 12,000 RPM which is something I thought would happen. Mind you this 12,000 RPM limit is for inductive or TCI ignitions (LS1&2 coils) but, as RPM goes up the amount of advance available goes down. If I were using my Sparky CDI then this goes up to 15,000 RPM. Also using 90 degrees allows for a max advance @40 degrees which is fine by me. The 2 biggest problems is the speed of the mcu and charging the coil. It's easy to use a faster mcu but the coil charging time is a lot harder to overcome. This is a good example of why on multiple cylinder engine manufacturers have gone to using distributorless with multiple coils even with constantly charging CDI's. 

I'm really happy that I could place the pulseIn() function inside the trigger interrupt routine because it saves a lot of coding/code. If I were using the time between pulses then I would use the ICP1 input capture. The nice thing about using the trigger interrupt is that when it happens the mcu puts everything else on hold like the temperature reading and the LCD update. Once the interrupt is done then the main code can run again normally and take the temperature reading and update the LCD until the next interrupt.

My majour concerns:
Storing the advance table in the EEPROM from my PC. I don't want to do what we did 10 years ago where we had to place the array in the code and reflash the mcu. We had made a Excel spreadsheet that allowed one to set their degrees advance to the RPM table. Once this was done you would click on a button and the spreadsheet would actually write the whole code for you to copy and paste into the Microchip IDE to reflash the mcu, PITA. I still have to write the program to do this as a one and done process and haven't figured that out yet, need time.

Tomorrow I'm going to hook the Nano up to the Hall circuit.

Cheers
Ray


----------



## awake

74Sprint said:


> I'm really happy that I could place the pulseIn() function inside the trigger interrupt routine because it saves a lot of coding/code. If I were using the time between pulses then I would use the ICP1 input capture. The nice thing about using the trigger interrupt is that when it happens the mcu puts everything else on hold like the temperature reading and the LCD update. Once the interrupt is done then the main code can run again normally and take the temperature reading and update the LCD until the next interrupt.


Hmm ... as best I can tell, and matching what you are saying above, pulseIn() blocks everything else while it waits for the pulse to complete. I'm not a fan of putting a blocking function inside an interrupt; not a problem if you genuinely have nothing else for the μcu to do, but if you want to report RPM or other information to an LCD, I would think you will have trouble with slow response. This is why I'd much rather keep all the time-critical code in short ISRs. But of course, the proof is in the pudding, and I will be happy to be proved wrong!



74Sprint said:


> My majour concerns:
> Storing the advance table in the EEPROM from my PC. I don't want to do what we did 10 years ago where we had to place the array in the code and reflash the mcu. We had made a Excel spreadsheet that allowed one to set their degrees advance to the RPM table. Once this was done you would click on a button and the spreadsheet would actually write the whole code for you to copy and paste into the Microchip IDE to reflash the mcu, PITA. I still have to write the program to do this as a one and done process and haven't figured that out yet, need time.


With apologies if I am "teaching grandma to suck eggs ..." there are a few approaches that I would consider. Depending on the size of the tables and available code space, I might build a default table as a *const* array. This will compile the table into the code space, but you can access it as a variable, e.g., to reset the EEPROM to default values. Alternately, if you can define the constants that let you calculate a default table, that code might be smaller than the tables - depending on the size of the tables. Finally, you could flash a program to set up your EEPROM with the default values, and then reflash just the code to your running program. If you had enough room in EEPROM, you might be able to store the default values there as well as the active tables. Just keep in mind that when it comes to actually running the program, you will want to access the tables from RAM - reading EEPROM is much slower.

Again, apologies if I am stating the obvious or telling you things you already know ... or worse yet, trying to make helpful suggestions while getting it all wrong!


----------



## 74Sprint

awake said:


> Hmm ... as best I can tell, and matching what you are saying above, pulseIn() blocks everything else while it waits for the pulse to complete. I'm not a fan of putting a blocking function inside an interrupt; not a problem if you genuinely have nothing else for the μcu to do, but if you want to report RPM or other information to an LCD, I would think you will have trouble with slow response. This is why I'd much rather keep all the time-critical code in short ISRs. But of course, the proof is in the pudding, and I will be happy to be proved wrong!


Point taken. Yes it will block in the ISR but, I can get away with using an interrupt with the pulseIn. Normally the pulseIn is just placed in the main loop and blocks there until the pulse is done so, it will still block the updating of the LCD. I don't plan on using the LCD as a primary tach it's more like a FYI thing. I believe getting the PW, RPM, and EEPROM reading is the most important. I did use your advice on using the RPM as an index for getting the EEPROM location, no searching is done., just 1 quick calc and straight to the location. "EP_Loc = (RPM/100)-1;" And 2 'if' statements for high and low ends. If I have to I will copy the array into RAM for more speed. The EEPROM can store 1024 entries but, right now I'm just using 115. Yup it's going to be interesting to see how all this is going to work together. From past experience it should work out ok.



awake said:


> With apologies if I am "teaching grandma to suck eggs ..." there are a few approaches that I would consider. Depending on the size of the tables and available code space, I might build a default table as a *const* array. This will compile the table into the code space, but you can access it as a variable, e.g., to reset the EEPROM to default values. Alternately, if you can define the constants that let you calculate a default table, that code might be smaller than the tables - depending on the size of the tables. Finally, you could flash a program to set up your EEPROM with the default values, and then reflash just the code to your running program. If you had enough room in EEPROM, you might be able to store the default values there as well as the active tables. Just keep in mind that when it comes to actually running the program, you will want to access the tables from RAM - reading EEPROM is much slower.
> 
> Again, apologies if I am stating the obvious or telling you things you already know ... or worse yet, trying to make helpful suggestions while getting it all wrong!


No apologies required, you are making informed suggestions and hey there is more than one way to skin a cat, I try not to have a closed mind. The way I have been doing the EEPROM and variables is by using a 'serial check' in my main loop and a Serial_Com routine. When it sees data coming in it parses out the data stream and updates everything. So "0-99" is my advance array(100) and "100-109" is for the temperature array(10) and "110-114" is for the other variables(5). Oh I have found out that if a store an 8 bit ASCII character it takes up 2 byte locations in the EEPROM whereas if I store HEX values it only takes up 1 location, nuts. In my old group ignition we had used 2 ignition advance curve arrays that could be switched back and forth while the engine is running and I might incorporate this feature in the future. If everything works out well today then I think I'll jump onto writing the PC software so I don't have to do the copy and paste from Excel.

I also plan on using the DS1822 which is an updated version of the DS18B20. It is in a TO92 package so it is small, sort of. I really like this temp sensor because it is a 1 wire device and it has self diagnostic functions. $9.00 CAD though.

Cheers
Ray


----------



## 74Sprint

Good news, bad news, good news.
The first good news; I hooked the Nano up to the Hall-Effect circuit and it works nicely no adjustments required other than 1 line of code. 

Bad news is that my trigger out pin had tons of jitter and I had very poor control of it. The trigger out pulses when set for 2ms ranged from 0.750 to 2.1ms and this sucked. I checked for noise, voltage problems, and even my interrupt routine, nothing worked but, it was very consistent in it's behavior. So I researched the Arduino site for answers. 

Second good news; one of the suggestions and there was many, was to use delayMicroseconds() instead of delay() for my dwell setting. Doing this made the trigger out pulse rock solid from 6 to 11,914 RPM. Note: because I'm using 2 magnets on my flywheel the RPM max is actually double of what I recorded and stated earlier so, real RPM limit is around 23,000 RPM, cool. This is because the time between input triggers would be double of what I recorded, yes .

Now that I had steady pulses except for the difference between the magnets which is about 13 RPM. I was able to do some more testing and this is what I found:
For a single magnet:
1.3ms dwell limits RPM to @23,000 RPM which is what my Sparky CDI needs to charge the cap and discharge through the coil.
2ms dwell limits RPM to @20,000 RPM
3.5ms dwell limits RPM to @12,000 RPM

Execution time:
The time for the following below is 1.1ms. Serial printing to the built in Arduino serial monitor which shows up on my PC screen.
pulsewidth 0.165000
0.05362500
18.64801979
RPM 11188
DPS 67128
T_TDC in seconds 0.00134072
EP_Loc 99
Advance 0

With no serial printing the execution time is:
220usec.

Now Andy (awake) is correct in stating that using the pulseIn() and the delayMicroseconds() is frowned upon when used inside a interrupt routine because they both do what is known as blocking. When one uses a blocking function everything is put on hold until the function is finished. This is also what a ISR interrupt routine does so, it's basically putting an ISR inside a ISR which, kind of negates the purpose of an ISR. ISR's are supposed to be used when something important is "time critical". In other words use very small code and get out of it. But sometimes one has no choice or the benefits out weigh the negatives. But as I said previously mechanical things when compared to electronics, the mechanical is very slow. In my case here, my theory worked out.

Now that I have the Hall_effect pulse going to the mcu and I have the RPM, degrees per second, and the time to TDC calculations done the next thing to do is calculate the hold-off time to get the proper timing advance. Ok more math. Problem is that as RPM goes up the degrees per second goes up so the amount of hold-off time changes and the degrees of advance goes up, usually. But there is a relationship going on here. so the first thing to do is find out how long does 1 degree take. Also since I now know that the Nano works better with micro-seconds, I want to bring the hold-off time down to micro-seconds. First we need the DPS (degrees per second) which I got from the RPM. Next I need to know how long 1 degree takes: (Time per 1 degree = 1/DPS). 
Example:
RPM = 3600
Revs Per Second = 3600 / 60 = 60 RPS
DPS = 60 x 360 = 21,600 degrees per second

Next I need to know how long in seconds does 1 degree take at 3,600 RPM.
Time for 1 degree in seconds = 1 / 21,600 = 0.0000462963 seconds per degree

Next I need to know how much time do I have to TDC from 90 degrees (Hall-Effect), this changes with RPM
Time to TDC in seconds = 90/DPS or 90/21,600 = 0.0041667sec or 4,166.7 usec

So now let's say I want 10 degrees advance timing at 3,600 RPM. Got the 10 degrees that was programmed into the EEPROM.
The time before TDC for 10 degrees at 3,600 RPM is:
10 x 0.0000462963 seconds per degree = 0.000462963 seconds Before TDC. or 462.962 micro-seconds at 3,600 RPM.

Now to get there I need to know how long it takes to go from getting the Hall pulse length to the end of calculations before I start my Hold-off time. Right now I'm just going to use 220 usec.

Time to TDC in usec = 4,166.7
 4,166.7 - 220 = 3,946.7 usec is my Time to TDC now. Got the pulse, measured it and did the calculations needed so what's my Hold-off time now?

I have to to subtract the time before TDC for 10 degrees.
3,946.7 usec - 462.962 usec = 3,483.73 usec hold-off time. But since I want to use 2 msec dwell I have to account for that, so 2 msec = 2,000 usec.
3,484 -2,000 = 1,484 usec Hold-off time using a LS1/2 coil. On a CDI ignition there is no real dwell time so the firing time is at the end of the Hold-off time. The dwell part of it starts at the end of the spark on a CDI.

So at the end of the Hold-off time I turn the trigger output on for 2 msec (dwell time) and then turn it off. The LS1/2 coil will fire when they see a negative going pulse.

I know it's a long post and there is lots of math. I'm sure most people who have read this, if they read all of it are saying 'Ray who gives a sh*t, all I want is to see is 10 degrees of advance when I say I want it'. Well I'm getting there and besides as I said at the start of this thread "I want to show people what it takes to make things happen". When I start to make the PC software I won't be doing these long posts. Using Visual Studio to write a PC program is very advanced for this forum but, I'll show some pictures and ask for input on it's design from people on here. 

Next up:
Turn the stuff up above into code, test it, fix it, and then hook up an LS coil to make sparks, I'll make a movie when I get there with a little LED timing light. For the connection between the coil and the Nano I will be using a 2N7000 FET, I love these little buggers.

Cheers
Ray


----------



## Peter Twissell

Excellent work, Ray!
I have some half baked code to run the ignition for my radial, using an ESP32 PIC.
It will be interesting to see whether my PIC shares the foibles of your Arduino.


----------



## 74Sprint

Thank you Peter.
Question?
ESP32 or DSP-PIC32

Ray


----------



## Peter Twissell

I have an ESP32, but so far I've been playing with code on a PIC18 dev kit just for practise with no consideration of execution speed.
I should add that I am very much an amateur programmer, but we seem to have arrived at the same mathematical solution.
I have wondered whether to keep the advance value in time (rather than converting to angle) as it seems intuitively that what the engine needs is a time advance, to allow for flame front speed.


----------



## 74Sprint

Well I did more testing yesterday and this morning. Didn't get as much done as I had wished but, that's the way it goes sometimes.
First of all, I bought myself a new digital scope to replace my old Phillips one some months ago. It's a Rigol DS1054 4 channel with all the updates including unlocked firmware and now does 100mhz. This thing is miles ahead of what I was used to and has more bells and whistles than I really need but. what the heck gotta treat yourself sometime. Still trying to learn this thing.

So I added the code for the Hold-off time and moved the serial printing to the void loop() and guess what no 'loop' coming out of the interrupt routine. I found the problem and it's related to the pulseIn() blocking function. To get around this I had to add a call to the void loop() routine. Does the trig-in interrupt still work? yes it does. Printing to the serial monitor is interrupted during the interrupt. The serial print will be replaced with the LCD updating later but, the update will not be steady because of the ISR routine. To do this properly I would either need to use another Nano or an external tach, just to let you'se know. Also it updates faster at higher RPM because of having to use a call to the 'loop' routine but, I'm happy with it.

It is really nice to see the Hold-off working properly and matching the calculations. But we'll have to see how well it works on an actual engine. Which got me thinking: how much timing advance can this thing handle? and how will someone without a scope going to set the timing up correctly?

I tested the max timing with the Hall set at both 90 & 60 degrees. In both cases the max timing has to be 5 degrees less than what the Hall is set at. So if you have a Hall fixed at 90 degrees then the max would be 85 degrees advanced timing and likewise for 60 it would be 55 degrees. More than enough to blow an engine up.

Because not everyone is going to be using the same magnet, Hall-Effect, and the distance between them that I use, there has to be a way to help them. What I thought up was, one would enter in the degrees that the Hall turns the Trig_In LED on when you turn the crank by hand. Then they would set timing to 0' degrees advance. You would then start the engine and play with the processing time setting until you get a showing of 0' degrees on the crank with a timing light. Mind you one could also use something like 10' degrees advance. To do this no other advance can be used while setting this up, so a locked in setting.

Also I found that the minimum RPM reading is 60 and I believe that's because of the math involved. Anyway, next I want to clean out the EEPROM and load in an advance curve to make sure that part is working then attach an LS2 coil.

Cheers
Ray


----------



## 74Sprint

Peter Twissell said:


> I have an ESP32, but so far I've been playing with code on a PIC18 dev kit just for practise with no consideration of execution speed.
> I should add that I am very much an amateur programmer, but we seem to have arrived at the same mathematical solution.
> I have wondered whether to keep the advance value in time (rather than converting to angle) as it seems intuitively that what the engine needs is a time advance, to allow for flame front speed.


That's what I was going to use (ESP32) as a backup mcu incase the Nano didn't/doesn't work out. The code I'm using and because Arduino works with both our processors my code should workout for both.

Ray


----------



## propclock

Silicon Chip magazine did a programable ignition 3 issue series on this 
subject. They used a 16f88 I believe. They sell the complete assembly code  for 3$
I played with it and it works.  Generating the timing code table is a bit tedious. 





__





						Programmable Ignition System For Cars; Pt.1 - March 2007 - Silicon Chip Online
					

Want to program your own ignition timing maps for an older car or for the racetrack? Now you can with our latest programmable car ignition system. by John Clarke




					www.siliconchip.com.au


----------



## 74Sprint

propclock said:


> Silicon Chip magazine did a programable ignition 3 issue series on this
> subject. They used a 16f88 I believe. They sell the complete assembly code  for 3$
> I played with it and it works.  Generating the timing code table is a bit tedious.
> 
> 
> 
> 
> 
> __
> 
> 
> 
> 
> 
> Programmable Ignition System For Cars; Pt.1 - March 2007 - Silicon Chip Online
> 
> 
> Want to program your own ignition timing maps for an older car or for the racetrack? Now you can with our latest programmable car ignition system. by John Clarke
> 
> 
> 
> 
> www.siliconchip.com.au


I have been working with electronic ignitions since 1975 and programmable ignitions since 1996. I have seen many different types from ones using the intel 386 to dedicated processors of today (ASICs). All the ones that I have seen or read about need at least 2 pulses to sync the angular velocity to ignition timing, never doing this with just one pulse. Also they were all a PITA to program the ignition curve unless one bought PC software from @ $100 and up and that's even if there was an offering. There has been an explosion in programmable ignitions ever since mcu/mpu manufacturers started offering their IDE or development software for free. Then again there are dev software like the Arduino that have simplified things a lot and brought coding to the masses. There are so many ways to do things today that it becomes hard to decide which way to go. Do I go for cost, speed, features, or a combination of them. My main concern is to make it cheap enough that anyone can build one and provide PC software that allows one to make an ignition curve easily. This is just my flavour of the day.

Ray


----------



## 74Sprint

The ignition curve: Ignition advance movie




Have you ever had one of those days when you have a brain fart and spend hours doing something only to realize the answer was staring you in the face? Of course you have, your a hobbyist. Well I had one and it related to the EEPROM. To check out the writing and reading of the EEPROM I created an ignition curve in Excel and saved it as a *.csv (comma separated values) file and using notepad I copied and pasted it into my code. During the setup routine I had the values programmed into the EEPROM from locations 0-99 for 100 values.

0,0,0,5,5,5,5,5,5,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40

Each one is a step of 100 RPM up to and including 10,000 RPM. Remember I was saying that the EEPROM stores values in HEX as 1 byte and everything else is 2 bytes? The problem with this is that the locations would not go up 1 at a time, it is more like 2 at a time. This is because unless you tell the firmware that you are using 8 bit bytes it treats the bytes as 16 bit taking up 2 locations. This creates 2 problems; one you use twice as many locations than you need and second you have to compensate in the code by jumping 2 locations for every read of the EEPROM. So if you want to store a single 8 bit byte then you have to use the 'uint8_t' as compared to the 'uint16_t' and I forgot this. Also I could not find anywhere that would explain this behavior properly. According to the datasheets the 328 mcu uses a 9 bit byte to allow for signed (+-) values. So if one doesn't say 'uint8_t' (unsigned integer) then it adds in a signed value and spills over into the next location. Also the 328mcu doesn't write 1 location at a time but, instead writes a whole page at a time, just some FYI.

Anyway does timing advance work, yes it does. On the scope I can see the input trigger pulse width get smaller, the output trigger stays the same 2 msec dwell, but, the distance between the input trigger and the output trigger changes with the RPM and the programmed advance timing. As the RPM goes up and the advance increases you can see the sudden decrease in distance. Less distance between them means more advance in the timing, less Hold-off time.

I made a video of the scope and computer screens to show the advance working away. The values I used were:

0,0,0,0,0,0,0,0,0,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40

no advance from 0-800, 20 degrees from 900-3,300, and 40 degrees 3,400-10,000 RPM. Actually in the video I hit @11,300 RPM. Sorry about the shaking and poor audio. Ok I think I'm ready for the ignition coil now, I think.

Cheers
Ray


----------



## 74Sprint

Making Sparks: Making Nano Sparks movie





Finally I'm making sparks and 1 thing is for certain my jury-rigged timing light sucks, I'll make a better one. I made a slow -mo movie but, it kind of sucks also and had to use my editing software to look at it frame by frame. It showed that on one magnet I'm off by about 3 degrees and the other is off by 5. I can get rid of this by adjusting the Hall's location in software and of course if I had only 1 magnet it would be easier. In the movie the sparks quits every now and then but, it only did it in the movie, go figure. Otherwise it was steady as a rock. Also using a longer dwell gave a better spark and it was nice to see that using a 4msec dwell I could get up to 11,000 RPM but, it starts to cut out @11,500 RPM. There is a noticeable harmonic with the LS2 coil @6,500 RPM where the spark dies down a little but, that's 1,000 RPM higher than the old GM-HEI 4 wire and not as bad. I don't know the spark strength yet, I'll wait until I have a safer setup for that. One thing I'm really happy about is the noise from the coil. It's only about 8 volts negative and about 11 volts positive so, this shouldn't be to hard to cleanup. Something strange, when I turn the motor off and let it stop it will keep firing at a rate of a heart beat. This stops if I push the reset button on the Nano. This only shows up when the motor is not turning, something else to fix.

So it seems that I have all the core hardware prototyped and I can start on the PC software for programming the Nano. I have a board designed already and will order them most likely at the end of next month. I'm using an Infineon IPP25N06S3L-22 OptiMOS-T2 Power-Transistor to drive the coil trigger signal, it stays cooler than the Nano. And of course like a lot of my stuff it's obsolete, I'll have to find a newer alternate. Maybe I should have just went with the 2N7000 FETs like I was going to do, I will in fact. I'm going to be using this setup as basis for another ignition for my race car which will be a distributorless ignition for my Olds 455. Well the cam sync is actually a Ford Mustang (5.0L) cam pulser that also drives the oil pump.

So I'm vary pleased with the way things have worked out so far. More on the video, the actual sparks at idle @550 RPM looked both blueish and orange to me but, on the video they were just orangish in colour, blue filter on my phone. Also I apologize for the spark cutting out, I kept hitting some wires that made the spark cutout. The Nano and LEDS only drew 30ma which was nice, not sure what the coil drew, I'll check later. So I have some filtering to do like pull-ups or pull-downs on unused pins an such, also maybe a snubber circuit, we'll see.

Cheers
Ray


----------



## CFLBob

74Sprint said:


> In the movie the sparks quits every now and then but, it only did it in the movie, go figure.



I may be in quite over my head here but I would expect the spark to be missed by a movie at seemingly random intervals, unless the camera shutter is somehow synchronized to the engine.  Digital cameras make it more confusing to explain, but they still have an amount of time the shutter is open and the light collected, followed by an amount of time with the shutter closed to read the sensor contents into memory.  If they're not synchronized to, say, open the shutter a few milliseconds before the spark (or more after the previous spark), I'd think the fact they're running on different time bases would have you miss the spark sometimes.  You'd have to be especially lucky to catch every spark.


----------



## 74Sprint

CFLBob said:


> I may be in quite over my head here but I would expect the spark to be missed by a movie at seemingly random intervals, unless the camera shutter is somehow synchronized to the engine.  Digital cameras make it more confusing to explain, but they still have an amount of time the shutter is open and the light collected, followed by an amount of time with the shutter closed to read the sensor contents into memory.  If they're not synchronized to, say, open the shutter a few milliseconds before the spark (or more after the previous spark), I'd think the fact they're running on different time bases would have you miss the spark sometimes.  You'd have to be especially lucky to catch every spark.


Sorry about the confusion of what I wrote but, what I meant was a 'Murphy's law' thing because, I did several runs and didn't have the spark quit. But when I made the movie I was trying to hold the phone and watch what I was recoding. I have a bad connection on the trigger going to the coil and if I hit or touch that wire it sometimes looses it's connection.

I'm into digital photography and understand what you mean about the camera not catching all the sparks. I reviewed the recording and yes I agree with you. It shows up around the same time or speed of the frames per second the camera has. I know from watching with my eyes there was sparks but the video shows sparks dropped. I know there is no mechanical shutter but the processor reads the sensor line by line and I know this can also cause artifacts to appear or missed. My phone has a frame rate of 28 fps so anything around that or a harmonic of that will cause some problems. Oh well. I should have used my little movie camera it's like a GoPro that has a frame rate of 300 fps and made a movie, maybe next time that's what I'll use.

Cheers 
Ray


----------



## 74Sprint

I forgot to mention, on the scope at very high RPM it looks like it is firing on every other pulse but, it's not really, this is just the scopes triggering off channel1. If I just use channel 2 the output trigger then everything is fine. I'm still trying to learn all the features of this scope. I find that if I take the RPM very slowly then the scope will stay in sync and show all pulses to 11,000 rpm.

Also the LS2 coil will work with a dwell done to 0.5msec but spark is quite weak. I've tried from 0.5 to 4.0msec and find that 2.5-3.5 is best for spark and RPM.

Ray


----------



## awake

74Sprint said:


> Something strange, when I turn the motor off and let it stop it will keep firing at a rate of a heart beat. This stops if I push the reset button on the Nano. This only shows up when the motor is not turning, something else to fix.


My first guess would be that a timer is counting down to zero, firing an interrupt, and looping back through to do it all again.


----------



## 74Sprint

awake said:


> My first guess would be that a timer is counting down to zero, firing an interrupt, and looping back through to do it all again.


Andy I checked and the interrupt is firing that's for sure, not exactly sure why but.... On the scope it shows that there is an ignition noise pulse showing up on the output of the 2N4403 which feeds to the int0 on pin 2 which should fire the interrupt. I believe this is where I'll start to track this down. Most likely I need some decoupling caps, which doesn't surprise me. It's fine when the mcu is first turned on or reset. I'll check it tomorrow and report back.

Cheers
Ray


----------



## 74Sprint

Ok time for some really bad news. My normal supplier here in Canada sent me an email saying that the 328p processor which is what the Uno, Nano, and others use is either drying up or is no longer available on the market. He only has what he has in stock until next year!!!! So I went to the Microchip website and sure enough, this is what Microchip has posted for availability for All of the 328p packages;

"Out of Stock
Order now, can ship on 29-May-2023"
These normally price out from their website at $2.49 USD.

But if one wants to buy the automotive grade ones;
"Out of Stock
Additional quantities can ship by 26-Sep-2022"
These normally price out from their website at $5.25 USD.

So I'm not sure which way I'm going to go here. Might have to use a different micro-controller that stay's with the Arduino development environment.

Ray


----------



## awake

74Sprint said:


> Andy I checked and the interrupt is firing that's for sure, not exactly sure why but.... On the scope it shows that there is an ignition noise pulse showing up on the output of the 2N4403 which feeds to the int0 on pin 2 which should fire the interrupt. I believe this is where I'll start to track this down. Most likely I need some decoupling caps, which doesn't surprise me. It's fine when the mcu is first turned on or reset. I'll check it tomorrow and report back.
> 
> Cheers
> Ray


Ah, noise on the interrupt line. Hmm - you said about heartbeat rate; could it be picking up some 60Hz noise from the mains?


----------



## 74Sprint

awake said:


> Ah, noise on the interrupt line. Hmm - you said about heartbeat rate; could it be picking up some 60Hz noise from the mains?


Nope I checked for that and I can induce 60 Hz. hum with my hand if I want to. As soon as I take the scope probe off it stops. I moved the scope leads away from the high tension wire and it's better. Only sparks 2-3 times and stops. I need a little more work on it yet. Maybe a filtering inductor would help, something to play with.   Oh, the spark is strong enough too burn through a sticky label, cool.

Cheers
Ray


----------



## 74Sprint

Well it was bound to happen. My degree wheel came off the motor yesterday at about 11k-12k rpm. Needless to say I'm going to have to come up with something better or stop at 6,000 rpm. The saga continues. 

Ray


----------



## stevehuckss396

Tell me you have video!!!!


----------



## awake

74Sprint said:


> Nope I checked for that and I can induce 60 Hz. hum with my hand if I want to. As soon as I take the scope probe off it stops. I moved the scope leads away from the high tension wire and it's better. Only sparks 2-3 times and stops. I need a little more work on it yet. Maybe a filtering inductor would help, something to play with.   Oh, the spark is strong enough too burn through a sticky label, cool.
> 
> Cheers
> Ray


Well, rats. I always hope it's going to be something simple. But hey, complications keep life interesting, right?


----------



## dsage

74Sprint said:


> Well it was bound to happen. My degree wheel came off the motor yesterday at about 11k-12k rpm. Needless to say I'm going to have to come up with something better or stop at 6,000 rpm. The saga continues.
> 
> Ray


Use a function generator (or even a simple 555) and eliminate the physical wheel/hall/magnet/ motor etc. all together. That will also allow you to adjust the pulse width and rpm and will be more accurate and stable.
Also no need for your "timing light". You have a scope - use it to measure everything.


----------



## 74Sprint

stevehuckss396 said:


> Tell me you have video!!!!


No I don't, sorry. I'm going to have setup my little GoPro and start recording everything just encase. 
When it flew off it took out the Hall-Effect, broke the motor loose, and then hit me square in the chest. It then went to my right and landed in a box with a plastic bag in it, spinning away. When it started to slow down it climbed out and raced across the floor. I have no idea where the 2 magnets went but, 1 of them took a chunk of the disc with it. My daughter said to me "dad did you remember to roughen up the surface before epoxying them on?" I said " hell no, I'm 60 years old, do you want me to remember everything"  That's a lot of force/weight spinning around at 12,000 rpm.



dsage said:


> Use a function generator (or even a simple 555) and eliminate the physical wheel/hall/magnet/ motor etc. all together. That will also allow you to adjust the pulse width and rpm and will be more accurate and stable.
> Also no need for your "timing light". You have a scope - use it to measure everything.


That's exactly what I was thinking 2 555's or a 556 should do it. I wanted to simulate a real flywheel and I think I have done that so it's best I do it a smarter and safer way. LOL, funny you should mention that Dave because that's what I was trying to do and do a recording on the scope. I haven't checked yet if there is a recording in the scope storage. If I have it I'll post it. I wanted to use a timing light because most people don't have a scope, oh well.

Cheers guys
Ray


----------



## 74Sprint

Just wanted to say that I'm still working on this ignition. Just that I've been busy with other stuff and working on the computer program for setting the advance tables. Once done it will be just a matter of clicking on the upload button. I've tried a few languages that I think will allow me to adjust the values by multiple selections and communicate by serial with the mcu. Like electronics and machining there is more than 1 way to skin a cat, it's just deciding which way to go that's troublesome..

Ray


----------



## 74Sprint

Opinion Poll: Feedback needed.
There is an inherent problem between programmers and users. Programmers have there idea of how things should be and users have theirs, so here's your chance at giving me some feedback.

The screenshot below is of the table you could say that allows one to set the timing versus the RPM. I like the colours   but I can go 1 of 2 ways to increment the timing values. To begin one would select the cells either by 1 at a time or drag the cursor over the cells you want to change, they will turn blue in colour. next you would click on one of the controls to change the selected cells values up or down. Now I need to know which controls people would like to use Either option 1 or option 2 controls but, not both. After you change the values one clicks on"apply" and then "save". Oh I forgot to add a "reset values button" in case you change your mind.






Remember this is a work in progress and features will be added and/or removed as time goes on and by popular demand if possible. The first cell shows RPM from 0 to 100, next is 100 to 200, and the last cell is 900 to 1000 in that row. The very last cell in row 10 is 9900 to 10,000 and I think that's lots for now. I may or may not add a graph of the curve but, for now this will have to do. Every computer programming language has things that it either allows you to do or it doesn't. Because I'm using Visual Studio, actually VB.NET I'm already at 2,000 lines of code, talk about bloatware. Anyway option 2 is easier for me (less code) but, I understand my program but, you people have input here. My ego is not too big so that I can't take constructive criticism So Have At It, let me know what your thoughts are. Option 1 or Option 2.

Cheers
Ray


----------



## stevehuckss396

Have an input box that the number can be set in. Then when you double click where the value goes in the chart that number changes to the number in the input box. Then you can quickly set the entire table.


----------



## stevehuckss396

Also the table needs to go higher unless your ignitions are for single cylinders or v8s that only run at 2500 rpm


----------



## 74Sprint

stevehuckss396 said:


> Have an input box that the number can be set in. Then when you double click where the value goes in the chart that number changes to the number in the input box. Then you can quickly set the entire table.


I could do that but, I would have to use a textbox. I would have to do a check to make sure the number can be converted into an integer. If it fails I would then need to tell the user of the mistake. For example "3.5" would fail because of the period also "1O" would fail because that's an 'O' instead of a '0'. You could also just select the cell you want to change and type in the number. You could also select all the rows by clicking on each arrow at the start of the row which, would select the whole row. Hum I'll think about that one Steve and get back to you.

Ray


----------



## 74Sprint

stevehuckss396 said:


> Also the table needs to go higher unless your ignitions are for single cylinders or v8s that only run at 2500 rpm


The program doesn't know how many cylinders there are, it's the ignition circuit itself that limits the number of cylinders and RPM. Right now using the LS2 coil and my degree wheel with 2 magnets (2 pulses per rotation) the spark starts to weaken @11,500 RPM and gives up the ghost @15,000 RPM for a 4 cylinder 2 stroke using wasted spark, not enough dwell time. a V8 using a distributor running off the cam (half speed) the RPM limit of the coil should be the same RPM. Using my degree wheel it got 12,500 RPM which, would work for a 4 cylinder 4 stroke using a crank trigger. A V8 with a cam dizzy would be the same RPM. If I use my CDI coil and CDI ignition then that number goes up to 25,500 V8 4 stroke RPM with a distributor running off the cam. With a 2 stroke (1 or 2 cylinders) that goes up to 51,000 RPM. For now I'm going to leave the program at 10,000 RPM, once finished I can always increase the max RPM. I think I got my RPM vs cylinders vs # of strokes correct.   

Ray


----------



## stevehuckss396

Right on man. Keep on trucking!


----------



## bluejets

Well intended Ray but if memory serves me correct, others have gone down this path where input is rampant and every second one wants something different. Result is it never gets completed.


----------



## Stefan-K

Hi Ray
I would prefer Option 2.Checking All the boxes by dragging the cursor over them and change them all with one click. 
In real life one will Not change These numbers too often. So it should be done quick and easy. 
Good work! Keep on.


----------



## 74Sprint

bluejets said:


> Well intended Ray but if memory serves me correct, others have gone down this path where input is rampant and every second one wants something different. Result is it never gets completed.


I hear what your saying. I remember 2012 and all the different ideas but, I did not start that project. I also remember what Grompy said so, I will not let that happen here. I have learned from other projects I have done that sometimes you have to force people to accept and learn to use what they have been given. I learned there is always a time when a projects mandate has to be enforced and not accept more changes and have them sign off on it otherwise, your right it never gets completed. 

There is another problem on the horizon and that has to deal with the shortage of the Atmega328P mcu. Because the cheap version won't be available for a year I will be asking for feedback on using an alternative mcu. Which one most people will feel comfortable using. I'm pretty sure I will use something like the ESP32 or RP2040 that is compatible with the Arduino IDE for programming. They are cheap, powerful, and available ......... overkill for this project.

Cheers
Ray


----------



## 74Sprint

Stefan-K said:


> Hi Ray
> I would prefer Option 2.Checking All the boxes by dragging the cursor over them and change them all with one click.
> In real life one will Not change These numbers too often. So it should be done quick and easy.
> Good work! Keep on.


Thanks.
I have some corrections to do like remove the pre selected cells. I also think I'll do something like Steve asked for by adding a textbox that shows the value one wants to place in the selected cells to remove any confusion and makes it easier to read. Also the "timing.csv" file will have some preloaded values to populate the cells.

How this works, is that when one selects save, it's the "timing.csv" file that gets updated. It is also the file that gets uploaded to the Nano mcu's EEPROM for timing advance.

Cheers
Ray


----------



## 74Sprint

There is an old saying in computer programming "anything Microsoft makes, someone else also makes and makes it better". Now I use Microsoft's Visual Studio to write my programs. Why? well for 1 it's free and 2 that's what most others are using for general purpose programs and more. I started off using C# but, I couldn't get it to do what I wanted so, I switched to VB.NET. But that was so flakey that it was adding code that was wrong, losing my code, and becoming too difficult to use so, I switched back to C# and upgraded to Visual Studio 2022. VS 2022 works better in some ways but MS took out some features and added some. But in Microsoft's infinite wisdom and habit they do a real shitty job at documenting their stuff and a lot of stuff is hidden. Which means I have to search the internet for the info a lot. I like C# because it is somewhere between Visual Basic and C++ so once you get use to the syntax it's not too bad and Ii have had good success with it. But, my god has the number of features increased and it's easy to get lost.

Anyway, I have decided to go with option 2 and added a value textbox. The value textbox is only for visual reference. You can't enter in a value into it. I did this to save myself some coding for correct numbers being entered. 

However:
One can chose individual cells and enter a value in them and/or,
One can hold down the control key and select different cells you want to change the value of using the Up/Down value changer and/or,
One can click on the blank box with the right arrow before the first row value and select the whole row, also using the Up/Down value changer and/or,
One can select a range of cells by holding down the left mouse button and dragging it across the cells you want or,
If your not happy with the selected cells you can click on the clear button to deselect All the cells and zero '0' their values.

After this you click on the "Apply" button to set the values. Once your happy with the values you click on the save button, to save the values to the "timing.csv" file for uploading to the mcu's EEPROM.







There are 3 other forms; 1 for setting the Hall-Effects' settings, 1 for setting up the USB ports settings, and 1 for options which, I'm still thinking about.











For the options I was thinking about things like timing retard for starting and/or a rev limiter. Any ideas, anyone ????????

Cheers
Ray


----------



## 74Sprint

This is a better representation of selecting cells.


----------



## 74Sprint

I have decided to combine the Hall_Effect setting, Dwell, Rev Limiter, and Starting retard all on 1 page for simplicity sake.






I also wanted to show people what the difference in coding between typing in a number and using the number up/down buttons. Because I need to check and make sure that someone has actually typed in a number there are multiple steps to see if it is a number. I will still have to use the first batch of code for the "Timing Retard" (Rev-Limiter) and the "Idle RPM" text boxes.

Code for checking if a text value is a number:

private void txtBoxHall_Leave(object sender, EventArgs e)
        {
            string numString = txtBoxHall.Text;
            int number1 = 0;
            int valueT;

            bool canConvert = int.TryParse(numString, out number1);
            if (canConvert == true)
            {
                valueT = Convert.ToInt32(numString);
                if (valueT < 91)
                {
                    Console.WriteLine("number1 now = {0}", numString);
                }
                else
                {
                    txtBoxHall.Text = "0";
                    txtBoxHall.Focus();
                    MessageBox.Show("Number must be less than 91",
                                    "Error", MessageBoxButtons.OK);
                }

            }
            else
            { 
                Console.WriteLine("numString is not a valid int");
                txtBoxHall.Text = "0";
                txtBoxHall.Focus();
                MessageBox.Show("Must enter a whole number",
                                "Error", MessageBoxButtons.OK);
            }
        }

        private void btnSave_Click(object sender, EventArgs e)
        {
            btnUpload.Enabled = true;

        }

        private void txtBoxHall_KeyDown(object sender, EventArgs e)
        {
            //txtBoxHall_Leave();
            TextBox tb = new TextBox();
            tb.KeyDown += new KeyEventHandler(tb_KeyDown);

        }

        private void tb_KeyDown(object sender, KeyEventArgs e)
        {
            //txtBoxHall_Leave();
            string numString = txtBoxHall.Text;
            if (e.KeyCode == Keys.Enter)
            {
                //enter key is down
                Console.WriteLine("number1 now = {0}", numString);
                txtBoxDwell.Focus();
            }
        }

Code if I use number up/down buttons:

private void numUpDownHall1_ValueChanged(object sender, EventArgs e)
        {
            int X;
            X = (int)(numUpDownHall1.Value + numUpDown10Hall.Value);
            txtBoxHall.Text = Convert.ToString(X);
        }

private void numUpDown10Hall_ValueChanged(object sender, EventArgs e)
        {
            int X;
            X = (int)(numUpDownHall1.Value + numUpDown10Hall.Value);
            txtBoxHall.Text = Convert.ToString(X);
        }

_They both do the same thing, 50+ lines of code or just 12_.
Of course there is still lots of coding to do and cleaning up, and maybe make it look pretty.

Cheers
Ray


----------



## 74Sprint

I did a search for Free gauges that work with C# and serial data and came up with the below gauges. The website shows and says that there is a dial/needle face but it is actually only in the paid version. The gauges also include a demo mode which is cool. So what you see below is what I'm using for now.






Cheers
Ray


----------



## CFLBob

FWIW, to me, these are better than a swinging needle.   I'm assuming those squares or marks around the dial face aren't static but move as RPM and timing change.


----------



## 74Sprint

CFLBob said:


> FWIW, to me, these are better than a swinging needle.   I'm assuming those squares or marks around the dial face aren't static but move as RPM and timing change.


Yes

Ray


----------



## 74Sprint

Well I'm at the point where I need to get the computer program talking to the Nano and the Nano talking to the computer program.
Slowly getting there.

Ray


----------



## awake

Ray, if you run into any trouble getting the Nano to converse with the computer, and you are using the Arduino IDE, be aware that there are two different choices for the Nano; one is for the "old bootloader." I had to use that one for the Nanos that I have.


----------



## bluejets




----------



## 74Sprint

awake said:


> Ray, if you run into any trouble getting the Nano to converse with the computer, and you are using the Arduino IDE, be aware that there are two different choices for the Nano; one is for the "old bootloader." I had to use that one for the Nanos that I have.


Yah, all of mine except 1 are the same as your's, old bootloader.
The problem I'm having is that the serial com sends all characters as 8 bit characters and has to be converted into uint8_t (unsigned 8 bit integers) on the Nano side. Characters on the Nano side are only 8 bit characters, the Char is stored as a byte (8 bit) and indexing is by Byte so I can only receive up to 255 characters, when cleaned that makes it to 84.5 values stored. As far as converting them into uint8_t I'm using the 'C' atoi to do the conversion "timing_array(i)_ = atoi(strtokIndx);" This is the string of characters I'm sending but, in unicode (ASCII):

<,t,0,0,0,0,0,10,10,10,10,10,10,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,35,35,35,35,35,35,35,35,35,35,35,35,35,35,35,40,40,40,40,40,40,40,40,40,40,40,40,40,40,>

And this is the receive function:



		Code:
	

void Checkserial() //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++serialEvent
  {
    static boolean recvInProgress = false;
    static byte ndx = 0;
    char startMarker = '<';
    char endMarker = '>';
    char rc;

// While the serial port is available and no work is being done
    while (Serial.available() > 0 && newData == false) //
    {
// Read the serial buffer
        rc = Serial.read();
        if (recvInProgress == true)
        {
// Not at the end of the message
            if (rc != endMarker)
            {
// Store characters in the array
                receivedChars[ndx] = rc;
                ndx++;
                if (ndx >= numChars)
                {
                    ndx = numChars - 1;
                }
            }
            else
            {
                receivedChars[ndx] = '\0'; // terminate the string
                recvInProgress = false;
                ndx = 0;
                newData = true;
            }
        }
        else if (rc == startMarker)
        {
            recvInProgress = true;
        }
    }
// this temporary copy is necessary to protect the original data
// because strtok() replaces the commas with \0   
    if (newData == true)
    {
        strcpy(tempChars, receivedChars);
        parseData();
        newData = false;
    }
  }


The tempChars and receivedChars are also indexed by Byte. I've tried everything I can think of except, sending 2 strings and joining them into an array and save that to the EEPROM. There are 2 other strings I need to send one is the settings and the other is the engine temperature compensation. Both of those are much shorter and won't be a problem. 
So if you or anyone else has an idea, please let me know. In the meantime I'll try sending 2 strings.

Cheers
Ray_


----------



## 74Sprint

So I split the 100 timing cells into 2 and that is now working for uploading to the Nano. Sending 2 back-to-back strings of 50 cells. I'll have to remember this if I decrease the steps or increase the RPM range. I have found that I'll need to optimize the code for the Nano, I'm slowly running out of memory:
"Global variables use 1315 bytes (64%) of dynamic memory, leaving 733 bytes for local variables. Maximum is 2048 bytes."
I'll also optimize the PC program which, is just good coding. It mostly involves cleaning up unused variables or reusing some after zeroing them. So I now have 100 EEPROM locations holding my timing lookup table which gives me advance readings every 100 RPM to 10,000 RPM leaving me 924 locations for other stuff. The settings string only has 6 variables and the engine temperature compensation has 5. Not sure if I'm going to use celsius or fahrenheit or a choice of which. 

I was thinking of using 100, 120, 140, 160, and 180 degrees 'F' or 40, 50, 60, 70, and 80 degrees 'C' for the lookup points, any ideas/thoughts?

I'm only going to send back to the computer 3 readings; RPM, timing advance, and engine temperature, these will get updated between the interrupts.

Also I won't be using a MAP sensor on this version, just a mechanical advance replacement on this version, so no maxing out the engine load.

Cheers
Ray


----------



## 74Sprint

I just wanted to say that after some consultation that I will be patenting my code for converting the pulse width to RPM.

Ray


----------



## 74Sprint

Below is the attached PDF "Help" file for the PC program.
I'm looking for feedback from anyone who wishes to express their ideas, thoughts, and questions on it, thanks.

Thanks
Ray


----------



## 74Sprint

I'm going to be rewriting the Nano code using the time between pulses for getting the RPM and angular velocity. I'll then make that and the PC code available to anyone who wishes to use it for personal use.

cheers
Ray


----------



## 74Sprint

Just an update;
Well I believe I have both the PC & Arduino code Ready for testing. I'm sure that like any software I either forgot something or I didn't write something correctly and will need to be corrected. Hopefully it will just be minor things. The 4 stroke engine using wasted spark still needs to be refreshed but, I do have an old chainsaw 28cc that uses a really bad Walbro ignition and will not run so it's for testing. A 2 stroke is better than nothing right. It may or maynot hit the high RPM I'd like but, if it blows up I'm not out anything.

So what remains?
Just a  bunch of clean up stuff but, that can take time, sometimes more than one wants or needs, we'll see how that goes. I promise better videos. Need to make and solder up a proper proto board. Install the PC program to my laptop which, has none of the PC code or it's dependencies on it, so it will be a clean install. I like to do this because it's the only way I can tell if I compiled the code correctly for someone that does not have all the dependencies on their computer. All programs designed for Windows/Mac/Linux need dependant programs to work correctly and I have to make sure they get installed correctly with the main program. I also need to order some small cylindrical magnets and make an aluminum trigger wheel. For load/dyno I'll probably use an old 12 volt alternator and have it charge the battery at the same time. This also means I can use the clutch on the saw. As far as what the ignition is doing I have setup serial monitor in Arduino IDE, Gauges in the PC software, a timing light, and some testing instruments.

I have used up 52% of the available code memory and could use even more but, the more I use the slower or less time the mcu has to respond. Besides I think there is more than what most people need but, less than I would like. Afterall I do plan on using this on my 7.5 litre V8 racing engine, 6,500 RPM limit. Anyway this is what the LCD shows for reporting right now. The minus -127.00 Celsius means there is a connection problem with the temperature probe, I have it disconnected right now to show this. It reports back either C or F, your choice.






Cheers
Ray


----------



## 74Sprint

Well I got bugs, surprise, surprise, not. Did a little testing and found bugs in both programs and now I have to debug. I also have a bunch of other things I have to do this week so progress is going to slow down for a little while.

Cheers
Ray


----------



## william_b_noble

for what it's worth, there is a schematic and a short article on CD ignitions on my web page - I use one of that design on my 356 (that's a car, not an engine displacement) -I put a lot of miles on the car with that ignition, its very simple and reliable - but it does work with a distributor and breaker points.  WB Noble article published in Skinned Knuckles Magazine

the page with that article is here: WB Noble article page

there is no software in this circuit, no integrated circuits, just a surplus transformer, capacitor, some diodes, SCR and a couple of transistors.  no circuit board either ....   The way technology has changed over the last 45 or so years, no?


----------



## 74Sprint

william_b_noble said:


> for what it's worth, there is a schematic and a short article on CD ignitions on my web page - I use one of that design on my 356 (that's a car, not an engine displacement) -I put a lot of miles on the car with that ignition, its very simple and reliable - but it does work with a distributor and breaker points.  WB Noble article published in Skinned Knuckles Magazine
> 
> the page with that article is here: WB Noble article page
> 
> there is no software in this circuit, no integrated circuits, just a surplus transformer, capacitor, some diodes, SCR and a couple of transistors.  no circuit board either ....   The way technology has changed over the last 45 or so years, no?


Yup I know what a 356 is. I used to work with a german fellow that had one, we used to call it a 356 spider, not sure if it actually was one. As CDI ignitions there are a ton of different designs out there. Here is something very few people know is that the first example and working one was designed by a Canadian air force pilot back in the early 1950's. The design you show is still similar to the one he came up with. I've tried both the Hartley Oscillator & Colpitts Oscillator designs or variations of them but, I didn't like the consistency of them. My CDI design also uses 1,000 - 1,200 volts primary as compared to the 120 - 600 volt ones.

The main idea of mine here is to replace the mechanical advance as inexpensive as possible and stay within the limits of the mcu. I also want to use this design as a interface for standard ignitions. Another way to look at what I'm doing here is that it is a proof of concept for a coil-near-plug design. My final design of the CNP will also have a vacuum/boost reference and a faster MCU >=100mhz. 

Cheers
Ray


----------



## william_b_noble

Ray - you are trying to do something pretty different - in my case the circuit charges the capaictor to around 250 V, that's the typical primary circuit voltage on a spark coil ignition like the 356 (or my old doge) has - I tried higher voltages, it actually didn't work as well, no doubt due to longer recharge times.  My 356 redlines at 4500 RPM, so at two sparks per rev (it's a 4 cycle engine, right, and 4 cylinders),  that's 150 sparks per second - an easy rate for a modern all digital solution to meet. if you are running a 100 MHz clock and average 2 instructions per clock, you have over 300,000 instructions you can execute per spark - that should let you right one heck of a pile of sophisticated code.


----------



## 74Sprint

Well this project here is using a 18 MHz mcu and it can fire an LS1/2 (Inductive) coil up to 12,000 cam rpm so that would be 24,000 crank rpm. I know of racers that are using this as a single coil to 7,500 V8 rpm. The spark is actually quite descent up to 12,000 sparks per minute level but starts to die out after 12,500. My little CDI "Sparky" is a little beast but, took some tuning of components to reach the level it does. It can do 51,000 single sparks per minute. I do have a automotive racing ignition in the works that is actually 8 CDI ignitions in one and draws 54-56 amps and outputs 1,200 volts primary, it is also a coil-near-plug design. On a V8 it is capable of 48,000 crank rpm. I also have an inductive multi-spark ignition that draws 48 amps at max setting also tops out at >1,200 volts primary. But this puppy can only run for 15 minutes at max power setting. I've been waiting for 20 years for more reliable electronic components that are just now on the market that can handle the voltage and power. Thanks to electric vehicles. When this ignition is running at 75% power the fuel mileage on my 1976 Ford 302 truck increased by 30% and emissions decreased by @ 60%. I made these measurements using a 1 gallon (imp) jug (28 mpg) and my old tailpipe gas analyser which is now retired. It is a regenerative ignition so any left over energy is applied to the next spark and there is 3-6 sparks per firing not just a couple depending on rpm. We have had the spark top out at 120,000 volts (good for lighting cigarettes) measured with a high voltage probe I borrowed. I've had electrical and electronic engineers say there is no way it will work but, I have witnesses to the contrary. Yah I've been around for awhile and now that I'm retired I'm trying to commercialize some of my work and give a run at MSD. Ah I'll see how it goes.

Cheers
Ray


----------



## GreenTwin

74Sprint said:


> I've had electrical and electronic engineers say there is no way it will work


I have had so many people tell me that over the years.
Sometimes they are correct, but very often they were wrong.

The proof is in the pudding.
If you can make it work, then the EE's will do backflips trying to reverse engineer it into equations that explain it all.

Good luck.
.


----------



## stevehuckss396

I had gm engineers tell me that an engine with a  5/8 bore and stroke won't run on gasoline. Said I would need nitro. Guess what! My pal still has one of my #8 sparkplugs on his workbench with a .012 inch gap. Again they thought that wouldn't work. Guess what!


----------



## 74Sprint

Thanks guys. I have to admit if it wasn't for working on RADARs I probably wouldn't have thought of it. But, like anything else, "You won't know until you try".


----------



## CFLBob

The previous experiences from @GreenTwin and @stevehuckss396 reminded me of this great quote from Arthur C. Clarke.  Substitute "engineer" where it says scientist and then it goes along with what you guys say.

     “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”  
―    Arthur C. Clarke  

Ray - my last job before retiring at the end of '15 was designing the RF section of 10 GHz weather radars for commercial aviation, from small jets to Boeing/Airbus air transport planes.  What sort of radars were you doing?


----------



## GreenTwin

I often hear things like:

1. You can't do that.
2. You shouldn't do that.
3. That won't work.
4. If it did work, you should not do it.
5. How do we change our system so we can do that too?

I also hear:

1. We have never done it that way before.
2. Nobody does it that way.
3. Why would you change something from the way it is always been done?

etc., etc., etc.

When I hear "that is not the way we have always done it", I immediately think "no doubt there is a much better way of doing this", and very often I prove that.

There are many aspects of design.
Some of it has to do with UL listings, and how things are tested, and what may happen if you modify a device to operate outside of its design range.
It is never about breaking the laws of physics, but rather about finding unique arrangements for components and systems.

One story was in Scientific American I think, about an amplifier.
They build two components of an amplifier, and mounted them back-to-back.
There was an unplanned and unintentional induced feedback from one component to another, which produced a highly desirable effect in the amp.
Others tried to copy the design, and were baffled when their designs did not work the same, because the components were not mounted back-to-back.

Edit:

Another example is the story about the famous Russian rocket engine that outperformed any other rocket engine in the world.
The method that the Russians used for this engine was dismissed by NASA, and when NASA finally got ahold of one of these engines after the Soviet Union broke up, they discovered that they were 20 years behind the Russians in rocket engine technology.
.


----------



## william_b_noble

there is a very gratifying event, if you are able to produce it, and that is when you are a  young hotshot, and a room full of self-important senior engineers is working a problem, and you offer a soluton and their leader says "that is impossible" - I still relish the feel of the room, one hour later when I walked back in with a 6 inch thick printout and dropped in in the middle of the table and said "which part of this was it that is impossible?".  The "leader" was a leader no more after that.


----------



## 74Sprint

CFLBob said:


> The previous experiences from @GreenTwin and @stevehuckss396 reminded me of this great quote from Arthur C. Clarke.  Substitute "engineer" where it says scientist and then it goes along with what you guys say.
> 
> “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”
> ―    Arthur C. Clarke
> 
> Ray - my last job before retiring at the end of '15 was designing the RF section of 10 GHz weather radars for commercial aviation, from small jets to Boeing/Airbus air transport planes.  What sort of radars were you doing?


The RADARs I worked on were all ground based, ASR, IFF/SSR, PAR, Airport Ground/ASR, ILS, TACAN, and man portable. All of it was military except the ILS which was a Philips system. The TACAN is the military version of what the civilians call VDF or direction finder. Obviously I can't get into the details of the stuff but it was cool to be working on stuff that was 15 years ahead of the civilian stuff. The military paid a premium to have the 15 year head start, LOL the $5,000 shovel thingy. I guess you know about high power resonant frequency bursts then? Which inspired my 1 ignition. ASR had Pulsed, CW, and Doppler which was cool. I can honestly say 'stealth my a_s it is', LOL I can see you. I also worked on some phased array stuff and I'll leave it at that. I have seen and worked on some amazing stuff over the years that left a lot of people scratching their heads. After the military I went to work for the railroad and got my AAR electricians ticket and now I'm retired.

We can only create what we can imagine.

Cheers
Ray


----------



## 74Sprint

GreenTwin said:


> I often hear things like:
> 
> 1. You can't do that.
> 2. You shouldn't do that.
> 3. That won't work.
> 4. If it did work, you should not do it.
> 5. How do we change our system so we can do that too?
> 
> I also hear:
> 
> 1. We have never done it that way before.
> 2. Nobody does it that way.
> 3. Why would you change something from the way it is always been done?
> 
> etc., etc., etc.
> 
> When I hear "that is not the way we have always done it", I immediately think "no doubt there is a much better way of doing this", and very often I prove that.
> 
> There are many aspects of design.
> Some of it has to do with UL listings, and how things are tested, and what may happen if you modify a device to operate outside of its design range.
> It is never about breaking the laws of physics, but rather about finding unique arrangements for components and systems.
> 
> One story was in Scientific American I think, about an amplifier.
> They build two components of an amplifier, and mounted them back-to-back.
> There was an unplanned and unintentional induced feedback from one component to another, which produced a highly desirable effect in the amp.
> Others tried to copy the design, and were baffled when their designs did not work the same, because the components were not mounted back-to-back.
> 
> Edit:
> 
> Another example is the story about the famous Russian rocket engine that outperformed any other rocket engine in the world.
> The method that the Russians used for this engine was dismissed by NASA, and when NASA finally got ahold of one of these engines after the Soviet Union broke up, they discovered that they were 20 years behind the Russians in rocket engine technology.
> .


I use to work with a fellow named Joe Mazelli, bless his soul (RIP), said to me once "that's the way we have been doing it for 20 years". I said to Joe "did you ever think you were doing it wrong for 20 years?", he went silent.

Necessity or money is the mother of invention. We either figure it out, stumble upon it, or just look at it in a different way. I have been in meetings where someone suggests something, they get laughed at, at first but, then wouldn't you know it, they ended up being right. So I always try to keep an open mind.
Old age has given me knowledge and I hope wisdom.

Cheers
Ray


----------



## 74Sprint

william_b_noble said:


> there is a very gratifying event, if you are able to produce it, and that is when you are a  young hotshot, and a room full of self-important senior engineers is working a problem, and you offer a soluton and their leader says "that is impossible" - I still relish the feel of the room, one hour later when I walked back in with a 6 inch thick printout and dropped in in the middle of the table and said "which part of this was it that is impossible?".  The "leader" was a leader no more after that.


LOL, been there done that, unfortunately too many times. My most gratifying time was when I was still a private and found the problem with the rotary joint on the ASR RADAR, a $100,000 part (back in 1983) was changed out and modified on my suggestion. The lubrication ( organic grease) was interacting with the microwaves getting turned into carbon and the hard chrome finish on the roller bearings was getting blown right off like when you put aluminum foil in a microwave oven. They switched to my recommended lubrication and saved the government a $1,00,000 dollars that year alone. I got promoted to corporal, yippie The big engineers couldn't figure it out. Like really guys, do you really think that a rubber seal is going to stop all that energy.

Cheers
Ray


----------



## william_b_noble

74Sprint said:


> The RADARs I worked on were all ground based, ASR, IFF/SSR, PAR, Airport Ground/ASR, ILS, TACAN, and man portable. All of it was military except the ILS which was a Philips system. The TACAN is the military version of what the civilians call VDF or direction finder. Obviously I can't get into the details of the stuff but it was cool to be working on stuff that was 15 years ahead of the civilian stuff. The military paid a premium to have the 15 year head start, LOL the $5,000 shovel thingy. I guess you know about high power resonant frequency bursts then? Which inspired my 1 ignition. ASR had Pulsed, CW, and Doppler which was cool. I can honestly say 'stealth my a_s it is', LOL I can see you. I also worked on some phased array stuff and I'll leave it at that. I have seen and worked on some amazing stuff over the years that left a lot of people scratching their heads. After the military I went to work for the railroad and got my AAR electricians ticket and now I'm retired.
> 
> We can only create what we can imagine.
> 
> Cheers
> Ray


TACAN = Tactical Air Navigation (Wikipedia, on Tacan)  is really the Mil version of VOR (Very High Frequency Omnidirectional Range) which basically gave you the bearing from where you are to the station, often combined with DME (Distance Measuring Equipment) that would give you the range to the station.  VOR based navigation is mostly obsolete now that everyone has GPS, but it was common in and equipment to navigate using VOR (called RNAV or Radio Navigation) was a predecessor to INS based navigation.   I say this to try to correct VDF as an acronym and in some slight way differentiate TACAN, VOR, and DME.


----------



## william_b_noble

I'm sorry, I have a somewhat dry sense of humor, I read:



> do you really think that a rubber seal is going to stop all that energy.


and I would add "of course not, to do that you need a rubber chicken".


----------



## 74Sprint

william_b_noble said:


> TACAN = Tactical Air Navigation (Wikipedia, on Tacan)  is really the Mil version of VOR (Very High Frequency Omnidirectional Range) which basically gave you the bearing from where you are to the station, often combined with DME (Distance Measuring Equipment) that would give you the range to the station.  VOR based navigation is mostly obsolete now that everyone has GPS, but it was common in and equipment to navigate using VOR (called RNAV or Radio Navigation) was a predecessor to INS based navigation.   I say this to try to correct VDF as an acronym and in some slight way differentiate TACAN, VOR, and DME.


Yah there are different names for it. But they all basically did the same thing which was to tell pilots the direction to the airport and most did the range and station ID. Don't forget there is also the marine version also. Here is a quark for TACAN; they are vacuum tube based for the reason that an EMP will only knock them out temporarily and they will recover, unlike IC based equipment. Even if the IC equipment is radiation harden. There is a aero supply company "Aircraft Spruce" that I get some metal and stuff from and they pretty much only supply GPS navigation stuff now.


william_b_noble said:


> I'm sorry, I have a somewhat dry sense of humor, I read:
> 
> 
> and I would add "of course not, to do that you need a rubber chicken".


LOL so true.

Ray


----------



## Richard Hed

william_b_noble said:


> I'm sorry, I have a somewhat dry sense of humor, I read:
> 
> 
> and I would add "of course not, to do that you need a rubber chicken".


I use a rubber ducky.


----------



## william_b_noble

geez, the rubber chicken comment makes no sense with the blank quote box - score one for the computer - in the blank quote box for what I read, it would have a quote from upthread about a rubber seal


----------



## stanstocker

william_b_noble said:


> geez, the rubber chicken comment makes no sense with the blank quote box - score one for the computer - in the blank quote box for what I read, it would have a quote from upthread about a rubber seal


Tossing a rubber chicken into the mix ALWAYS makes sense, even with no context 

I guess you could make one with silver fiber fill and use it for an RF gasket of sorts for those who do need context...

Cheers,
Stan


----------



## 74Sprint

All that was needed was to use a bearing with a flat stainless steel seal that is used quite commonly now in all sorts of things, like high temperature and food processing environments.

Ray


----------



## firefite

74Sprint said:


> The simplest ignition I can come up with besides points.
> Just a quick update on the LS1 smart coil and driver board. I tested the coil a bit more and the required driver components. It will work with just a Hall-effect but it's not consistent. To correct this a PNP transistor is needed to drive the spark signal. The signal drives a transistor inside the coil so more current is needed. I went to a 1K ohm pullup resistor and I don't want to go below that because the Hall-effect or most of them can only handle 20ma of current. I could go down to 600ohms for 20ma. I did notice that just like older GM designs it needs to see a positive going pulse to trigger. The board is 17mm wide and 26mm long. C1 should be 0.01uf to 0.1uf ceramic depending on Hall-effect used. In the setup below the coil will fire after the magnet passes the Hall-effect or when the LED turns off. No dwell control or limiting resistors are needed because the coil handles all that. Just add a Hall-effect, 12 volt supply, and a LS1 smart coil. You don't have to use the 2N4403 (PNP), you can use something similar. I used it because I had them.
> 
> View attachment 129366
> 
> 
> View attachment 129368
> View attachment 129370
> View attachment 129371
> View attachment 129394
> 
> 
> View attachment 129393
> 
> 
> I included a pdf below that can be used to turn a CD disk into a timing wheel. I have others to share with timing events. If there is enough interest I'll get extra boards made. Oh I also cleaned up the board design a bit, things like better pours and changed Q1 to a wide T092 pad.
> 
> Cheers
> Ray


Did you ever get anymore boards made? I'd be interested. Dave


----------

