PDF's L-cheapo ignition

[bluejets]

Watched a series of videos from Doc1955 and built up details of his ignition from what he had shown.
Made up a series of pdf's of his circuit and have them here to post if all ok.

I found what I imagine is an original as well so same goes for that. Don't know exactly where it originated but Doc's videos seem to show it as fairly reliable.

I also made a different version using an MJ10012 darlington in place of the original TIP120 and have both a single and "stackable" double pcb version here.

So if all OK I'll pop it in here for everyone.

 

[bluejets]

No objections so here are the files.

 

[ruralearl]

Hello bluejets, Thank you for posting these. Regards, Earl

 

[Rudy from Norway]

Are there any schematics available?
Rudy

 

[bluejets]

Are there any schematics available?
Rudy

It's the first in the pdf's.(L-cheapo Ignition Circuit)

 

[tornitore45]

Q3 gets full 6V battery across the E-B junction, it will blow up instantly.

 

[XD351]

Q3&4 are not transistors , they are Hall effect units and the pins should be labeled from left to right on the schematic -
VCC - GND - OUTPUT.

 

[bluejets]

Q3&4 are not transistors , they are Hall effect units and the pins should be labeled from left to right on the schematic -
VCC - GND - OUTPUT.

Yes correct, however I did not draw the "original" circuit so there ya go.
If one looks at my drawings it is clearly seen as hall effect with the terminal markings quoted.

Never ceases to amaze me how some can miss the obvious written clearly on the "original".....
Q3 and Q4 are Hall-effect transistors and are operated by the passing of a small magnet.

 

[propclock]

I am a major fan of Dave Sage's and friends ignition design.
IGBT's specifically designed for coil driving what a concept!
with a timeout. The time out stops you from frying your coil etc
when the points or hall are left closed. I have made many of these units. They work exceptionally well. I have made ~30 of them.
For myself and members of BAEM.
Highly recommended and fully tested. Search a new ignition on this site.

Here is the link
https://www.homemodelenginemachinist.com/threads/a-new-ignition-circuit.20415/page-4
thanks again Dave. Love it.

 

[TonyM]

Me too. I have made several of these and the only fault was my soldering. They worked out at less than 20Euro each.

 

[tornitore45]

Never ceases to amaze me how some can miss the obvious written clearly on the "original".....

A schematic should contain all the information necessary to convey the functionality without written notes. One may have some text explaining construction details but the schematic symbols and their interconnection should suffice to define for those skilled in the art to understand function and evaluate performance. That is so for each of the 100's of schematic I draw professionally.

 

[bluejets]

A schematic should contain all the information necessary to convey the functionality without written notes. One may have some text explaining construction details but the schematic symbols and their interconnection should suffice to define for those skilled in the art to understand function and evaluate performance. That is so for each of the 100's of schematic I draw professionally.

What you seem to fail to recognise is most of the supplied details are from modellers who treat it as a hobby.
Most will do their utmost to supply as much info as possible and correct and queries which are overlooked.
Best thing you can do is give others some leeway and not be so damned critical.

 

[tornitore45]

My original post was not critical. Pointed out the the transistor, that turned out not a transistor, would blow.

Bluejet wrote:

Never ceases to amaze me how some can miss the obvious written clearly on the "original".....

My last post was a response, you consider critical, to your snarly comment

 

[Richard Hed]

A schematic should contain all the information necessary to convey the functionality without written notes. One may have some text explaining construction details but the schematic symbols and their interconnection should suffice to define for those skilled in the art to understand function and evaluate performance. That is so for each of the 100's of schematic I draw professionally.

Absolutely. If you have ever dealt with dwgs that are incomplete or worse, never intended to be complete in the sense that WE mean, you would understand how simple that seems. I am dealing with drawings,very old, that have most of the main, what we might consider the salient parts, with dims. However, the lack of important dims makes me thimk that in the old days peeps simply added or subtracted whatever they needed or wanted. Not sure if that is true, just supposition.

 

[awake]

I have no idea if this is what is going on with old drawings, but I find that when I'm making my own, I tend to leave out dimensions that are not critical - for example, the radius of a corner round, where it really doesn't matter if it is .125" or .25" or 6mm - it's just for looks and to avoid sharp corners that can bite. But when preparing drawings for someone other than myself, I probably need to include that ...

 

[Richard Hed]

I have no idea if this is what is going on with old drawings, but I find that when I'm making my own, I tend to leave out dimensions that are not critical - for example, the radius of a corner round, where it really doesn't matter if it is .125" or .25" or 6mm - it's just for looks and to avoid sharp corners that can bite. But when preparing drawings for someone other than myself, I probably need to include that ...

Yes, of course, but I see drawings that don't have what really ARE critical dims that are missing. In the old days there weren't any standards and nowadays we thimk of these drawings as very crappy--the dims are placed all over the place, either not dimmed at all or dimmed more than once. Even so, it is a fun challenge to work them out.

 

[awake]

Ah, gotcha. Well, in that case, maybe it has to do with the other thing I routinely discover on my own drawings ... I just forgot to put it in.

 

[Richard Hed]

Ah, gotcha. Well, in that case, maybe it has to do with the other thing I routinely discover on my own drawings ... I just forgot to put it in.

Yeah, well I do that too, but these ones seem to be systematically missing, poorly arranged, difficult to find, in unusual places. Of course, that is from OUR viewpoint in time 120 years after the dwgs were made.

 

[tornitore45]

Dimensioning a part is an art few people master.
Even when the part is fully dimensioned one has to do lot of calculations and sometime trig in order to machine the part.

Then there are bad habits like making the dimension line touch the part. On a complex part one does not know which line defines a part edge because the edge appears to continue. Part lines should be heavy, dimensions light.
Excessive display of hidden lines may make the drawing confusing, add another view or a crossection.

When adding dimension I start to add the dimension that define the blank.
Then I imagine to machine the part and add the dimensions defining the first operation, and so on until the last detail is defined.

Is not unusual for me to redraw a part and add the dimension as they are needed for the work not just to define the geometry

 

[Richard Hed]

Dimensioning a part is an art few people master.
Even when the part is fully dimensioned one has to do lot of calculations and sometime trig in order to machine the part.

Then there are bad habits like making the dimension line touch the part. On a complex part one does not know which line defines a part edge because the edge appears to continue. Part lines should be heavy, dimensions light.
Excessive display of hidden lines may make the drawing confusing, add another view or a crossection.

When adding dimension I start to add the dimension that define the blank.
Then I imagine to machine the part and add the dimensions defining the first operation, and so on until the last detail is defined.

Is not unusual for me to redraw a part and add the dimension as they are needed for the work not just to define the geometry

Oh yes, for sure. However there is ONE modern convention I truly disagree with, and that is because I am both a draftsman AND a machinist and that is the convention of not dimming the last dim. What this does is forces me as a machinist to get out my calculator and waste time figuring it out. Had it been in already, I could just proceed in machining.