Hall Effect sensor

[neil_1821]

I was wondering if anyone can shed any information on these?

I'm currently building the hoglet and the website listed on the plans no longer exist and google searches tend to bring up sensors for cars. Can anyone point me in the right direction on where to purchase or if it's possible to make one?

Cheers

 

[Swifty]

I would have thought that any electronics shop would have them. Where are you based ?

Paul.

 

[neil_1821]

Hi Paul,

Based in Leicestershire in the UK so we have the likes of maplins etc

The other thing is, i'm not really sure how they work. Do all hall effect sensors work off detecting the magnets that are placed on the crankshaft gear? and how are the ignition leads wired into the hall effect sensor?

 

[deverett]

Apologies for bumping into this thread, but th OP's question brings up a couple more on this subject that I've had on my mind for a while:

1. Will 'any old' Hall effect sensor work?
2. How do you find out which is the S seeking pole of the small magnets (I understand that it is the S seeking pole that has to face the Hall sensor)?

Dave
The Emerald Isle

 

[Jasonb]

Plenty on e-bay.co.uk which is where I have got them in the past, used this guy

http://www.ebay.co.uk/itm/A3144-A31...MAGNETIC-DECTECTOR-UK-BRAND-NEW-/190823658126

Neil, as MJN are no longer trading if you want a whole ignition system then the one from S&S made specifically for the Hoglet has all you need. towards bottom of left column

http://cncengines.com/orderpage.html

Dave wave the sensor over the magnet and it will only work with the correct end facing it. The likes of S&S mark their magnets so you know one end from the other.

Most sensors will pick up teh signal but would depend on the ignition circuit to some extent I would think

 

[Swifty]

The South Pole is the end that I use to trigger the sensor, the North arm of a pocket compass will point to the South Pole of the magnet, here is a link explaining things. https://www.kjmagnetics.com/blog.asp?p=which-pole-is-north

The sensors only work one way around, so you may have to turn it around to get the right orientation.

Paul.

 

[jimjam66]

Forgiver my ignorance (jeez I've been saying that a lot lately) but would something like this work? I have very little idea what would constitute decent CDI ignition, nor in fact whether the terms 'CDI' and 'Hall Effect' are interchangeable. And yes, I know the link above is for a single spark plug where the Hoglet calls for a twin spark plug unit, but I'm thinking about a H&M unit which only needs a single spark plug myself.

 

[tornitore45]

There are many Hall Effect Sensors available, some are better suited that others.
First consider the Supply Voltage it can vary from 5V to 24V, next check the output max voltage to be compatible with the trigger circuit.
Most importantly some sensor need a flux reversal to flip to the other state, in other word once they have seen the South pole and switched ON they must see North pole to turn OFF. This type is not suitable for ignition applications.
What you want is the type that switch on with a strong South ans switch off when the flux drop to a weak South and are certainly off at zero flux. I found the TLE4805 suitable and inexpensive. Datasheet attached

View attachment Hall_Sensor_TLE4905L_OnHand.pdf

 

[neil_1821]

Thanks for all the links and info

I will have a proper read later on today as I'm currently at work, but happier now I've got some information on the subject.

 

[Jasonb]

David, the CDI is the whole ignition system and the hall sensor is just the "switch" that triggers the spark, a simple contact could also be used on may CDIs.

The one problem with a lot of the Rcxel units is they have an auto advance feature which can give timing problems on our slow running engines especially as they are based on engine revs and only get half the speed reading if the magnet is on the larger timing gear.

I personally don't like the thick heavy metal shielded spark cable which uses the outer as the earth as they look overscale on models. Better to get one with separate earth and then use old style cotton insulated cable on a hit & miss or if its for an aero engine the thin silicon insulated wires and small plug caps.

In the UK you could also look at http://www.minimagneto.co.uk/Products.php

 

[Swifty]

David, I used a similar ignition on my Nemett Lynx, but I had to put 2 magnets on the end of the cam shaft to get proper revolution count for the advance. It worked well on that engine.

Paul.

 

[jimjam66]

Thanks for all of the help. And Paul, thanks for the experience on the Nemmett Lynx. I'm not too fussed about the thick plug lead, but could easily cut it shorter and replace it with other wires if it annoyed me too much. Can't really justify more than double the price just because the leads as supplied aren't ideal.

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