How do Atom Computer Ignition modules work?

[Mumbles]

quote legendre:

So how the heck does it work? :geek:

How do they work? Really good! 😀

Someone in the past once explained how the different components in the different modules know when to correctly trigger the ignition coil. Hopefully they will see this and explain it again.

[mercuryman]

Mumbles have you made and used a Module from the above drawing? I priced the parts on Ebay and could build 10 for $40.49.

[mercuryman]

Mumbles did you build one of the Red modules from the drawing. I priced the parts on Ebay and I can make 10 for $40.49.

[debe]

If you go to Photo bucket debe5 there is a video of my home made module on a running Victa 2stroke lawn mower. Also pictures of my outboard with the module on to see if they worked & they do. If you want to go in to the theory of how they work, read the US patent refered to in a previous post. It has taken me over 2 years to find a suitable transistor (2SD1071) that would work in this circuit. I found on some Ignition systems the transistor would break down. To over come this I added the 15KE200A to reduce the high voltage spikes. This then made the module reliable.

[Mumbles]

quote mercuryman:

Mumbles did you build one of the Red modules from the drawing. I priced the parts on Ebay and I can make 10 for $40.49.

No, those are Debe’s pictures of his module.

That’s totally out of my league to try building something like that. Maybe I’d attempt it after eating a truck load of carrots and my vision improved. 😉

[mercuryman]

Debe, I’m not to good with Photo Bucket and can’t find your video. I think you know what you are doing and I am going to make some and see how they work for me. I am thinking of putting 2 in one small case and run 2 leads to the mag. and ground wire to the block.

[legendre]

@debe

Had you tried using a device like the MJE13007A? That would be my go-to for this application – they are cheap and very plentiful. The 13007A are 400V Vce vs. 450V, but that shouldn’t be any matter, as the the protection diode you’re using clamps at 275V – well under the 400V limit.

I’m asking mostly, as I have plenty of them in-stock.

[Mumbles]

Here it is.

http://vid172.photobucket.com/albums/w3 … bf2100.mp4

[debe]

Hi lgendre, no the MJE13007A wont work because its not a Darlington type transistor so its gain (hfe) is too low. Ive tried a lot of transistors & failed until I found & tried 2SD1071. They are cheep I purchased 10 of them for $12.87 + $4.95 freight on Ebay from China. I suspect the Atom module used a custom made darlington transistor as it just had (atom A1) on it.

[debe]

Mercuryman, Before you make a double one with a common ground, try a single one first to find which polarity the module needs to give a reliable spark. It depends entirely on the type of ign coil & its polarity. Even with the original Atom modules the polarity was trial & error. Also makesure the switching transistor is insulated from the heatsink. I used silicon rubber insulators.

[Author]

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