Ign Module /Rev engineering

Hi Guys, My problem is the lack of avalability of an IGN module that replaces points on small old engines. The one ive dismantled is branded Atom Ign module, these are nolonger manufactured since 2005. They were invented & manufactured by 2 brothers in Australia. There patent was lodged in 1979 under 4163437. I would assume this has expired. Is it ok to ask for help on this cicuit on this Forum, as i need to construct a couple for my engines. There is only 6 components in it.

I have seen moderators go both ways on ignition systems. Sometimes, it seems the HV aspect has gotten the thread closed. Other times, it hasn't.

I suggest giving a little more information. Is this an ignition for a car, motorcycle, tractor, model, etc.? Is it 12V or some other voltage?

How many cylinders?

Are you open to the newer advances since 1979? And/or, why can't you use a more modern ignition?

John

Hi japanhalt, dont know why it posted twice as the first one my puter said it didnt post!!!. Its for old single cylinder motors which use points which may nolonger be avalable. Ive found the modules work exelent but not av anymore & its very compact. Posted pic of the circuit & CRO wave form but was rather distorted in photograph so have drawn on circ what it realy looked like. The cicuit works by Q2 turning Q1 off when trigered. The resistors were deposited on to a ceramic substrate which broke when dissasembled. R1 i think was1.5K can any body work out what R2 & R3 values are. Thanks as im not very good in the desighn area.

Should be an interesting project.

If you post something and hit the "back" button, the front page will be not show the new activity. You have to hit "refresh" to get your post to show.

#12 said:

If you post something and hit the "back" button, the front page will be not show the new activity. You have to hit "refresh" to get your post to show.

Click to expand...

Actually, I think there is a small glitch in the software. I and others have had similar problems. In my case, I occasionally get an error indicating my submission didn't post. When I exit and renew the site, the post appears. I ended double posting something recently because of that, and a moderator quickly fixed it.

I assumed something similar happened to debe.

John

debe - are you sure that 'Q1' isn't a Hall sensor? The modules that I have used have to be positioned to have the flywheel magnet pass by them.

Ther is something missing...like where the power voltage is connected and how Q1 is triggered, along with the questions in post #2.

This module has only 2 leads one goes to GND other goes where ign points were conected to coil primary. No hall device can be mounted any where, power is from coil when magnet goes past it. Pictures are of the dissasembled unit & wasnt easy to dissasemble, hence the ceramic substrate is in 3 pieces & cant measure res values. Need these values to try & replicate the unit. Yes John thats what happened the computer said it wasnt posted.

I have seen similar devices. The question is whether you will retain the mechanical "points." A lot of modern ignitions use other methods to sense when to fire. You mention in post#3 that points were no longer available.

John

Edit: Okay, I re-loaded the image, but I just noticed that you are dealing with a magneto ignition, so this won't work anyway.

Post a pic of the instructions, you disconect the points. Currently runing one on a single cylinder Tohatsu 5HP aircooled outboard. BillO cant see the pic just a box with a red X. They had a range of these things colour coded for different timing, I asume the C1 capacitor altered the timing.

Think ive worked out the remaining resistor values. Measured across the 2 leads of the module @ 2K ohm. My guess was R2 1.5K & R3 470ohm, so using spider web bread boarding since there was only 6components, i hooked it up to my tesd bed & ran it with a electric drill. Found by adding a capacitor for C1 trial & error found value of .47uf gave a good fat spark at low & high RPM. Next test was on the Tohatsu O/B & it works fine & does advance the timing by 3Deg over the points but thats ok. All i need to do now is make a more tidy unit out of it & probably set it in ressin. Also if the ign coil is mounted on the outside of the fly wheel the module polariyt is swaped over.

Hi Debe,

Do you have any specs. on the Darlington?

pilko.

Not just yet pilco, the one im using came out of a Ford car engine computer that had 3 ignition coil driving darlingtons in it to drive 3 ign coils, the ECU was a Bosch unit i picked up for free from a wrecker. the transistors just had a Bosch code on them. In the process of trying to find a comercialy avalable type of transistor & test it out. Some one might have sugestion here?

You might consider an MJ10012 Darlington. Perhaps overkill for a small engine, but they are specifically designed for automotive ignition.

TIP122, TIP132, TIP142 might work as well. They are rated for 100v instead of 400v, but are more common.

Interesting and simple solution, I must say.

Thanks SgtWookie will look into those transistors.

Used a BD649 transistor Ic 8A Vceo 100V. Hadone on hand but the TIP series transistors mentioned by Sarge are good to use. The system still drives a tacho same as if it was a points system. Pic of my first module which i will set in ressin. Cost of parts here in Aust about $3.

Engine idling at 2000 RPM or is that just a test?

Definitely the simplest points replacement I've seen.