Independent dual ignition with a long tooth?

Forum for discussing how to install MicroSquirt(TM), choose and troubleshoot sensors, wiring, and communications for MicroSquirt (TM) and MicroSquirt Module(TM).
Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
triangles95
MegaSquirt Newbie
Posts: 33
Joined: Mon Dec 14, 2009 9:32 am

Independent dual ignition with a long tooth?

Post by triangles95 »

I want to use Dual Independent Ignition setup on my motorcycle. The motorcycle is a 180° parallel twin. I have two 180° opposed vr sensors with one long trigger tooth on the flywheel. I believe I need to trigger off the leading edge of the tooth since the long tooth gives a large error in the zero crossing. I have the v3 microsquirt controller. I have not found any useful information in the manual on how to deal with a long tooth. The manual mentions that it has an improved ignition circuit but I didn't find any details as to if it would be helpful dealing with a long tooth. I've read mentions of an "edge detection circuit" that can to be added to the input to compensate for a long tooth. Is such a circuit necessary with the V3 controller? I guess I'm asking is where do I go from here to get this to work? I cannot find enough information to figure out how to deal with a long tooth.
socrace
MegaSquirt Newbie
Posts: 3
Joined: Sun Dec 08, 2013 12:45 pm

Re: Independent dual ignition with a long tooth?

Post by socrace »

Microsquirt can't read a single tooth wheel using a vr sensor.

This means very few motorcycles from the 70's and 80's will work with microsquirt in dual spark mode, unless the sensors are replaced with hall sensors.

This is because Micosquirt's internal vr chip (max9926) uses a mode with a 85ms watchdog, so output is just random noise while at cranking speeds.

I know this is an old post, but thought it'd be useful. In fact really, really wish I'd known this before spending several days trying to get it to work!
Post Reply