mister_e ... and others.

I am monitoring the p-lead of the magneto. It's a wire which allows the primary coil to be grounded and thus the spark shuts off. The secondary of the coil feeds the plug leads ... through the distributor

I can't get to the plug leads and the p-lead is shielded all the way from the magneto to the kill switch. My only source of pickup is the point where the p-lead connects to the kill switch.

After experimenting today with a dual stage comparator/filter circuit I think I am pretty close. Tomorrow I will replace my diodes with Schottky's as I am getting too much of an overshoot on the negative pulses ... (about 0.8v) which is sufficient to give intermittent false triggers on the TTL inputs. Don't have any Schottky's in my Box 'o Trix. This may just do it; but I am still open to better ideas .... many have done this so it's no rocket science. Just needs to be resolved.

Thanks,
Shane