Magnetic Ignition pick-up?

What would be the best way to use the signal from an automotive distributors magnetic pickup and interface it with a Pic 16f877a? The distributor is sitting on my desk and it won't be used on an engine. I have tried using the comparator module as a zero crossing detector but I get to many false trips. With the internal voltage reference at ~1.5v I still get too many false detections. I have tried hooking the two coil wires to the - and + sides of the comparator with a 10k resistor in series and a 1u cap. across the leads and also with one side of the coil and comparator tied to ground and the other wire to the + comp. input.

Go to the first post of this thread. BigBoat also has a TCI site. Both interface a Hall detector to a 16F628, which should be similar to your application.

John

If you are using the in built pickup, then you want a reluctance sensor amp. I used to use the LM1815, but it might be replaced with something better by now. It's an adaptive amp with zero crossing detection in built. Does everything for you and provides a clean signal. You might want to do some google searching on reluctance sensor chips or check national semi site to see if they have any cross reference links for something updated.

Well, it's not listed as obsolete, which is a good sign.
**broken link removed**

EDIT: You can get its latest version from Digikey -
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=LM1815N-ND

The only problem with that app. is that it uses a Hall Effect sensor. The sensor I'm using is from the older H.E.I. ignition that just gives you the two ends of the coil pickup. The problem is that when there are no rpm I get a lot of false triggers, but as the rpm increases the false triggers decrease. Here is a snapshot from the oscilloscope of the wave form. Could anyone offer any advise on how to use this signal reliabley?

**broken link removed**

Is another IC the only way? (yeesh, more parts... )

Thanks, DirtyLude. After a bit of searching I found this.
https://www.psocdeveloper.com/uploads/tx_piapappnote/an2301_01.pdf
I will try this schematic of the sensor and see if I get better results.