>I think you'd be way better off epoxying a small magnet to your harmonic >balancer and mounting a Hall Effect sensor to read it. Hmm, only give one pulse per revolution. I would look at something that would sense the starter ring gear teeth - lots of pulses per rev. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist