> > (I am designing a bicycle speed sensor right now for a client.) > > > > Everyone uses reed switches for bicycle wheel-speed sensors. > > Not true. I have done commercial bicycle speed sensors too. Still in production? (If they got that far). Hard to beat simple, cheap, quite reliable & zero power. Tony -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist