Andre...I am assuming that your are looking at one of the coils on your sensor motor. When you say "Odometer" are you driving a mechanical counter? (BTW Why do you need a sensor motor, a stepper motor gives very precise position control and all you'd need is maybe a optical sensor for the Zero position).
In that case your waveform makes sense....stepper motors make a "step" movement very quickly and are then more or less stationary till the next step. So what you're seeing are spikes induced by the movements of the magnet in your sensor stepper motor - first positive and then negative. This makes even more sense when you see that the intermediate spikes are of less amplitude than the higher ones - the higher ones occur when the magnet is right on the winding that you are looking at, the lower spikes are when it is on an adjacent winding.I may be completely off track here, but from your explanation of what you're doing, the above makes sense.Let me know if I am missing anything or have misinterpreted your question?Cheers // David
