> >These sensors are inductive? So basically there is a metal
> >gear, and the sensor senses each tooth?
> >
> 
> Yes, they are inductive and therefore a PITA to interface to, as the
> amplitude increases with wheel speed and the waveform changes polarity when
> the tooth moves away from the sensor. Your interface circuit has to be able
> to deal with all this to reliably detect the crossing point.  IC's
> specifically for this application exist of course, but the hall-effect
> sensor refered to in another post looks like a much nicer solution.

A VR sensor is the preferred method...all OEM's stopped using hall
effect stuff in the early 90's. Attaching magnets to stuff might pose
a problems with respect to balance and other aspects of the mechanical
system.

I've been working with VSS sensors on automobiles lately and have
realized that they are robust little sensors. The LM1815 is a very
nice IC to use and solves all your noise and signal issues.
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