Patent ID: 6229299
Filing Date: 2001-05-08
Classification: G01P

Abstract:
A system for sensing the rotational velocity and direction of an object about a rotational axis, the system comprising:a magnet fixed to the object whose rotational velocity is to be measured;a first non-contacting sensor, said sensor producing a first signal which is a function of the strength of the magnetic field emitted by said magnet;a second non-contacting sensor, spacially displaced from said first non-contacting sensor, said second non-contacting sensor producing a second signal in response to proximity of said magnetic object; andan electronic controller, said controller receiving said first and second signals, calculating a derivative of said first and second signals, determining which of said derivatives of said first and second signals is greater and using that derivative value to calculate the rotational velocity of said object, and calculating a direction of said object as a function of said derivatives of said first and second signals and the value of said first and second signals.