Patent ID: 6965327

Claim:
Device for evaluating a useful signal having a value, the useful signal originating from a proximity sensor, wherein the value of the useful signal changes with an approach of an object to the proximity sensor and with a removal of the object from the proximity sensor and wherein direction and amount of this change are characteristic of at least one of direction, speed, and distance of the object, comprising: a first recognizing means having an output which changes from a first switching state to a second switching state when a first value of the useful signal, or a first value of a first signal generated from the useful signal, exceeds or falls below a first limit value which is characteristic of the object approaching the proximity sensor; a second recognizing means having an output which changes from a first switching state to a second switching state when a second value exceeds or falls below a second limit value, which is characteristic of at least one of the object approaching the proximity sensor and the object being removed from the proximity sensor; a first deciding means coupled to the output of the first recognizing means and the output of the second recognizing means, and having an output which changes from a first switching state to a second switching state when the first recognizing means changes its switching state and when the second recognizing means maintains its switching state, and wherein the first deciding means remains in the second switching when the second recognizing means maintains its switching state for a predetermined first time slot after the switching state of the first recognizing means has been changed; a time detection circuit having an output, the time detection circuit being coupled to the output of the first deciding means, the output of the time detection circuit being set to an active state when the output of the first deciding means is set to an active state for a time slot which is longer than the predetermined time slot; and a second deciding means coupled to the output of the time detection circuit and being set when the output of the time detection circuit is set to its active state.