Patent ID: 7106054

Claim:
A device for sensing the rotation of a member rotating about an axis XX′, said device comprising: m proximity sensors situated in a plane perpendicular to the axis XX′ and in m radial directions, m being an integer greater than or equal to 2, a mark fastened to said rotary member and eccentric to the axis XX′ being adapted to modify an amplitude response of said proximity sensors when said rotary member rotates, an excitation circuit adapted to excite said proximity sensors, each of said sensors supplying an excitation response when it is excited, comparison means for comparing an amplitude of the excitation response of each of the sensors with a comparison threshold value during a time period referred to as an observation window and to supply a logic level 1 or 0 when said amplitude response is greater than or less than said comparison threshold value, means for identifying a movement of said mark past one of said sensors as a function of the value 0 or 1 of said logic level, and resetting means for resetting said comparison threshold value or said observation window characteristic of a sensor by means of successive iterations using the value 0 or 1 of said logic level when said mark cannot be at the location of said sensor.