Position sensor for a timepiece setting stem

摘要

A capacitive sensor is described for determining the instantaneous angular position of a rotatable element (3) in a timepiece, such as the setting stem of a wristwatch. Static electrodes (11, 12, 13, 21, 22, 23) are arranged to form, in conjunction with rotor electrodes (5a, 5b) of the rotatable element (3), a first differential capacitance pair (1) and a second differential capacitance pair (2). A sensor calculation unit is configured to sense difference values from the differential capacitances pairs (1, 2) and to evaluate the angular position of the rotatable element (3) from the difference values using predetermined information relating the differential capacitance values to angular position values.