Pendular accelerometer sensor with conditional capacitive detection

An accelerometer sensor, comprising a casing, a pendulum fixed to the casing, a movable electrode carried by the pendulum and connected to a detection circuit, fixed first electrode and second electrode integral with the casing to form, with the moving electrode, two capacitors of variable capacitance depending on a distance between the electrodes, and a control unit configured to perform detection operations to measure the variable capacitances of the capacitors and a control operation of the movable electrode depending on the capacitances measured by applying a logic signal that controls a switch for selective connection of the fixed electrodes to a drive circuit delivering a control signal to the fixed electrodes to keep the pendulum in a predetermined position, wherein the control unit is configured to apply, at each calibration period, a first detection signal at one of said fixed electrodes chosen according to a logic level of the control signal, and a second detection signal at the other fixed electrode, the control signal being applied to the electrode at which the second detection signal is applied.