Capacitive sensor with optimized noise immunity

A capacitive proximity sensor comprising a detection circuit, comprising a detection capacitor, a storage capacitor and switches, and a microcontroller which is configured to control the switches of the detection circuit in order to perform measurements for detecting whether or not a human is present in proximity to the sensor, each measurement comprising the alternation of a first acquisition phase and of a second acquisition phase over a constant period, said first acquisition phase comprising the charging of the detection capacitor then the discharging of the detection capacitor into the storage capacitor in order to obtain a voltage value across the terminals of the storage capacitor by analog-to-digital conversion, said second acquisition phase comprising the charging of the storage capacitor then the discharging of the storage capacitor into the detection capacitor in order to obtain a voltage value across the terminals of the detection capacitor by analog-to-digital conversion, the microcontroller being configured to perform measurements in a repetitive predetermined sequence, said sequence comprising a series of N consecutive measurements, N being a natural integer greater than or equal to three, wherein, with the period between two consecutive analog-to-digital conversions of the first measurement of the series being called a reference period, the period between two analog-to-digital conversions of a measurement m of the series, m being a natural integer comprised between 2 and N, is defined as being equal to the reference period plus the product of (m−1) and a predetermined additional unitary period, wherein the additional unitary period is equal to half the period needed to shift a noise peak, that is to say a noise sensitivity peak associated with the sensor, by half its frequency width.