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 to detect whether or not a human is present in proximity to the sensor, each of the measurements comprising an alternation of a first acquisition phase and a second acquisition phase over a constant period, said first acquisition phase comprising 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 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 configured to perform measurements in a repetitive being predetermined sequence, said sequence comprising a series of N consecutive measurements, N being a natural integer greater than or equal to three,
• wherein a reference period is defined as being between two consecutive analog-to-digital conversions of the first measurement of the series, another 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, the additional unitary period being equal to half a period needed to shift a noise sensitivity peak associated with the sensor.