Method and device for presence detection for a motor vehicle

A device for detecting human presence close to a motor vehicle, said device comprising:

• a detection sensor able to provide a presence-detection analog voltage signal,
• a converter able to convert said analog voltage signal into at least one coded digital value and
• a microcontroller able to receive said coded digital value,
• said converter being characterized by its predetermined finite number of successive coded digital values corresponding to a series of successive intervals of values of the analog voltage signal, the length of said series of consecutive intervals corresponding to a reference value of the converter and
• the microcontroller being able to apply a plurality of different reference voltage values to the converter and
• the converter being configured so as to convert, at said plurality of values of the reference voltage, an analog voltage signal provided by the sensor into a plurality of coded digital values, said consecutive intervals of values of the analog voltage signal of the converter being characterized by a maximum width, the absolute difference between two values of the reference voltage being greater than said maximum width,
• the microcontroller furthermore being configured so as to:
• correlate said coded digital values in order to obtain a correlation value,
• compare the obtained correlation value with a predetermined reference value, and
• detect human presence close to the sensor when the difference between the obtained correlation value and the predetermined reference value is greater than a predetermined detection threshold,
• wherein, with the sensor comprising a reference capacitor and a storage capacitor, the microcontroller is able to command the conversion of the analog voltage signal into a coded digital value between charging of the storage capacitor and complete discharging of the storage capacitor.