Method for detecting a user's intention to lock or unlock a motor vehicle door and associated device

A device for detecting the intention of a user to lock or unlock a motor-vehicle door, said device being integrated into a handle and powered by a voltage source, the device comprising:

• a coil,
• a movable electrode a first face of which is oriented toward the handle, and a second face of which is located facing the coil, said movable electrode being able to move from a rest position, located in proximity to the handle, to a final position, located in proximity to the coil under the effect of a contact of the user on the handle,
• a capacitor connected to ground, the movable electrode, the coil and the capacitor being connected together in order to form a resonant circuit a resonant frequency of which varies as a function of a variation in the capacitance of the movable electrode, and of the position of the movable electrode, said resonant frequency decreasing when the user approaches the handle and increasing when the user grips the handle and the electrode moves to the final position,
• means for oscillating the frequency of said resonant circuit and means for measuring a resonant frequency of said resonant circuit,
• means for comparing the resonant frequency to a first threshold and to a second threshold,
• means for controlling the frequency-oscillating means, the measuring means and the frequency-comparing means,
• a clock,
• means for storing times in memory, said means being able to store a first time of passage of the resonant frequency below a first threshold and a second time of passage of the resonant frequency above a second threshold,
• means for computing a duration between the first time and the second time, and
• means for comparing said duration with a preset duration).