Patent ID: 7319301

Claim:
A proximity sensor mountable adjacent to an aperture of a metallic motor vehicle for determining the presence of an object in the path of or proximate to a closure panel that moves between a fully open position and a closed position, the sensor comprising: first and second electrodes encased in a non-conductive casing mountable on the vehicle, the two electrodes defining a capacitance CE 1 / 2 therebetween; a reference capacitor (C 1 ); a first switch for selectively connecting the first electrode to the reference capacitor or to chassis ground; a second switch for selectively connecting the second electrode to a first voltage reference source (V ref1 ) or to chassis ground; a controller for controlling the first and second switches in order to periodically charge the capacitance CE 1 / 2 and transfer the charge stored thereon to the reference capacitor.