Patent ID: 7830267

Claim:
A rain sensor for a vehicle, comprising: a printed circuit board (PCB) to be supported by a vehicle window, the PCB comprising first and second outer layers and at least one inner layer, the first outer layer adapted to be closest to an interior of the vehicle and the second outer layer adapted to be closest to an exterior of the vehicle; first and second capacitor arrays, the first capacitor array being formed on an outer surface of the first outer layer of the PCB and the second capacitor array being formed on an outer surface of the second outer layer of the PCB, one or more sensing capacitors in at least one of the first and second capacitor arrays being sensitive to moisture on an external surface of the window; and programmed logic circuitry configured to distinguish between at least moisture on the exterior surface of the vehicle window, humidity on the interior surface of the vehicle window, and EMI, wherein the at least one inner layer is arranged so as to decouple the first and second capacitor arrays and to shield the first capacitor array from fields emanating from the second capacitor array, and vice versa, and wherein EMI is detected when the first and second capacitor arrays detect identical or similar signals substantially simultaneously.