Patent ID: 8576083

Claim:
A rain detector used in conjunction with a windshield with an inside and an outside surface comprising: a capacitance sensor adapted for attachment to the inside surface of the windshield, said sensor having at least two output lines which vary in capacitance as a function of the magnitude of rain on the outside surface of the windshield aligned with the sensor, a programmed microcontroller which receives the magnitude of the capacitance on the sensor output lines as input signals and generates an output signal which varies in frequency in an amount proportional to the magnitude of capacitance on the sensor output lines, an RC network electrically connected to said microcontroller, said variable frequency output signal connected as an input signal to said RC network for a predetermined time period, said microcontroller being programmed to determine a voltage on said RC network at the end of said predetermined time period and to generate a wiper activation output signal only whenever said voltage exceeds a predetermined threshold, and a wiper control circuit which receives the microcontroller wiper activation output signal as an input signal, said wiper control circuit activating at least one wiper for the windshield in response to said wiper activation signal.