Rain Sensor

Detecting the first raindrops or moisture on the windshield and adjusting wiper speed to match the rainfall level has become a typical feature in today's luxury vehicle. At the 2005 Frankfurt Auto Show, Hella announced a capacitive rain sensor design for integration into the windshield similar to a radio antenna. The barely visible unit allows areas of the windshield or rear window to be used for rain detection that previously had been difficult to sense. This occurs in contra-rotating wiping systems, which use the butterfly principle, and panorama windshields. The rain sensor is a capacitor which changes value depending on the amount of water hitting the windshield. Rain drops hitting the sensor area of the windshield detune an electric oscillator circuit containing the capacitive sensor and cause a signal change proportional to the amount of water. This input controls the wiping intensity providing a level of functionality beyond intermittent wipers. For more information on Hella's capacitive rain sensor go to: http://rbi.ims.ca/4914-500