Rain sensor, function - GF82.30-P-4103-02R
Functional principle
Infrared light is radiated from the infrared transmitter (2) through the lens (1) to the windshield (4). The intensity of the light reflected at the windshield (4) is measured by the infrared receiver unit (3) that is located at the other end of the lens (1)
If the windshield (4) is dry in the reflection area (figure A), almost all of the light is reflected and the infrared receiver unit (3) measures a high degree of light intensity.
If the windshield (4) is wet in the reflection area (figure B), some of the light is diffused out of the glass of the windshield (4). This reduces the intensity of the reflected light, and the infrared receiver unit (3) measures a lower light intensity.
The light intensity measured by the infrared receiver unit(3) is a measure for the degree of wetness of the windshield (4). The lower the measured intensity, the greater the degree of wetness of the windshield (4).
The information is transmitted on the Controller Area Network bus class B (interior) (CAN-B) via the overhead control panel control unit.