Rain sensor can estimate falls within a certain time on the windscreen amount of rain, the automatic wiper system under the rain sensor signal determines the desired wiper interval. This device consists of a transmitter diode and a receiver. When the weather is dry, there is always a beam of light from one sensor to another sensor (beam propagation rate of 100%). If the glass is wet (beam propagation rate of less than one hundred percent), the direction of the beam shift occurs, the offset is proportional to the extent and amount of rain. Its working principle is to reach the receiver, the less light, blowing rain faster. It should be noted that, when you remove the ignition key after, to system recovery. When the wipers when the duration (seven forth above), rain detector will automatically light up headlights (based models may be) advantages: to improve active safety and driving comfort. Rain sensor wiper control system according to the intensity of the rain wiper automatically adjusts wiper speed, to the greatest extent your driving convenience. Are free to adjust the height and angle of the steering wheel allow you to create the most appropriate for their driving environment, though not the four-spoke steering wheel, but the three spokes is more suitable for sports.
According to the  Throttle Body  Kero noted, if the car has a rain sensor, motorists do not need to adjust the settings to quickly stop the wiper blade movement or to get a better perspective. When driving on wet roads, motorists do not need hands to open the wiper, so the driver can concentrate on driving. If you installed additional "auxiliary light switch," lights will dim timeout conditions in open and not be wasted fuel has been driving lights. Most models are used in a single-motor-driven wiper system. The advantage of this system is self-evident, the use of the wiper linkage mechanism drive 2, the cost is relatively low. However, noise and rain and snow wiper wiper without a net phenomenon still occur.
Most of the rain sensor with the optical system having a light-emitting diode (LED), a light receiving diode (LRD), the surrounding environment sensor, electronic control unit (ECU) and several lens components.
The light emitted by the LED to the total reflection angle of the outer surface of the windshield reflections, the angle must be 420 (glass - air) and 630 (glass - water) between. If upstream of the windshield, said some of the light will be emitted twice, and this would cause the current reduction from LRD out, the current to the evaluation electronic, reflecting the light emitted from the LED to the windshield area is LRD
Called the sensor's "sensitive areas." Only when the rain dripping this area, we can be detected. In order consists of a sensitive and reliable system, windshield between regions and sensitive area must have a good ratio.
Windshield wiper system consists rain sensor wiper motor, pole switches, relays and the ECU components. Rain sensor is mounted on the windshield in the rain sweeping area detection when the wiper to a way for motorists to always have a good perspective to exercise. There are two different systems.
The transmitter consists of analog - digital converter (DAC) and power supply. DAC's analog voltage of the LED control determines the intensity of the light emitted, in general, the use of two to four LED. Emitter current regulation is important because the effectiveness of light conversion is available and there is a temperature gradient becomes. In general, the LED, the light emission in pulsating manner to reduce losses and increase the current. Using a wide range of the transmitter current, another reason is the emission of light through the windshield is not very good and there is a lot of specification tolerance range. Windshield generally has 4 ~ 6mm thick and perpendicular to the surface of the IR emitted by a specific level. Different suppliers of different upper and lower limits.
The receiver has several LRD, current - voltage converter, clear or low frequency offset of filters, amplifiers and ADC, which typically also includes a microcontroller. LRD a microcontroller is controlled by a micro-controller on and off. If
According to the   Throttle Body    Kero understood, the presence of interference light, LRD is turned off. The wide range is transmitted using a variable current - voltage converter to ensure that the receiver has a good rest of the system causes of the condition. After conversion, but fortunately was filtered. All DC or low-frequency interference will be removed to obtain a pure signal. Interference generally caused by light from the surrounding environment, the amount of interference with a micro-controller to measure to determine the optical path is satisfactory, or saturated by sunlight, and will give an indication signal accuracy. The filtered signal is amplified by the ADC conversion.