sensor wipers by rain sensor for sensing the size of raindrops, the wiper speed automatic adjustment, to provide good visibility for the driver, thus greatly improving the convenience and safety of driving rain.
1. The sensing wipers noun
sensor wipers rain sensor by sensing the size of raindrops, the wiper speed automatic adjustment, to provide good visibility for the driver, thus greatly improving rain convenience and driving safety.
2. The sensing wipers works
Currently the widely used two mainstream sensors are optical sensors and capacitive sensors.
● optical sensor
The optical sensor is a principle of light refraction. In the optical sensor has a light emitting diode, which emits a cone of light, which beam passes through the front windshield. When there is no rain on the windshield, in a dry state, almost all the light will be reflected onto an optical sensor, when it rains, rain on the windshield will be there, will deviate from the portion of the light, which resulted in change the total amount of light received by the sensor, thereby detecting the presence of rain. The larger the optical sensor capable of receiving the reflected light area, more detailed information is obtained. An optical sensor is very accurate, it is possible to accurately determine even the number of the rain falling on the sensitive region.
● capacitive sensor
Another is a capacitive sensor, which is mainly used in the dielectric constant of water glass and a huge difference design, wherein the dielectric constant of water is 80, the dielectric constant of glass is 2. The usual practice is, the two fingers in a parallel state of the metal plate into the windshield, between the outer layers, a set of metal plates interleaved with fingers, but does not reach the other electrode fingers metal board. When the windshield in a dry state, the outer surface of the windshield and each finger is formed between the dielectric plate-like metal. When the windshield becomes wet, depending on the amount of water in contact with the windshield, the windshield different dielectric constant change. If the sensor is mounted on the surface of the windshield at or close to the surface of the windshield, which is advantageous for the operation of the sensor, since such mounting can play their best sensor sensitivity. Disadvantageously, the capacitive sensor mounted on the outer surface of the windshield will have the same problem with a sensor resistance which the metal plating layer will soon be scraped from the windshield wipers in the long-term.