1
what’s the use?
When it rains, without having to open the driver’s manual operation of the wiper, the wiper may be turned on automatically.
2
[ 123] advantages:
· hr rainfall suddenly large repeatedly without driver’s manual adjustment of the wiper switch, which automatically adjusts the oscillation frequency of the wiper according to the size of rainfall. After the rain stopped, wipers automatically shut down, eliminating the need for manual operation, ensure safe driving rain.
3
Error:
· rainfall sensors detect hidden behind the front windscreen, rainwater coverage and only covers the speed of the front windshield is detected, acquisition and analysis were not weather outside the vehicle.
· wiper frequency stepless adjustment, the slower the fade rainfall rainfall bigger and faster. And several fixed gear speed is not the same common wiper.
4
Principle:
Currently the widely used two mainstream sensors are optical sensors and capacitive sensors. The optical sensor works according to the 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.
Another is a capacitive sensor, which is mainly used in the dielectric constant of water glass and a huge difference in design, wherein the dielectric constant of water is 80, the glass a dielectric constant of 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.
5
reading:
For some models integrated skylight window function and the sensing function wiper control, once the glass is covered with a quantity of water, the sensor orders immediately on windows and skylights, windows and the sunroof will automatically turn off immediately.