How does the Rain Sensor sense the change of wind and rain?
Publish Time: 2024-09-09
The process of the Rain Sensor sensing the change of wind and rain is mainly based on optical principles, combined with electrical processing to achieve accurate judgment and control of rainfall conditions.1. Overview of working principleThe Rain Sensor is a relative measurement device, and its working principle is based on the reflection of light on the windshield. The sensor contains a transmitting tube (usually an infrared transmitter) and a receiving tube (photoelectric receiver), as well as related optical components and electrical processing units.2. Perception processInitialization stage:When the surface of the windshield is dry, the light emitted by the transmitting tube (such as infrared light) is incident on the windshield in parallel and is reflected back almost 100%.The reflected light is gathered by the optical element and received by the receiving tube. At this time, the sensor will be initialized, record and store the received light intensity under the condition of fixed emission current.Raindrop perception stage:When there are raindrops on the outer surface of the windshield, the light incident on the windshield will be partially scattered, resulting in a decrease in the light received by the receiving tube after reflection.As the amount of rainfall increases, the scattering effect of raindrops on light increases, and the light reflected back to the receiving tube further decreases.Data processing and judgment:The electrical processing unit inside the sensor processes the received light intensity signal, and calculates the change in the current reflected light intensity by comparing the light intensity received when the windshield is dry.According to the change in the reflected light intensity, the sensor can determine the size and number of water droplets on the windshield, and then identify different rain patterns (such as light rain, moderate rain, heavy rain, etc.).3. Wiper controlWhen the system detects raindrops and determines the rain pattern, it will send a wiper request to the vehicle's BCM (body controller) or independent controller.The controller controls the wiper to complete intermittent wiping, low-speed continuous wiping, or high-speed continuous wiping according to the received request signal and the preset algorithm to adapt to different rainfall conditions.The Rain Sensor senses the changes in wind and rain by emitting light through the transmitting tube and sensing the changes in the reflected light intensity on the windshield. When there are raindrops on the windshield, the reflected light is reduced, and the sensor determines the rain pattern through data processing and controls the wipers to perform the corresponding wiping action. This process realizes the precise perception and automatic control of rainfall conditions, improving driving safety and driving comfort.
