Rain sensor is an advanced driver-assistance system that detects water on a car’s windscreen and automatically triggers programmed actions. The main function of this system is activating windscreen wipers in the rain. But the triggered actions might also include closing the car’s windows and sunroof.
How does it work? The rain sensor is located behind the windscreen near the rearview mirror. It consists of LEDs that beam infrared light and a central photodiode that measures the amount of light that lands on it. The infrared light is beamed on the windscreen at a 45-degree angle where it reflects back onto the photodiode. When the windscreen is dry, all of the light is reflected. The more drops of water there are on the windscreen, the less light the photodiode receives. This information is sent to an electronic control unit which turns on the wipers and adjusts their speed accordingly.
The purpose of rain sensors is to make driving in wet conditions safer and more comfortable. The driver does not have to shift their focus off the road to turn on the wipers or close the windows. The system does it for them and they can focus on the road. Since the automated system can react faster than a human, it is especially important in situations where the driver may experience sudden visual distractions, for example in the case of a thunderstorm.
Synonym(s):
- Windshield rain sensor
- Windscreen rain sensor
- Rain-sensing wipers
