Rain sensors: what is it?

Many models of modern cars are equipped with rain sensors. What it is? What are they needed for? Is this the right thing, or just another marketing ploy? Let's figure it out.

Why is this needed?

Bad weather is a direct threat to ride comfort, driver health and vehicle integrity. If ice, slush and snow are the concerns of the respective services, then the owner should deal with the pollution of the windshield, and as soon as possible. Previously, the driver had to perform additional actions.

In the seconds spent turning the cleaning brushes on and off, anything could happen. In addition, a person will not be able to react quickly enough to the water that fills the glass. Another thing is the rain sensor, which will perform this task for you. An automated system will detect the presence of drops on the glass, and, depending on the degree of contamination, will start the desired cleaning mode. Let's take a closer look at how this works.

How does a rain sensor work?

Let us consider in more detail what this is. The rain sensor consists of two LEDs: emitting and receiving. One emits infrared rays, and the other (sensor) captures their refraction. The basis of the work is the principle of comparing clean and dirty glass. What does it mean? That is, the refractive indices of the rays on clean and dirty glass are loaded into the memory of the electronic device. If the glass is detected as wet, a cleaning system is started. How is this happening? Depending on the amount of precipitation, a suitable purification rate is selected. In modern cars, there can be up to 7 different modes. When the glass is cleaned, the wipers will turn off automatically.

Device

The rain sensor consists of two parts connected by a wire:

1. A control unit that issues commands to the actuator. This is where the infrared LEDs are located. It must be placed on the inside of the windshield so that it does not obstruct the driver's view. At the same time, it should be in the work area of ​​the wipers. Usually it is mounted behind the rear view mirror.
2. The relay block, which turns the cleaning system on and off, and also protects the sensor from voltage surges and conducted noise. It is installed in a place convenient for connecting to the mains.

The whole device does not take up much space and is compactly located in the cabin.

Advantages and disadvantages

Advantages of the rain sensor:

1. The driver does not need to be distracted from the road to turn on and off the wipers.
2. Quick response to glass contamination.
3. Rain sensors have been produced since the 2000s, and all this time only middle-class cars and above were sold with them. Now the rain sensor has ceased to be a privilege of expensive cars. It can be installed in budget models.
4. It is believed that a windshield with a rain sensor cannot be tinted. But this problem was found to be solved: manufacturers make tint films with a hole for the rain sensor. And in general, tinting the windshield is not a good idea.
5. There is another common misconception - that the rain sensor will not work at night. It is not true. For infrared rays, the time of day and the degree of illumination on the street are not important.

Like any device, the rain sensor has disadvantages:

1. The windshield must be intact and not deformed. Otherwise, the sensor will not work.
2. Does not recognize snowflakes on glass until they melt.
3. Excessive sensitivity. The sensor can trigger from one random drop of water.
4. If water does not fall into the coverage area of ​​the wipers, the sensor will not work.
5. Only the wipers are turned on, but the washing system is not. If dirt gets on the glass, it will simply smear.

This article describes the pros and cons of a unique device. It's up to you to decide whether the rain sensor is not just a marketing ploy, but a really useful thing.