How Does a Windshield Rain Sensor Work?

There are comfort options on a vehicle that you get used to quickly: the auto rain sensor is one of them. This equipment is used to provide better control of the vehicle’s wipers, depending on the density of the rain. It facilitates driving in rainy weather since it allows you to focus your attention on the road.

The rain sensor makes it possible to perfectly control the operation of the wipers. Typically, the operating intermittent setting should be constantly adapted to the density of the rain, and wipers are often left on for a long time after the end of the rain.

Automatic wiping overcomes these problems, it allows you to:

• start the wiper function automatically;
• adapt the wiping speed to atmospheric conditions;
• associate other functions such as automatic closing of openings (roof, electric windows, etc.).

Advantages of the auto rain sensor.

The detector allows you to focus your attention on driving the vehicle. It is very reactive (0.1 sec reaction time) and can detect sudden splashes from other vehicles. Overall, it improves your comfort and driving safety.

The rain detector system is composed of the following elements:

• A calculator that manages the wiping system. It is he who adapts the rate of wiping according to the density of the rain and possibly controls other auxiliary functions, such as closing openings or lighting.
• A rain sensor positioned on the windshield in the pedestal of the mirror
• The sensor, according to the intensity of the rain, sends a variable electrical signal to the computer. It then proportionally controls the wiping and its scanning speed.

The infrared sensor

It is composed of two diodes, one transmitting an infrared ray and the other receiving. The beam is diffused in the glass of the windshield and in dry weather, reflected by the walls to the receiving diode: the system is passive. In rainy weather, drops of water on the surface of the windshield deflect the light beam and absorb it: the photodiode is no longer supplied, the system triggers the wiping. This sensor is sensitive to light and allows the “automatic lighting” function: it can automatically switch on the headlights in case of loss of light: night, tunnel, etc.

The ultrasonic sensor

This variant uses ultrasound technology. The principle is similar, but it is not sensitive to light. It does not allow the automatic lighting function. Good to know: infra-red and ultrasound are both undetectable for the human senses, they will not interfere with your behavior.

Original equipment

With the purchase of the new vehicle, the “automatic wiping” option is now offered by all brands. The extra cost is estimated by the builders from 150 to 300 dollars.

Adaptation of a kit “auto rain detector”

It is possible to fit a kit on your vehicle. This product offers most of the time the two cumulative functions “automatic wiping” and “automatic lighting”. The price of a kit to the adaptation varies from 70 to 90 dollars.