Rain Sensor Working and Its Applications

Nowadays, conserving water as well as its proper usage is essential in everyone’s life. Here is a sensor namely rain sensor which is used to detect the rain and generate an alarm. So, we can conserve water to use it later for different purposes. There are several methods available for conserving water like harvesting, etc Using this method we can increase the level of underground water. These sensors are mainly used in the field like automation, irrigation, automobiles, communication, etc. This article discusses a simple as well as reliable sensor module which can be available at low cost in the market.

What is a Rain Sensor?

A rain sensor is one kind of switching device which is used to detect the rainfall. It works like a switch and the working principle of this sensor is, whenever there is rain, the switch will be normally closed.

Rain Sensor Module

The rain sensor module/board is shown below. Basically, this board includes nickel coated lines and it works on the resistance principle. This sensor module permits to gauge moisture through analog output pins & it gives a digital output while moisture threshold surpasses.


This module is similar to the LM393 IC because it includes the electronic module as well as a PCB. Here PCB is used to collect the raindrops. When the rain falls on the board, then it creates a parallel resistance path to calculate through the operational amplifier.

This sensor is a resistive dipole, and based on the moisture only it shows the resistance. For example, it shows more resistance when it is dry and shows less resistance when it is wet.

Pin Configuration

The pin configuration of this sensor is shown below. This sensor includes four pins which include the following.

  • Pin1 (VCC): It is a 5V DC pin
  • Pin2 (GND): it is a GND (ground) pin
  • Pin3 (DO): It is a low/ high output pin
  • Pin4 (AO): It is an analog output pin


The specifications of the rain sensor include the following.

  • This sensor module uses good quality of double-sided material.
  • Anti-conductivity & oxidation with long time use
  • The area of this sensor includes 5cm x 4cm and can be built with a nickel plate on the side
  • The sensitivity can be adjusted by a potentiometer
  • The required voltage is 5V
  • The size of the small PCB is 3.2cm x 1.4cm
  • For easy installation, it uses bolt holes
  • It uses an LM393 comparator with wide voltage
  • The output of the comparator is a clean waveform and driving capacity is above 15mA


The applications of rain sensor include the following.

  • This sensor is used as a water preservation device and this is connected to the irrigation system to shut down the system in the event of rainfall.
  • This sensor is used to guard the internal parts of an automobile against the rainfall as well as to support the regular windscreen wiper’s mode.
  • This sensor is used in specialized satellite communications aerials for activating a rain blower over the opening of the aerial feed, to get rid of water droplets from the mylar wrap to keep pressurized as well as dry air within the waveguides.

Thus, this is all about the rain sensor. From the above information finally, we can conclude that this sensor is used to detect the rain and generate buzzer sound to take necessary action in further. Here is a question for you, what is the function of LM393 comparator?