Automatic Rain Sensing Wiper System using 555 Timer

Have you seen Audi, Lexus or Ford rain sensing wipers and wondered how they work in these vehicles? They are handled by sensors at the center of the windscreen which detects rain water and turns on the wiper motor. Here is the working of rain sensitive wipers with circuit schematic. The main component of this circuit is a 555 timer IC that works in monostable mode. Two metal sheets fixed at a small distance apart are used as rain detector sensors. From the working of a monostable 555 timer, a negative voltage on the trigger pin will cause a high output. So when it rains, trigger pin gets a negative voltage. Output of one shot 555 (monostable) is connected to a relay through a transistor. The transistor acts as a switch for the relay to turn ON the wiper motor during rain.

Circuit diagram

rain sensing wiper schematic

Components required

  1. IC 555
  2. Transistor BC 548
  3. Diode (1N4007)
  4. Resistor (1K,10K,1M,)
  5. Capacitor(0.1uF)
  6. Relay (12V,10A)
  7. Rain sensor (Two metal sheets as figure)

How rain sensing wipers work?

Working of this circuit is same as the working principle of monostable multivibrator. Here the trigger to the second pin is given by rain sensors.

A small water drop on the rain sensor will connect the negative voltage to the trigger pin of 555 IC which in turn will turn the output pin of 555 high. 5

55 Output is connected to the base of transistor through a 1K resistor which forward biases the transistor. Thus relay gets negative and it switches ON the wiper motor. You can refer our previous post on how relay works for better understanding of relay.

Components Pin out

47 thoughts on “Automatic Rain Sensing Wiper System using 555 Timer

    • Hi Girish
      1. You modify with connecting more circuits with this.
      2. You can use Micro controllers for this, which helps you to control the speed of wiper arm depend on the rain.

  1. I want all the materials of Automatic Rain Sensing Wiper Using micro-Controller including circuit diagram, connection , code.
    please, send me as soon as possible.

  2. hi,
    I am currently doing a minor project on Automatic rain operated wiper with respect to rain intensity.My Objective is to automatically controll the speed of wiper motor with the help of Grid rain sensor and Microcontroller.
    I have purchased a RAIN DROP SENSOR Module KG004. I am not able to find a ideal circuit diagram for this project.
    Please help me in executing this project.

    With Regards


  3. Does the sensor only consists of metal screws mounted on non-conducting material or is there a circuit further to complete the sensor?…. Thank you

  4. hello and i want a video how to do this micro project in this experiment i want a clear video of this experiment so plse keep video of this

  5. there are some rain sensors available for arduino and other MCUs.
    Can we use them in this circuit ?
    please specify a rain sensor you prefer .

  6. sir, pls send me the final report of automatic rain sensing wiper as i have seletected it as a mini project in colg

  7. hye, I have connected such like in the diagram. but it doesn’t work. The motor still be run eventhough i have turn off the switch. and there have no current for connection to the ground. can u explain me ?

  8. Hye yassen, i have already set up the connection like in the diagram. And the rain sensor i change it with the switch in simulation. But, when i run the simulation in proteus 7, the motor still work out even though i turn of the switch and also there have no current at the connection wire to the ground. So, can u explain me ?

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