In this tutorial, we are making a project on an Automatic rain-sensing windshield wiper control circuit. Usually these days some modern vehicles use optical-based rain sensors for controlling the wiper system but if your car won’t have that system you can easily make one by yourself through this tutorial. This circuit is not using any optical technology but is a very versatile and inexpensive component.
It is using the famous NE555 timer IC that has three modes of operation i.e., astable, monostable, and bistable. Here it is working as a monostable multivibrator.
Hardware Components
The following components are required to make an Automatic Rain Sensing Circuit
| S.no | Component | Value | Quantity |
|---|---|---|---|
| 1. | DC Supply | 12V | |
| 2. | Sensor | – | 1 |
| 3. | Resistor | 1M | 1 |
| 4. | Ceramic Capacitor | 1nF | 1 |
| 5. | Electrolytic Capacitor | 10µF | 1 |
| 6. | IC | NE555 Timer | 1 |
| 7. | Relay | 12V | 1 |
| 8. | Diode | 1N4007 | 1 |
NE555 IC Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 Timer
Automatic Rain Sensing Circuit
Working Explanation
The operating voltage of this circuit is 12 volts DC. When two-wire in the hand-made sensor will detect raindrops then the output of the 555 IC at the output pin 3 will become high and activates the relay for a specific period of time. After that time period, pin 3 will become low and the relay will switch off again. The activation time period depends on the values of the resistor and capacitor used at the input pins of the IC, it can be increased by increasing the value of the capacitor Cx.
After the circuit is built connecting the switch or wires of the wiper motor with the relay. Connect long wires with the sensor. Set this sensor at the corner of your car’s windshield glass or someplace where it gets direct rain so that the sensor can sense. Make sure the sensor should be set in 90 degrees direction or in the direction of your windshield glass so the raindrops will slip over from the plastic sheet. This will save from triggering the relay when the rain stops.
Applications and Uses
- Automobiles
- Windows
- Glass Doors, etc.
