Rainfall Detector Alarm using 555 Timer & Rain Sensor
555 Timer Project – Rainfall Detector Alarm using 555 Timer & Rain Sensor is a mini electronics project for Electronics Students.
The main component of this rain alarm is the rain sensor. Whenever the raindrop would fall on the rain sensor, it will short the point A and B, and a voltage would get applied to the base of the Transistor, and it will become ON.
It is a very simple rain alarm circuit that is designed using mainly a transistor, water sensor, and a 555 timer IC.
Circuit Diagram
The components required for designing a Rainfall Detector Alarm using 555 Timer & Rain Sensor are as follows:
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1 2 3 4 5 6 7 |
1. 555 timer IC 2. Rain Sensor (You can design by yourself) 3. Transistor - BC147 (any NPN transistor) 4. Buzzer 5. Capacitors - 10uF 6. Resistors - 470E, 1K, 4.7K, 100K (2 nos) 7. 9 Volt Battery |
The Circuit diagram of the project is given below. Assemble the circuit as shown in the circuit diagram.
Working of the Circuit
Whenever there is rain, raindrops fall on the rain sensor, and as you can see in the diagram of a rain sensor, water on the rain sensor would short the Point A and B. As soon as Point A and B become short, a positive voltage would get applied on the base of Transistor Q1, through the resistance R4. Because of the voltage at the base, the transistor becomes ON (initially it was in an OFF state), and currently started flowing form the collector to the emitter.
Now Reset PIN 4 of the 555 Timer, gets a positive voltage and 555 timer IC becomes ON and Buzzer starts beeping. Here we should note that initially there was no positive voltage at Reset PIN 4 of 555 IC, as it was connected to the ground through resistance 4.7k and 555 IC only works when the Reset pin gets positive voltage. Here we can see that 555 Timer IC has been configured in Astable mode so that Buzzer generates an oscillating sound (means periodically on and off).
Video Demonstration
