Simple Rain detector alarm circuit

Last Updated on March 16, 2024

Single transistor Rain detector alarm or water drop detector alarm, We can use this circuit any way. This construction works under the principle of “transistor switch” when we giving voltage at the base terminal the transistor starts the conduction. When we remove the supply from base transistor goes to cutoff condition.

By using this character simple rain detector circuit made. By connecting buzzer series to the (npn) transistor we can get alarm circuit. The sensitivity range of this circuit varies with respect to the R1 resistor.

rain detector alarm

Handmade Rain Sensor


By using single stand wire and dotmatrix board we can make simple rain sensor, while making this sensor take two piece of wire remove the sleeve and stitch the metal into dotmatrix board without touching pair wire as mentioned in the circuit diagram.

Components List

S.No Name Quantity
1. Transistor – SL100 1
2. Buzzer 9V 1
3. Resistor 100Ω 1


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