A rain sensor alarm circuit can be a very beneficial device for alerting when rainfall happens. The rain detector circuit shown here is very simple using only three components but is very sensitive to detect rain or moisture. The sensor part of the circuit can be easily made with verobaord or you can also make it in
home by attaching thin metal strips on plastic or wood etc. The sensor can be made by several techniques, and performance of the circuit is also depends on the sensor. For better performance make sure to give no more than 1minimeter gap between the sensor strips.
Working of the Circuit:
Working of the circuit is simple the transistor BC547B is working as a switch in this circuit when the water droplets fall on the sensor the transistor will become switched on and the 9V will start passing through the transistor which will activate the Buzzer.