Rain Alarm

We are a prominent name offering efficient Rain Alarm. Based on advanced technology, Rain Alarm alerts the people when it begins to rain. The circuit of Rain Alarm is built around monostable multi vibrator IC1. The sensor connected to trigger pin2 of IC1, is made from resistor leads or small metal foil pieces. When sensor detects rain, IC1 gets triggered and raises the alarm. In addition, when the rain stops, the circuit switches off automatically. Our esteemed customers can avail Rain Alarm at economical price.
About the Circuit :

• The circuit is based on the operation of IC1. It is used in the monostable mode i.e. it gets triggered when the voltage at pin2 is below 1/3Vcc.
• When rain falls on the sensor, the voltage at pin2 goes below 1/3Vcc. Hence, IC1 generates high output pulse at pin3. As a result, transistor T1 connected to pin3 conducts and piezobuzzer connected to it sounds an alarm. LED D1 gives the visual indication that the rain falls.

Note on Sensor :
One can make a suitable sensor according to one’s choice. A model of the sensor is shown in figure. The distance between the rails is made as small as possible so as to have a more compact and reliable sensor.