10-04-2017, 08:31 PM
Rain alarm is an application which detects the rain water and blows alarm. They are useful devices and play an important role in various industries such as automobile, irrigation, and wireless communication. Desiging a rain alarm system is quite simple and we have designed here a demo rain alarm project with the help of 555 Timer IC.
Components
Rain sensor (Either you can purchase or build yourself)
555 Timer IC
NPN Transistor BC547
Resistors (470, 100k and 1k ohm)
Capacitor (10uf)
Buzzer
Battery 9v
The main component of this rain alarm is rain sensor, I have purchased one, but we can also build it at home. It s very easy to create a rain sensor. Take a sheet of Bakelite or mica, and paste the aluminium wire on it according to the diagram shown below. The Gap between the wires should be around 3-5mm. You can see that whenever the rain drop would fall on rain sensor, it will short the point A and B and a voltage would get applied on the base of Transistor, and it will become ON. We can also use copper wire for rain sensor but copper generally reacts to oxygen to form oxide, so it needs to be cleaned on regular basis.