Automatic Water Level Controller Project Using 555 timer Ic For Overhead Tank

Here is a simple water level controller project using the 555 timer ic which will monitor the overhead tank. It will automatically switch on the motor when the level of water falls below the predetermined bottom level and switches off the motor when it reaches the pre-set top level.
The levels in the overhead tank are sensed by metal electrodes or float switches mounted inside the tank.
Let us consider the situation when the overhead tank is empty and there is no connection between the three electrodes. Since the sensor “Bottom” is open, the potential at the pin 2 is drawn towards the ground. This will trigger the lower comparator to signal the flip-flop to go low and the output at pin 3 goes high. This activates the relay through the transistor Q1 and the motor starts working.

When the water level reaches the upper sensor “Top”, it will trigger the flip flop to go to a high state and consequently the output at pin 3 goes low. This deactivates the relay and the motor stops working thus preventing the water wastage. This circuit can be tested on a breadboard and easily assembled on a general purpose PCB.