Design and Construction of Automatic Level Controller Circuit with 555 Timer IC

ABSTRACT

Automatic water level controller circuit automatically switches ON and OFF a domestic water pump set depending on the tank water level. This motor driver circuit can be used at home, industry, school or even in agriculture. The approximated cost of the project is very less. The main advantage of this water level controller circuit is that it automatically controls the water pump without any user interaction. The main controller component is a NE 555 IC. We have manipulated the flip flop inside the 555 timer IC to operate as bi-stable multivibrator. The project consists of three water level sensors, one fixed at the top and the other at the bottom.  A Simulation of the power circuit was carried out using Proteus software to generate 12V dc supply for powering the relay. Whenever the trigger pin (pin 2) of the 555 timer sees a 0v showing that the water level is close to the bottom of the tank, the output pin (pin3)generates a high pulse which biases an NPN transistor. Current now flows through the relay through the collector then to ground. This current energizes the relay and the NO contact changes to NC thereby supplying power to the water pump to refill the tank. The different water levels inside the tank could be viewed at all times from the LED display that is calibrated according to the tank levels.