AUTOMATIC WATER PUMP CONTROLLER
The automatic water pump controller is used to control the water pump motor. The motor gets automatically switched on when water in the overhead tank (OHT) falls below the lower limit. Similarly, it gets switched off when the tank is filled up. Built around only one NAND gate IC (CD4011), the circuit is simple, compact and economical. It works off a 12V DC power supply and consumes very little power. The circuit can be divided into two parts: controller circuit and indicator circuit. The controller circuit is one which is used for the purpose of controlling the water pump action. When the water level reaches a maximum level the motor turns off and when the water level goes below the minimum level the motor turns on automatically.
This circuit consists of a NAND gate IC (4011), three transistors (BC547), two relays with specification 12V, 200ohm 1C/O, four resistors (1K), two diodes (1N4001). The indicator circuit is one which is used to indicate the level of water inside the tank. Depending upon the number of LEDs that glow we can determine the level of water inside the tank. This circuit consists of five LEDs, five NPN transistors (BC547), ten resistors (1K). So, from the glowing of LEDs, one can determine the water level in the tank. This device is very much useful to curb the overflow of water in overhead tanks which in turn favours conservation of water. With further advancements, it can be used to check the level of water in dams.