Automatic water tank level controller motor driver circuit- Engineering project without Microcontroller

Automatic water level controller circuit is a simple engineering project. It can automatically switch ON and OFF the domestic water pump set depending on the tank water level. You can implement this motor driver circuit at your home or college using less costly components. The approximated cost of the project is about $5 only. The main advantage of this water level controller circuit is that it automatically controls the water pump without any user interaction.
The heart of this pump controller circuit is a NE 555 IC; Here we have manipulated the flip flop inside the 555 timer IC. Our project consists of two water level sensors, one fixed at the top and other at the bottom. Working of this circuit is almost similar to a bi stable mutlivibrator. Simulation of this circuit is also given below. Definitely this will help you to do your academic project.

Circuit Diagram

Components Required

1. Power supply (6v)
2. NE 555 timer IC
3. Resistors (100Ωx2, 10kΩ)
4. Relay (6V, 30A)
5. BC 548 transistor x2
6. 1N4007 Diode

Working of Automatic water tank level controller

• We know the property of 555 timer IC, i.e. its output goes HIGH when voltage at the second pin(trigger pin) is less than 1/3 Vcc.

• Also we can reset back the IC by applying a LOW voltage at the 4th pin (Reset pin).

• In this project 3 wires are dipped in water tank. Let us define two water levels- Bottom (Low) level and Top (Up) level. One of the wire or probe is from Vcc.

• The probe from bottom level is connected to the trigger (2nd) pin of 555 IC. So the voltage at 2nd pin is Vcc when it is covered by water.

• When water level goes down, the 2nd pin gets disconnected(untouched) from water i.e. voltage at the trigger pin becomes less than Vcc. Then the output of 555 becomes high.

• The output of 555 is fed to a BC548 transistor, it energizes the relay coil and the water pump set is turned ON.

• While the water level rises, the top level probe is covered by water and the transistor becomes ON. Its collector voltage goes to Vce(sat) =0.2.

• The low voltage at the 4th pin resets the IC. So the output of 555 becomes 0V. Hence the motor will turn OFF automatically.

• For simple demonstration of this project you can use a DC motor directly at the output of 555 instead of relay.

• For practical implementation, you must use a relay. Rating of relay is chosen according to the load (Motor). 32 Ampere relay is best suited for domestic applications.

Also read: How to connect relay:Relays working with animation

Simulation of the Project

The mouse click on the bottom level and top level switches show the level of water, From the animation you can see that when the water is at the bottom level the motor starts working and when water reaches at top level motor stops functioning.
Also read:

• Numeric water level indicator
• Water tank overflow liquid level sensor alarm circuit

Now, here is your water level controller project. Was this project helpful to you? Don't forget to use the comment box below to share your views and clarify any doubt regarding the project.

PCB layout

Click on the images for enlarged view

Components Pin out