How to make a Simple Automatic Water Level Controller

Hello friends, Welcome to this electronics tutorial. In this tutorial, you will know how to make a Automatic Water level Controller. This project will act as a Smart controller for the motor which turn on the motor when the water level is below the medium level of the Water tank and turn off the motor when the water tank gets full. The total cost of making this project is only under Rs.60/- only. and once you make it, you will find this as a Cost efficient project. So friends, let's begin to make this project.

Step1 - Things Needed.

[Circuit Parts]

> BC547 NPN Transistor - 2 pieces.
> 100 ohm Resistor - 4 pieces.
> 12v relay - 4 pieces.
> Led (optional) [ Red - 1 piece, White - 1 piece.] {you may choose any color you like}.
> Project Circuit Board (PCB) - 1 piece. 
> Some Wires.

[Miscellaneous Parts]

> 5 Pin AC Socket - 1 piece. (used as a power supply socket for motor/pump).
> Switch - 1 piece. (use to switch on and off the Circuit).
> Project box - 1 piece. ( for casing the project).
> 12V 1A/2A Power Supply Circuit - 1 piece.(Used to power the circuit via AC).
> Some length of Mains Wires. (used to power the power supply Circuit).

Step 2 - Tools Needed.

> Soldering Iron.
> Soldering Wire.
> Soldering Flux.
> Hot Glue Gun.
> Wire Cutter.

Step 3 - Studying the Circuit Diagram.

Circuit Diagram

So friends, I request you to please understand the Circuit Diagram before proceeding further. This will help you to make any modification in the Circuit.

Circuit Diagram Download Link

Working of the Circuit :)

So friends, as you can see this is a Complicated Circuit to Understand. So, If you can't Understand then below is the explanation of the working of the Circuit. So, let's begin to know about the working of the Circuit.

The working of the Circuit is in two stages/level - 
(1) Water level Sensor.
(2) Motor Controller/Main Brain.

Now, let's begin to know the explanation of working of these two stages.

Relay Declaration

> Water Level Sensor - This Circuit Works as when the sensor wires touches the Water, (+) pole of  the Battery gets connected to base of BC547 NPN Transistor because of the Conductance in water. Which Switches the transistor in on position and in the Circuit, One pin of relay is already Connected to (+) terminal of Battery. So, for the relay to gets on, the relay requires the (-) terminal of the battery to be connected to another pin. and this condition is fulfilled by the switching of the transistor. which as a result turns on the relay. The reason behind this is the switching of the transistor  connects the emitter to collector which supply the (-) voltage to the pin of the relay which is connected to Collector pin of transistor. 

When the sensor wires is not touching the water, the Base of NPN is not getting any (+) voltage from any Source to be in on position and as a result the relay gets turn off.

This is the way of the working of this stage. Now Coming towards the second stage.

> Motor Controller/Main Brain - This Circuit processes the Input received from the Water level Sensor and as a Output, It controls the motor according to different water level.So, you can Considered it to be the brain of this Circuit. So friends, let's begin to know about the working of this part in deep.

< When the tank is empty >
Both relay is in off position at this stage. So, the positive wire from battery which is Connected to "Common" of the water level Sensors relay gets connected to "NC" (Normally Closed) pin of relay. and In the Circuit the "NC" of the medium level water sensor relay is connected to one pin of relay"C" and another pin of relay "C" is already Connected to (-) wire from battery. So, the relay gets proper power to turn on and as a result, the motor starts running when the tank is empty.

< When the Water touches the medium level Water Sensor >
Medium level water sensor relay gets on at this stage. which breaks the connection between "Common" and "NC" of the relay and this connection gets replaced by a new Connection between "Common" and "NO" of relay. This new Connection stop the supply of (+) voltage to the relay "C" but In the Circuit the higher relay is still off and within the relay the connection is same as previously described. The "NC" Pin of this relay is connected to "NC" of main relay and the main relay is not getting any power to operate hence  "NC" gets connected to "Common" of the relay and in the circuit the common is connected to the relay"C". So, the relay "C" gets the (+) voltage supply to operate and as a result, the relay is still on and the motor is still running.

< When the water touches the higher level Water Sensor >
Both relay gets on at this Stage which as a result breaks the connection between "NC" and "Common" of both relay. This is the reason which breaks the (+) voltage supply  to the relay "C" and Main relay and both relay gets off which stops the motor.

Now friends, the question that arises here is that when the water level in the tank falls slightly, whether the motor gets on or not?. The answer is that it will remain off until the water level falls below the medium level of water tank. Now, let's explain the answer of this question.

(Answer Explained)

When the water level falls slightly below the higher level of tank. Higher relay gets off and the "NC" of the relay is now connected to "Common" pin. Now, In the Circuit the "NC" of the relay is connected to "NO" pin of main relay and the main relay is off because it is not getting any (+) voltage supply from medium level relay. So,  the "COM" of main relay is connected to "NC" not to "NO". So, the (+) voltage supply which is required for relay "C" to gets on is not supplying to relay and the motor is off and this process is going on and help in the proper functioning of the circuit.

So friends, this is the explanation of the working of this Circuit. 

Simple Automatic Water Level Controller.

I hope you like and enjoy this electronics tutorial. If you have any problem then, ask me in Comment box.