Water Or Liquid Level Sensor Relay Switch

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In this tutorial, we are making a simple project of Water Or Liquid Level Sensor Relay Switch. This circuit will switch on or off electronic appliances at the desired level of water. It detects the level of water and activates the relay when water reaches the desired level or contain their gets full. Relay is used to connect any load or electronic appliance with the circuit. It is an inexpensive circuit as it is using only a few components like probes, diode relay, transistor, and a variable resistor.

You can easily make this circuit at home whether you are familiar with electronics or not. Just buy the hardware and follow this tutorial and you will have a DIY water level sensor relay switch.

2N2222 NPN General Purpose Transistor

Hardware Components

The following components are required to make Water Level Sensor Circuit

S.noComponentsValueQty
1.Probes2
2.Variable Resistor300K1
3.Diode1N40011
4.Relay6V1
5.Transistor 2N22221
6.Battery6V1

2N2222 Pinout

2N2222-Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N2222

Water Level Sensor Circuit

Liquid level Sensor Circuit

Working Explanation

The operating voltage of this circuit is 6 volts. Probes are used to detect the water level. The desired water level is set by a 300K variable resistor. A 2N2222 NPN transistor is used which is working as a switch in this circuit. The relay of 6V is connected at the output of this circuit so that you can connect any load (electronic appliance) with it.

When the probes detect the water they start conducting electricity and send the voltage to the circuit. The transistor will receive its required voltage and activates which results in the activation of Relay. Now it’s up to you whether you want to turn on or off the electronic appliance connected with a relay.  Always use a relay of the same value as the input supply voltage.

Applications and Uses

  • Water tanks
  • Aquariums
  • Pool