Sadly, only 1.2% of the water on earth—which covers around 71 percent of the planet—is fit for human use.
We could start experiencing persistent water shortages as early as 2025 due to population growth, pollution, and climate change.
While there are already modest problems between countries and governments over who gets to share river water, we humans waste a lot of drinking water as a result of our carelessness.

It might not seem like much at first, but if your tap leaked one drop of water per second, it would only take you approximately five hours to lose approximately five liters of water—enough to keep a typical person alive for two days.

How therefore can this be stopped?

As always, technological advancement is the solution to this.

We can save water and live healthier lives if we switch out all of the manual taps for smart ones that open and close on their own. This is because we won’t have to use our dirty hands to control the tap.

Therefore, in this project, we will construct an automatic water dispenser that will dispense water to you when a glass is placed next to it using an Arduino and a solenoid valve.

Sounds nice, yes?

So let’s construct one…

Materials Required:

●Buck Converter

●12V solenoid valve



●Pipe (Suitable)

●Relay module

●IR Sensor

●Wires & 2 pin plug

●Jumper wires

●Pipe clips

Working concept:

The Automatic Water Dispenser has a very straightforward concept.
To determine whether a glass is in front of the dispenser, we will utilise an IR sensor.
The flow of water will be managed by a solenoid valve, which when activated will cause it to flow and when deactivated will stop it.
Therefore, we will create an Arduino programme that constantly checks to see whether anything is placed close to the tap; if so, the solenoid will be activated and wait until the object is removed; once the object is withdrawn, the solenoid will automatically switch off, cutting off the water supply.

Let’s start with IR Sensor:

IR sensor is type of sensor which uses infrared light to detect object which is placed ahead of it.

Every Infrared sensor consists of two main parts. IR transmitter LED and IR receiver/photo diode.

Working of IR sensor:

The work of IR transmitter LED is to transmit or radiate infrared waves.

Whereas work of IR receiver/photo diode is to receive those reflected transmitted infrared waves.  


Relays are electromechanical switch which means by changing input signal at trigger pin,we can turn on or off another electronic equipment.

Normally closed (NC)-  when coil in de-energized Common & NC contacts are short-circuit

Normally opened(NO)- when coil is energized Common & NO contacts are short-circuit.

Common- Common is connected to either NO or NC pin depends on coil voltage.

Solenoid valve:

Solenoid is an actuator assembly with sliding plunger inside stationary armature which experiences uniform magnetic field when electric current passes through it.

Working of solenoid valve:

Solenoid consists of electromagnetically inductive coil wound around armature of plunger. Wire wound in such way that plunger inside that armature is free to moved in and out in the space center of armature The movement of the plunger is used to provide a mechanical force to control fluid flow.


Step1: SMPS connection

●Connect plug to 2-core wire

●Connect AC 230V main supply to 12VDC SMPS

●Check output voltage of SMPS is 12V or not.

Step2 : Switch & buck converter connections

Step 3 :Buck converter connections

Step5 :IR sensor connections

Step6 :Relay connections

Step7 : Solenoid connections

Our automatic water tap completed… lets see how it works: