Water covers about 71% of the earth, but sadly there is only drinking water in 2.5% of it. In 2025 we can expect perennial water shortages due to increased population, pollution, and climate change. We waste a lot of drinking water each year due to human negligence. On one hand, there are a number of minor disputes among nations and states regarding water sharing rivers, and on the other, there are national disputes among states regarding water sharing rivers. One gallon of water is enough for an average human to live two days if your tap drips a drop of water every second. This might not seem like a big amount of water at first, but it would take you about five hours to waste one gallon of water. This problem can be solved through technology improvement. The answer always lies in technology development. The water consumption rate can be drastically decreased by replacing all manual taps with a smart faucet that automatically opens and closes without requiring us

to touch the handle. Therefore, we will build a Solenoid Valves and Arduino based Automated Water Dispenser that can automatically dispense water to a glass when it is placed near it.

Solenoid Valve, Arduino Uno (any version) HCSR04 – Ultrasonic Sensor IRF540 MOSFET, 1k and 10k Resistor Breadboard, Connecting Wires Working Concept The water dispenser works by dispensing water at the touch of a button. A HCSR04 Ultrasonic Sensor will be used to verify that no glass is placed in front of the dispenser. A solenoid valve will control the flow of water. Which generates electricity to operate when activated, and de- energizes when not in use. The solenoid will be turned on and will wait until the object is removed. We will write an Arduino program that checks if anything is placed near the tap, on the other hand if it is, the solenoid will be turned off, when you remove the object, the solenoid will turn off the water supply automatically.

An electromechanical solenoid containing a 12-volt battery is used in this project. It has a continuous current capacity of 700mA. In other words, when the valve is on, it uses about 700mA to keep it on. Hence, a Solenoid driver circuit needs a switching driver to operate an Arduino board that operates with 5V and hence requires a 5V switching driver circuit. IRF540N is the MOSFET used in this project and its switching device is referred to as a N-Channel MOSFET with the Gate, Source and Drain pins originating from pin 1. According to the circuit diagram, the Arduino's Vin pin powers the solenoid's positive terminal. As the Arduino will be powered by a 12V adapter and its Vin pin is 12V, the control of the solenoid can be performed. Several connections are made between the negative terminal and the ground via the MOSFET’s Source and Drain pins. Only if the MOSFET is switched on will the solenoid be powered. Turning the MOSFET on or off is done with the gate pin. A gate pin grounded to ground will remain off while a gate voltage applied to it will turn it on. The gate pin of the MOSFET is pulled down to ground by a 10k resistor when no power is applied to it. A 1K resistor limits the current flowing to Arduino pin 12, which controls the MOSFET.

The Ultrasonic Sensor is powered by connecting a power supply to the Arduino's +5V and ground pins. To pins 8 and 9, respectively, are connected the trigger and echo pins. The Ultrasonic sensor can then be programmed to make use of the Arduino in order to detect objects and turn on the MOSFET if one is detected. My circuit was somewhat like this below after connecting all the wires. The whole circuit is simple and can be easily built on a breadboard.