In this project, we’ll see how to display and calculate the filling percentage of your water tank. This can be very useful if you have a tank for collecting rainwater or if you have a submerged tank and cannot see the water level.

Required materials

Now, here are the materials needed for the project:

  • An Arduino Uno board

  • A 16×2 Liquid Crystal LCD screen

  • A water pump

  • A distance sensor

  • A potentiometer

  • A relay

  • A 220-ohm resistor

  • An external power supply (9V battery)

  • Jumper wires (around fifteen!)

How does the filling system work?

There are two parts to this project:

  1. Detecting the filling level of the tank

  2. Watering with water from the tank

For detecting the filling level, we use a distance sensor aimed at the bottom of the tank. The water at the bottom reflects the signal sent by the sensor back, which returns a distance measurement. We then display the filling percentage based on the tank’s original size.

To water your garden, we use a water pump. It runs on 9V, so we need an external power supply because the Arduino board can only provide up to 5V. We use a relay to control the water pump from the Arduino board.

Additionally, we added a switch to turn off the pump when you finish watering. This switch controls only the pump, allowing you to keep monitoring the filling level even when the pump is off.