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Arduino project · Water and plants · Easy

Soil Moisture Ring

A ring shows how wet the soil of a plant is.

What you will learn

  • How a soil probe measures moisture
  • How a ring shows a level
  • How to calibrate dry and wet

How it works

The probe gives 0 to 100 percent. Few pixels mean dry soil and a full ring means wet soil.

Try this next

  • Add a pump relay below 30 percent.
  • Show the number on an LCD.
  • Make the ring red when dry.

The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.

1Choose your Arduino board
2Build the circuit
Parts: sensors and actuators (tap to show or hide)

Try the inputs (virtual sensors)

Pins (you can change them)

PartArduino pin (change it here)How to wire it

Every wire, one by one

Red rail = 5 V from the Arduino 5V pin. Black rail = GND. The coloured wires carry signals. Match the wire colours on the drawing to this list.

#ColourFrom (part and leg)To
3Define the sequence

Steps run from top to bottom, then start again. While the simulation runs, the active step is highlighted in green.

4Arduino code

5Parts list and where to buy

Quantities come from the parts you added. The store links open a search for that item on Robu.in, Amazon.in and ThinkRobotics, so you always see what is in stock today. Check the model, voltage and price before you order.

#ItemQtySearch termBuy / compare
6Export

The PDF has the circuit sketch, pin table, every wire, sequence, full code, the parts list with store links, do’s and don’ts for each part, and the safety notes. The project file lets you come back and keep editing.

7Learn: do’s, don’ts, cautions and tips

In the real world

A plant that tells you when it is thirsty

Lower the soil moisture in the simulator. The soil dries and the plant starts to droop.

Tip: use the gold tab at the bottom of the circuit drawing to pull the real-world view up over the Arduino board. Your parts stay visible above it, so you can press a button and watch the real scene react.