Use a Moisture Sensor with Arduino

Difficulty
Moderate
Steps
7

For the absent-minded green thumbs, you'll need to use one of these moisture sensors!

In this guide, you will learn how you can use a moisture sensor with an Arduino, to determine the amount of moisture in a substance.

After completing this guide, you could create an Arduino plant watering system or a simple moisture detector for your beloved garden plants.


Step 1  Get your moisture sensor and probe.

  • You will find a moisture sensor probe and breakout module

Step 2  Connect the Probe to the Breakout Module.

  • Connect the Probe to the Breakout Module.
  • The order of the wires doesn't matter.

Step 3  Connect the 5V line from the Arduino to the Module.

  • Connect the 5V line from the Arduino to the Module.

Step 4  Connect the Ground line from the Arduino to the Module.

  • Connect the Ground line from the Arduino to the Module.

Step 5  Connect Analogue 0 to the Module.

  • Connect Arduino Analogue 0 to the Module.

Step 6  Grab your code for the Moisture Sensor.


              int ledPin = 13; // Wet Indicator at Digital Pin D13
int sensor = 0; // Soil Sensor input at Analog Pin A0
int value = 0;

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);
  Serial.println("SOIL MOISTURE SENSOR");
  Serial.println("-----------------------------");
}

void loop() {
  value = analogRead(sensor);
  value = value / 10;
  Serial.println(value);
  if (value < 50) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }
  delay(1000);
}
            
  • Copy this code and load it into the Arduino IDE and Upload it
  • Open the Serial Monitor
  • Out of moist soil you should get a reading around 100
  • Once in moist soil or a glass of water you should get <40

Step 7  Make sure your Christmas Tree doesn't dry out.

  • Each year our Christmas Tree drys out and turns brown long before Christmas Day
  • This year, using the moisture sensor we are going to make sure it alway has enough water.