Project42.Soil Moisture Sensor

Description

The soil moisture sensor or the hygrometer is usually used to detect the humidity of the soil. So, it is perfect to build an automatic watering system or to monitor the soil moisture of your plants.

The sensor is set up by two pieces: the electronic board (at the right), and the probe with two pads, that detects the water content (at the left).

The sensor has a built-in potentiometer for sensitivity adjustment of the digital output (D0), a power LED and a digital output LED, as you can see in the following figure.

Specification

Connect

Code

int rainPin = A0;
int ledPin = 13;

// you can adjust the threshold value
int thresholdValue = 800;

void setup(){
pinMode(rainPin, INPUT);
pinMode(ledPin, OUTPUT);  // Set the LED pin as the output mode
Serial.begin(9600);
}

void loop() {
// read the input on analog pin 0:
int sensorValue = analogRead(rainPin);
Serial.print(sensorValue);

if(sensorValue < thresholdValue){
    Serial.println(" - Doesn't need watering");
    digitalWrite(ledPin, LOW);  // If you don't need to water, turn off the LED
} else {
    Serial.println(" - Time to water your plant");
    // If you need to water, flash the LED quickly
    for(int i = 0; i < 5; i++){
    digitalWrite(ledPin, HIGH);
    delay(100);
    digitalWrite(ledPin, LOW);
    delay(100);
    }
    digitalWrite(ledPin, LOW);
}
delay(500);  //
}

Whenever the soil is short of water, the LED on the Arduino will flash five times continuously, and it will output “Time to water your plant” in the serial monitor.

If there is no shortage of water, the LED will not light up

Phenomenon