Example Code for Arduino-Soil Moisture Detection

Hardware Preparation

• DFRduino UNO x1
• Capacitive Soil Moisture Sensor x1
• Jumper Cable x3

Software Preparation

• Arduino IDE V1.6.5 Click to Download Arduino IDE

Wiring Diagram

The final output value is affected by probe insertion depth and how tight the soil packed around it is. We regard "value_1" as dry soil and "value_2" as soaked soil. This is the sensor detection range.
For example: Value_1 = 520; Value_2 = 260.
The range will be divided into three sections: dry, wet, water. Their related values are:

• Dry: (520 430]
• Wet: (430 350]
• Water: (350 260]

Sample Code

/***************************************************
 This example reads Capacitive Soil Moisture Sensor.

 Created 2015-10-21
 By berinie Chen <[email protected]>

 GNU Lesser General Public License.
 See <http://www.gnu.org/licenses/> for details.
 All above must be included in any redistribution
 ****************************************************/

/***********Notice and Trouble shooting***************
 1.Connection and Diagram can be found here: https://www.dfrobot.com/wiki/index.php?title=Capacitive_Soil_Moisture_Sensor_SKU:SEN0193
 2.This code is tested on Arduino Uno.
 3.Sensor is connect to Analog 0 port.
 ****************************************************/

const int AirValue = 520;   //you need to replace this value with Value_1
const int WaterValue = 260;  //you need to replace this value with Value_2
int intervals = (AirValue - WaterValue)/3;
int soilMoistureValue = 0;
void setup() {
  Serial.begin(9600); // open serial port, set the baud rate to 9600 bps
}
void loop() {
soilMoistureValue = analogRead(A0);  //put Sensor insert into soil
if(soilMoistureValue > WaterValue && soilMoistureValue < (WaterValue + intervals))
{
  Serial.println("Very Wet");
}
else if(soilMoistureValue > (WaterValue + intervals) && soilMoistureValue < (AirValue - intervals))
{
  Serial.println("Wet");
}
else if(soilMoistureValue < AirValue && soilMoistureValue > (AirValue - intervals))
{
  Serial.println("Dry");
}
delay(100);
}