Capacitive soil moisture sensor v1.2 Arduino code | Step by step instructions

Hello guys, welcome back. Today we are going to talk about how the “capacitive soil moisture sensor ” works with Arduino. Also, soil moisture can be easily monitored by this sensor. An LCD is also used to monitor this value. Once this sensor is inserted into the soil we can get the values ​​through this. It can be used primarily to make irrigation systems.

How does work Capacitive soil moisture sensor?

The soil moisture sensor measures the change in capacitance caused by changes in the electron content of the soil. A 555 IC circuit is also included to measure this capacitance. This circuit produces a voltage proportional to the capacitance of the sensor. This voltage level is between 1.2v and 3v. And we can get that voltage through the analog pin. It is also known as soil moisture. This sensor requires a voltage of 3.2v to 5v to operate. However, the built-in voltage regulator completes the functionality and the sensor is made of corrosion-resistant materials so it can be used for a long time.

We can see three pins in this sensor. Connect the cathode / GND terminal to the GND pin. A 5v voltage should be provided for the VCC terminal. Also, we can get the soil moisture values using the AOUT PIN.

OK, now we will learn step by step how this sensor works with Arduino. The required components are given below.

• Arduino UNO board x 1  — Amazon / Our Store
• Capacitive soil moisture sensor x 1 — Amazon  / Our store
• LCD display x 1 — Amazon / Our Store
• I2C module x 1 — Amazon / Our Store
• Jumper wires — Amazon / Our Store

Disclosure: These Amazon links are Affiliate links. As an Amazon Associate, I earn from qualifying purchases.

Step 1

Firstly, identify these components.

Step 2

Secondly, connect these components. For that, use the circuit diagram below.

Step 3

Thirdly, let us prepare the required program for this. It is given below.

• The complete program of this project – Download

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd (0x27, 16, 2);
#define sensor A2
#define wet 210
#define dry 510
 
void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
}
 
void loop() {
  int value = analogRead(sensor);
  Serial.println(value);
  lcd.setCursor(1, 0);
  lcd.print("Moisture Value");
  lcd.setCursor(3, 1);
  lcd.print(value);
  lcd.print(" ");
  lcd.setCursor(7,1);
  lcd.print("--");
  int pre = map(value, wet, dry, 100, 0);
  lcd.setCursor(10, 1);
  lcd.print(pre);
  lcd.print("%");
  lcd.print(" ");
}

Code explanation

Firstly, includes the I2C library. After, an object was created for the I2C library. It then includes the I2C library address and the LCD height and width.

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd (0x27, 16, 2);

Secondly, defines the objects for sensor PIN, wet value, and dry value.

#define sensor A2
#define wet 210
#define dry 510

Thirdly, the I2c library is initialized in the void setup.

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
}

Finally, values are obtained from the soil moisture sensor and added to the variable called “value”. Later, these values are displayed on the LCD

void loop() {
  int value = analogRead(sensor);
  Serial.println(value);
  lcd.setCursor(1, 0);
  lcd.print(“Moisture Value”);
  lcd.setCursor(3, 1);
  lcd.print(value);
  lcd.print(” “);
  lcd.setCursor(7,1);
  lcd.print(“–“);
  int pre = map(value, wet, dry, 100, 0);
  lcd.setCursor(10, 1);
  lcd.print(pre);
  lcd.print(“%”);
  lcd.print(” “);
}

Step 4

OK, now select the correct board and port. Then, upload this code.

Now you can test this project. For that, insert the sensor into the soil bowl and view the readings on the LCD. The full video guide is below. So, we will meet in the next tutorial. Have a good day.

Capacitive soil moisture sensor v1.2 Arduino code | Step by step instructions