Soil Moisture Sensor for Arduino

Wire the moisture sensor to Arduino.

1. Connect the moisture sensor's GND pin to Arduino GND.
2. Connect the moisture sensor's VCC pin to Arduino 5V.
3. Connect the moisture sensor's SIG (signal) pin to Arduino analog pin A3.

Wire the LCD to Arduino.

1. Connect the LCD GND pin to Arduino GND.
2. Connect the LCD VCC pin to Arduino 5V.
3. Connect the LCD SDA pin to Arduino A4.
4. Connect the LCD SCL pin to Arduino A5.

Program the Arduino to read moisture and display it.

1. Open Arduino IDE and create a new sketch.
2. Copy the complete sketch below into your IDE.
3. If you're using a different LCD library or pin configuration, adjust the LiquidCrystal initialization line.
4. Connect your Arduino via USB.
5. Under Tools, select Arduino Uno as the board and the correct port.
6. Click Upload.

#include <LiquidCrystal.h>

// Initialize LCD with pins (RS, E)
LiquidCrystal lcd(5, 4);

const int analogInPin = A3;
int sensorValue = 0;

void setup() {
  lcd.begin(16, 2);
  delay(100);
}

void loop() {
  lcd.clear();
  lcd.print("Soil Moisture:");
  
  sensorValue = analogRead(analogInPin);
  
  lcd.setCursor(0, 1);
  lcd.print(sensorValue);
  
  delay(300);
}

Verify the sensor responds to moisture changes.

1. Insert the moisture sensor probes into dry soil and note the reading on the LCD.
2. Water the soil and watch the reading increase.
3. Remove the sensor and dry it, then test in a glass of water for the maximum reading.
4. Use these readings to determine your plant's ideal moisture range.