Smart Plant Watering System

Wire the soil moisture sensor to Arduino.

1. Connect the moisture sensor VCC to Arduino 5V.
2. Connect the moisture sensor GND to Arduino GND.
3. Connect the moisture sensor analog output to Arduino A0.
4. Insert the sensor probes into the soil of your plant.

Wire the relay module to control the water pump safely.

1. Connect the relay module VCC to Arduino 5V.
2. Connect the relay module GND to Arduino GND.
3. Connect the relay IN pin to Arduino digital pin 7.
4. Connect the water pump positive wire to the relay NO (Normally Open) terminal.
5. Connect the relay COM (Common) terminal to the positive terminal of your 12V power supply.
6. Connect the water pump negative wire to the power supply GND.
7. Connect the Arduino GND to the power supply GND (common ground).

Connect tubing from pump to plants.

1. Place the water pump in your reservoir (bucket or tank).
2. Attach flexible tubing to the pump output.
3. Route the tubing to your plant(s).
4. Test manually by powering the pump briefly to check for leaks.

Program the Arduino to water when soil is dry.

1. Open Arduino IDE and copy the complete irrigation sketch below.
2. Adjust the DRY_THRESHOLD value based on your sensor readings (lower = drier soil).
3. Upload to your Arduino.
4. Open Serial Monitor (9600 baud) to see moisture readings and pump status.

const int moisturePin = A0;
const int pumpPin = 7;

const int DRY_THRESHOLD = 400;
const int WATERING_TIME = 5000;

unsigned long lastWatering = 0;
const unsigned long WATERING_INTERVAL = 3600000;

void setup() {
  pinMode(pumpPin, OUTPUT);
  digitalWrite(pumpPin, LOW);
  
  Serial.begin(9600);
  Serial.println("Smart Watering System Starting...");
}

void loop() {
  int moistureLevel = analogRead(moisturePin);
  
  Serial.print("Moisture Level: ");
  Serial.println(moistureLevel);
  
  unsigned long currentTime = millis();
  
  if (moistureLevel < DRY_THRESHOLD && 
      (currentTime - lastWatering > WATERING_INTERVAL)) {
    
    Serial.println("Soil is dry. Watering now...");
    digitalWrite(pumpPin, HIGH);
    delay(WATERING_TIME);
    digitalWrite(pumpPin, LOW);
    
    lastWatering = currentTime;
    Serial.println("Watering complete.");
  } else {
    Serial.println("Soil moisture OK.");
  }
  
  delay(60000);
}

Fine-tune moisture threshold and watering duration.

1. Open Serial Monitor and observe moisture readings.
2. Note the reading when soil is completely dry.
3. Note the reading after watering.
4. Adjust DRY_THRESHOLD in the code to trigger watering at your desired moisture level.
5. Adjust WATERING_TIME based on how much water your plant needs.
6. Monitor for 24 hours to ensure the system waters at the right times.