Materials Used

Wiring Instructions

Water Sensor: S (Signal) → A0, + → 5V, – → GND
LEDs: Green=Pin 2, Yellow=Pin 3, Red=Pin 4 (each through 220–330Ω resistor to GND)
Buzzer: + → Pin 5, – → GND

Project Photos & Demo

Arduino Code

// Water Level Detector
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int sensorPin = A0;
const int greenLED = 8;
const int yellowLED = 9;
const int redLED = 10;
const int buzzer = 11;

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

  pinMode(greenLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  pinMode(buzzer, OUTPUT);

  lcd.setCursor(0, 0);
  lcd.print("Water Level");
  lcd.setCursor(0, 1);
  lcd.print("Detector Ready");
  delay(2000);
}

void loop() {
  int waterLevel = analogRead(sensorPin);
  int percentage = map(waterLevel, 0, 1023, 0, 100);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Water Level:");
  lcd.setCursor(0, 1);
  lcd.print(percentage);
  lcd.print(" %");

  Serial.print("Water Level: ");
  Serial.print(percentage);
  Serial.println(" %");

  // Turn off all indicators
  digitalWrite(greenLED, LOW);
  digitalWrite(yellowLED, LOW);
  digitalWrite(redLED, LOW);
  noTone(buzzer);

  if (percentage < 30) {
    // Low water level
    digitalWrite(greenLED, HIGH);
  } else if (percentage < 70) {
    // Medium water level
    digitalWrite(yellowLED, HIGH);
  } else {
    // High water level - Alert!
    digitalWrite(redLED, HIGH);
    tone(buzzer, 1000);
    delay(500);
    noTone(buzzer);
    delay(500);
  }

  delay(1000);
}

🔧 Troubleshooting

Water level sensor not responding? Here's how to fix it:

What You Learned