#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Define Ultrasonic Sensor Pins
const int trigPin = 5;
const int echoPin = 18;

// Define LED Pins
const int lowLED = 25;
const int midLED = 26;
const int highLED = 27;

// Initialize the LCD (address 0x27 for a 16x2 LCD)
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  
  // Set Ultrasonic Sensor Pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  // Set LED Pins
  pinMode(lowLED, OUTPUT);
  pinMode(midLED, OUTPUT);
  pinMode(highLED, OUTPUT);
  
  // Initialize LCD
  lcd.init();
  lcd.backlight();
}

void loop() {
  // Send a 10us pulse to trigger the sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Measure the echo pulse width
  long duration = pulseIn(echoPin, HIGH);
  
  // Calculate distance in cm
  float distance = (duration * 0.0343) / 2;
  
  // Display the distance on the LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Water Level:");
  lcd.setCursor(0, 1);
  lcd.print(distance);
  lcd.print(" cm");
  
  // Update LEDs based on water level
  if (distance > 200) {
    digitalWrite(lowLED, HIGH);
    digitalWrite(midLED, LOW);
    digitalWrite(highLED, LOW);
  } else if (distance <= 200 && distance > 100) {
    digitalWrite(lowLED, LOW);
    digitalWrite(midLED, HIGH);
    digitalWrite(highLED, LOW);
  } else if (distance <= 100) {
    digitalWrite(lowLED, LOW);
    digitalWrite(midLED, LOW);
    digitalWrite(highLED, HIGH);
  }
  
  // Wait before next measurement
  delay(1000);
}