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

LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address for 16x2 LCD
const int triggerPin = 7; // Ultrasonic sensor trigger pin
const int echoPin = 6;   // Ultrasonic sensor echo pin
const int buzzerPin = 12;  // Buzzer pin
const int relayPin = 8;   // Relay pin
const int greenLED = 4;   // Green LED pin
const int yellowLED = 5;  // Yellow LED pin
const int redLED = 2;     // Red LED pin

const int maxDistance = 400;  // Maximum range of the ultrasonic sensor in cm
const int numParts = 3;       // Number of parts to divide the range into
const int partDistance = maxDistance / numParts;  // Distance for each part

void setup() {
  pinMode(triggerPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(relayPin, OUTPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  
  lcd.init();
  lcd.backlight();
}

void loop() {
  long duration, distance;
  
  // Trigger the ultrasonic sensor
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);

  // Measure the time it takes for the pulse to return
  duration = pulseIn(echoPin, HIGH);

  // Calculate the distance in centimeters
  distance = (duration / 2) / 29.1;

  // Determine the water level description
  String waterLevel = "Unknown";

  if (distance < partDistance) {
    waterLevel = "Empty";
    digitalWrite(greenLED, LOW);
    digitalWrite(yellowLED, LOW);
    digitalWrite(redLED, HIGH);
    digitalWrite(buzzerPin, HIGH);
    digitalWrite(relayPin, HIGH); // Turn on the relay (e.g., to pump water)
  } else if (distance < partDistance * 2) {
    waterLevel = "Half";
    digitalWrite(greenLED, LOW);
    digitalWrite(yellowLED, HIGH);
    digitalWrite(redLED, LOW);
    digitalWrite(buzzerPin, LOW);
    digitalWrite(relayPin, LOW); // Turn off the relay
  } else {
    waterLevel = "Full";
    digitalWrite(greenLED, HIGH);
    digitalWrite(yellowLED, LOW);
    digitalWrite(redLED, LOW);
    digitalWrite(buzzerPin, LOW);
    digitalWrite(relayPin, LOW); // Turn off the relay
  }

  // Display the water level and distance on the LCD with proper formatting
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Water Level: ");
  lcd.print(waterLevel);
  lcd.setCursor(0, 1);
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print(" cm");

  delay(1000); // Delay for one second between readings
}