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

// Define the pins used for the ultrasonic sensor
const int trigPin = 4;
const int echoPin = 5;

// Define the pins used for the LEDs
const int redPin = 13;
const int yellowPin = 12;
const int greenPin = 14;

// Define the pin used for the buzzer
const int buzzerPin = 27;

// Create a LiquidCrystal_I2C object for the LCD
LiquidCrystal_I2C lcd(0x27,16,2);

void setup() {
  // Initialize the serial communication
  Serial.begin(9600);

  // Initialize the ultrasonic sensor pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

   // Initialize the LED pins
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(yellowPin, OUTPUT);

   // Initialize the buzzer pin
  pinMode(buzzerPin, OUTPUT);

  // Initialize the I2C LCD
  lcd.init();
  lcd.backlight();

  // Display a welcome message on the LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Flood Monitoring");
  lcd.setCursor(0, 1);     
  lcd.print("Depth: ");
  lcd.setCursor(11,1);
  lcd.print("cm");
}

void loop() {
  // Trigger the ultrasonic sensor by sending a 10 microsecond pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure the duration of the pulse from the ultrasonic sensor
  long duration = pulseIn(echoPin, HIGH);

  // Convert the duration to distance in centimeters
  int distance = duration * 0.034 / 2;

  // Print the distance to the serial monitor
  Serial.println(" cm");
  Serial.print(distance);
 
   // Display the distance on the LCD
  lcd.setCursor(7, 1);
  lcd.print(distance);

 
   // Blink the LED colors based on the distance
  if (distance < 30) {
    digitalWrite(redPin, HIGH);
    delay(300);
    digitalWrite(redPin, LOW);
    delay(300);
    
    digitalWrite(greenPin, LOW);
    digitalWrite(yellowPin, LOW);

  } else if (distance < 60) {
    
    digitalWrite(redPin, LOW);
    digitalWrite(greenPin, LOW);

     digitalWrite(yellowPin, HIGH);
    delay(300);
    digitalWrite(yellowPin, LOW);
    delay(300);
    
  } else {
    digitalWrite(greenPin, HIGH);

    digitalWrite(redPin, LOW);
    digitalWrite(yellowPin, LOW);
  
  }

    // If the distance is less than 59 centimeters, sound the buzzer
  if (distance < 30) {
    // Turn on the buzzer
    digitalWrite(buzzerPin, HIGH);
    tone(buzzerPin, 1000);

  } else if (distance < 60) {
    // Turn off the buzzer
    digitalWrite(buzzerPin, HIGH);
    tone(buzzerPin, 1000, 250);

  } else {
     digitalWrite(buzzerPin, LOW);
    tone(buzzerPin, 0);
  }
}