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

#define TRIGGER_PIN 3      // Ultrasonic sensor trigger pin
#define ECHO_PIN 2         // Ultrasonic sensor echo pin
#define BUZZER_PIN 4       // Piezo buzzer pin
#define LED_RED_PIN 5      // Red LED pin
#define LED_YELLOW_PIN 6   // Yellow LED pin
#define LED_GREEN_PIN 7    // Green LED pin

#define LCD_ADDRESS 0x27   // I2C address of the LCD
#define LCD_COLUMNS 16     // Number of LCD columns
#define LCD_ROWS 2         // Number of LCD rows

LiquidCrystal_I2C lcd(LCD_ADDRESS, LCD_COLUMNS, LCD_ROWS);

void setup() {
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_RED_PIN, OUTPUT);
  pinMode(LED_YELLOW_PIN, OUTPUT);
  pinMode(LED_GREEN_PIN, OUTPUT);

  lcd.begin(LCD_COLUMNS, LCD_ROWS);
  lcd.backlight();

  Serial.begin(9600);
}

void loop() {
  long duration;
  int distance;

  // Trigger the ultrasonic sensor
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);

  // Measure the echo duration to calculate the distance
  duration = pulseIn(ECHO_PIN, HIGH);
  distance = duration * 0.034 / 2;  // Calculate distance in centimeters

  // Display the distance on the LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print(" cm");

  // Check the distance and provide feedback using LEDs and buzzer
  if (distance <= 20) {
    // Play a tone and turn on the red LED for close proximity
    tone(BUZZER_PIN, 1000, 200);
    digitalWrite(LED_RED_PIN, HIGH);
    digitalWrite(LED_YELLOW_PIN, LOW);
    digitalWrite(LED_GREEN_PIN, LOW);
  } else if (distance <= 50) {
    // Play a tone and turn on the yellow LED for moderate proximity
    tone(BUZZER_PIN, 800, 200);
    digitalWrite(LED_RED_PIN, LOW);
    digitalWrite(LED_YELLOW_PIN, HIGH);
    digitalWrite(LED_GREEN_PIN, LOW);
  } else {
    // Turn on the green LED for safe distance
    noTone(BUZZER_PIN);
    digitalWrite(LED_RED_PIN, LOW);
    digitalWrite(LED_YELLOW_PIN, LOW);
    digitalWrite(LED_GREEN_PIN, HIGH);
  }

  delay(200);  // Adjust the delay as needed
}