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

// LCD address (0x27 or 0x3F)
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Ultrasonic pins
#define trigPin 9
#define echoPin 10

// Buzzer pin
#define buzzer 8

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzer, OUTPUT);

  lcd.init();
  lcd.backlight();

  Serial.begin(9600);
}

void loop() {
  // Trigger ultrasonic pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read echo
  duration = pulseIn(echoPin, HIGH);

  // Calculate distance
  distance = duration * 0.034 / 2;

  // Display distance
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Distance:");
  lcd.setCursor(0, 1);
  lcd.print(distance);
  lcd.print(" cm");

  Serial.print("Distance: ");
  Serial.println(distance);

  // Condition check
  if (distance <= 10 && distance > 0) {
    digitalWrite(buzzer, HIGH);
    
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Object Detected");
    lcd.setCursor(0, 1);
    lcd.print(distance);
    lcd.print(" cm");
  } else {
    digitalWrite(buzzer, LOW);
  }

  delay(500);
}