#include <Wire.h>
#include <Adafruit_LiquidCrystal.h>  // For Adafruit I2C LCD
#include <NewPing.h>                  // For Ultrasonic distance measurement

#define TRIGGER_PIN  12  // Pin connected to the HC-SR04 Trigger
#define ECHO_PIN     13  // Pin connected to the HC-SR04 Echo
#define MAX_DISTANCE 200 // Maximum distance to measure (in cm)

#define BUZZER_PIN  26  // Pin connected to the Buzzer

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);  // Initialize ultrasonic sensor
Adafruit_LiquidCrystal lcd(0);                       // Initialize the I2C LCD

void setup() {
  // Start serial communication for debugging
  Serial.begin(9600);
  
  // Initialize the LCD screen
  lcd.begin(16, 2);
  lcd.setBacklight(LOW); // Turn off the backlight initially

  // Initialize buzzer pin as output
  pinMode(BUZZER_PIN, OUTPUT);

  // Set initial LCD message
  lcd.setCursor(0, 0);
  lcd.print("Distance Sensor");
}

void loop() {
  // Get the distance from the ultrasonic sensor
  int distance = sonar.ping_cm();

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

  // If an object is closer than 30 cm, trigger the buzzer
  if (distance > 0 && distance < 30) {
    tone(BUZZER_PIN, 1000); // Buzz at 1000 Hz frequency
    lcd.setCursor(0, 1);
    lcd.print("Object detected!");
  } else {
    noTone(BUZZER_PIN); // Turn off buzzer if distance is safe
  }

  delay(500);  // Delay to allow sensor to stabilize and reduce flicker on LCD
}