#include <Wire.h> // Wire library for I2C communication
#include <LiquidCrystal_I2C.h> // LCD library for I2C interface
#include <NewPing.h> // NewPing library for ultrasonic sensor

#define TRIGGER_PIN 18 
#define ECHO_PIN 17 
#define MAX_DISTANCE 200 

#define BUZZER_PIN 12 
#define RED_LED_PIN 19 
#define BLUE_LED_PIN 26 

LiquidCrystal_I2C lcd(0x27, 16, 2); 

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); 

void setup() {
  Serial.begin(9600); // Start serial communication
  lcd.init(); // Initialize LCD
  lcd.backlight(); // Turn on backlight

  pinMode(BUZZER_PIN, OUTPUT); 
  pinMode(RED_LED_PIN, OUTPUT); 
  pinMode(BLUE_LED_PIN, OUTPUT); }

void loop() {
  float distance = sonar.ping_cm(); // Read distance from ultrasonic sensor
//  float distance=120;
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.setCursor(0, 1);
  Serial.println(distance);
  delay(2000); 

  // Check for danger conditions
  if (distance > 100) { 

    digitalWrite(RED_LED_PIN, HIGH); 
    digitalWrite(BLUE_LED_PIN, LOW); 
    lcd.clear(); 
    lcd.setCursor(0, 0);
    lcd.print("Danger!"); // Display danger on LCD
    tone(BUZZER_PIN, 1000, 1000);
  } 
   else {
    digitalWrite(RED_LED_PIN, LOW); // Turn off red LED
    digitalWrite(BLUE_LED_PIN, HIGH); // Turn on blue LED
    lcd.clear(); // Clear the display before showing safe message
    lcd.setCursor(0, 0);
    lcd.print("Safe"); // Display safe on LCD
  }

  delay(1000); 
  }