#include <LiquidCrystal.h>

// LCD pin configuration
const int rs = 7, en = 6, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

int trigpin = 9;
int echopin = 10;
float distance;
int traveltime;

const int buzzerPin = 12;  // Buzzer pin
const int ledPin = 0;      // LED pin

void setup() {
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
  pinMode(buzzerPin, OUTPUT);  // Set buzzer pin as output
  pinMode(ledPin, OUTPUT);     // Set LED pin as output
  lcd.begin(16, 2);
}

void loop() {
  digitalWrite(trigpin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin, LOW);

  traveltime = pulseIn(echopin, HIGH);
  distance = 0.034 * (traveltime / 2);

  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print(" cm");

  // Activate buzzer and LED if distance is less than or equal to 200 cm
  if (distance <= 200) {
    tone(buzzerPin, 1000);  // Turn on buzzer
    digitalWrite(ledPin, HIGH);    // Turn on LED
  } else {
    noTone(buzzerPin);  // Turn off buzzer
    digitalWrite(ledPin, LOW);     // Turn off LED
  }

  delay(200);
  lcd.clear();
}