const int trigPin = 9;
const int echoPin = 10;
const int buzzer = 11;
const int ledPin = 13;

long duration;
int distance;
int safetyDistance;

void setup() {
  // put your setup code here, to run once:
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);

  distance = duration * 0.034 / 2;

  safetyDistance = distance;
  if (safetyDistance <= 5) {
    digitalWrite(buzzer, HIGH);
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(buzzer, LOW);
    digitalWrite(ledPin, LOW);
  }

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