#define TRIG_PIN  16    
#define ECHO_PIN 17    
#define LED_PIN 13

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);  
  pinMode(LED_PIN, OUTPUT);  
  Serial.begin(9600);       
}

void loop() {
  long duration, distance;

 
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

 
  duration = pulseIn(ECHO_PIN, HIGH);


  distance = (duration / 2) / 29.1;

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


  if (distance < 10) {
    digitalWrite(LED_PIN, HIGH); 
    delay(500);                  
    digitalWrite(LED_PIN, LOW);  
    delay(500);                  
  } else {
    digitalWrite(LED_PIN, HIGH); 

  delay(100); 
  }
}