const int trigPin = 9;

const int echoPin = 10;

const int ledPin = 13;

void setup() {

pinMode(trigPin, OUTPUT);

pinMode(echoPin, INPUT);

pinMode(ledPin, OUTPUT);

}

void loop() {

  digitalWrite(trigPin, LOW);

  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);

  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH);

  int distance = duration * 0.034 / 2;

  if (distance < 10) {

      digitalWrite(ledPin, HIGH);

  } else {

      digitalWrite(ledPin, LOW);

  }
  
  delay(500);

}