int trig = 9;
int echo = 10;
int led = 12;

void setup() {
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
  pinMode(led, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  long duration;
  int distance;

  digitalWrite(trig, LOW);
  delayMicroseconds(2);

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

  duration = pulseIn(echo, HIGH);
  distance = duration * 0.034 / 2;

  if (distance < 10) {
    digitalWrite(led, HIGH);
  } else {
    digitalWrite(led, LOW);
  }

  delay(200);
}