---

#define TRIG_PIN 3
#define ECHO_PIN 2
#define LED 4
void setup ()
{
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED, OUTPUT);
  Serial.begin(9600);
}
void loop()
{
  int duration, sm;
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);
  sm = duration / 58;
       Serial.print("Расстояние = ");
  Serial.println(sm);
  if (sm < 13) digitalWrite(LED, HIGH);
  else digitalWrite(LED, LOW);
  delay(100);
}