void setup() {
  Serial.begin(115200);
pinMode(13, OUTPUT);
pinMode(14, INPUT);
}

void loop() {
 digitalWrite(13, HIGH);
  delay(1000); 
  digitalWrite(13, LOW);

  float duration =pulseIn(14,HIGH);
  int distance = duration *0.034/2;
  Serial.println(distance);
  delay(1000);
}