int time;
int distance;
void setup() {
  pinMode(13, OUTPUT);
  pinMode(12, INPUT);
  Serial.begin(9600);
  // put your setup code here, to run once:

}

void loop() {
  digitalWrite(13, LOW);
  delay(1000);
  digitalWrite(13, HIGH);
  delay(1000);
  digitalWrite(13, LOW);
  time= pulseIn(12,HIGH);
  distance= time*0.0346/2;
  Serial.println(distance);
  // put your main code here, to run repeatedly:

}