int trig_pin = 13;
int echo_pin = 12;

float distance;

void setup() {
  pinMode(trig_pin, OUTPUT);
  pinMode(echo_pin, INPUT);
  Serial.begin(9600); 
}

void loop() {
  distance = readUltrasonic();

  Serial.print("Distance: ");
  Serial.println(distance);
}

float readUltrasonic() {
  digitalWrite(trig_pin, LOW);
  delayMicroseconds(2);
  digitalWrite(trig_pin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig_pin, LOW);

  unsigned long duration = pulseIn(echo_pin, HIGH);
  float measuredDistance = 0.0344 / 2  * duration;

  return measuredDistance;
}