int cm = 0;

long bacaJarak (int TrigPin, int EchoPin)
{
  pinMode(TrigPin, OUTPUT);
  digitalWrite(TrigPin, LOW);
  digitalWrite(TrigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(TrigPin, LOW);
  pinMode(EchoPin, INPUT);
  return pulseIn(EchoPin, HIGH);
}

void setup() {
  Serial.begin(9600);
}

void loop() {
  cm = (0.03446 * bacaJarak(7, 8))/2;

  Serial.print("Jarak (cm) = ");
  Serial.println(cm);
  
  delay(100);
}