// Uji HC-SR04

int triggerPin = 9;
int echoPin = 10;
int jarak = 0;

long readHCSR04()
{
  pinMode(triggerPin, OUTPUT);  // Clear the trigger
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  // Sets the trigger pin to HIGH state for 10 microseconds
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  pinMode(echoPin, INPUT);
  // Reads the echo pin, and returns the sound wave travel time in microseconds
  return pulseIn(echoPin, HIGH);
}

void setup()
{
  Serial.begin(9600);
  Serial.println("Distance meter");
  delay(1000);
}

void loop()
{
  // measure the ping time in cm
  jarak = readHCSR04() * 0.0343 /2;
  Serial.print("Jarak : ");
  Serial.print(jarak);
  Serial.println(" cm");
  delay(100); // Wait for 100 millisecond(s)
}