// Ultrasonik
  const int triggerPin = 7;
  const int echoPin = 6;
  unsigned int duration;
  unsigned int jarak;  
  // --- Batas ----

  int ledMerah = 13;
  int ledHijau = 12;

  int waktu1 = 100;		// waktu / delay

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

    pinMode(triggerPin, OUTPUT);	// pin Triger
    pinMode(echoPin, INPUT); 		// pin Echo

    pinMode(ledMerah, OUTPUT);
    pinMode(ledHijau, OUTPUT);
  }


  void loop() {
    ultra1(); 
    Serial.println(jarak);
    // delay(waktu1);
    
    if(jarak < 150){
       digitalWrite(ledMerah, HIGH);
       digitalWrite(ledHijau, LOW);
    }

    if(jarak > 150){
       digitalWrite(ledMerah, LOW);
       digitalWrite(ledHijau, HIGH);
    }

    delay(waktu1);
  }


  void ultra1() {
    digitalWrite(triggerPin, LOW);
    delayMicroseconds (2);
    digitalWrite(triggerPin, HIGH);
    delayMicroseconds (10);
    digitalWrite(triggerPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    jarak = (duration / 2) / 29.1;
  }