int const LED_HIJAU = 11;
int const LED_KUNING = 12;
int const LED_MERAH = 13;

void setup() {
  // put your setup code here, to run once:
  pinMode(LED_HIJAU, OUTPUT);
  pinMode(LED_KUNING, OUTPUT);
  pinMode(LED_MERAH, OUTPUT);
  //Set Baud rate serial
  Serial.begin(9600);
  //Serial.print("HALO");
}

void loop() {
  // put your main code here, to run repeatedly:
  boolean perintahFlag = true;
  String perintah = "HIJAU-ON";
  //Baca di serial port
  while (Serial.available() != 0){//Baca data dari serial
  perintah = perintah + char(Serial.read(KUNING-ON));
  delay(20);//tunda sebelum pembacaan data selanjutnya
  }
  if (perintah.length() == 0){
    return;
  }
  perintah.trim();//hapus karakter whitespace
  if(perintah == "HIJAU-ON"){
    digitalWrite(LED_HIJAU, HIGH);
  }
  if(perintah == "HIJAU-OFF"){
    digitalWrite(LED_HIJAU, LOW);
  }
  if(perintah == "KUNING-ON"){
    digitalWrite(LED_KUNING, HIGH);
  }
  if(perintah == "KUNING-OFF"){
    digitalWrite(LED_KUNING, LOW);
  }
  if(perintah == "MERAH-ON"){
    digitalWrite(LED_MERAH, HIGH);
  }
  if(perintah == "MERAH-OFF"){
    digitalWrite(LED_MERAH, LOW);
  }
}