void setup() {
  Serial.begin(9600);
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  Serial.println("'on' untuk menyalakan");
}

void loop() {
  if (Serial.available()) {
    String perintah = Serial.readStringUntil('\n');
    if (perintah == "on") {
      while (true) {
        Serial.println("merah nyala");
        digitalWrite(2, HIGH);
        delay(1000);
        digitalWrite(2, LOW);
        Serial.println("merah mati");
        delay(100);

        Serial.println("hijau nyala");
        digitalWrite(3, HIGH);
        delay(1000);
        digitalWrite(3, LOW);
        Serial.println("hijau mati");
        delay(100);
        
        Serial.println("biru nyala");
        digitalWrite(4, HIGH);
        delay(1000);
        digitalWrite(4, LOW);
        Serial.println("biru mati");
        delay(100);
      }
    } 
  }
}