void setup() {
  //
  Serial.begin(115200);
  if(!Serial) Serial.println("serial is not ok");
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
}

void loop() {
  //
  digitalWrite(5, HIGH);
  Serial.println("LAMPU MERAH ON");
  delay(1000);
  digitalWrite(5, LOW);
  Serial.println("LAMPU MERAH OFF");
  digitalWrite(4, HIGH);
  Serial.println("LAMPU KUNING ON");
  delay(1000);
  digitalWrite(4, LOW);
  Serial.println("LAMPU KUNING OFF");
  digitalWrite(3, HIGH);
  Serial.println("LAMPU HIJAU ON");
  delay(1000);
  digitalWrite(3, LOW);
  Serial.println("LAMPU HIJAU OFF");
  digitalWrite(4, HIGH);
  Serial.println("LAMPU KUNING ON");
  delay(1000);
  digitalWrite(4, LOW);
  Serial.println("LAMPU KUNING OFF");
}