int ledMerah = 8;
int ledKuning = 9;
int ledHijau = 10;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(ledMerah, OUTPUT);
  pinMode(ledKuning, OUTPUT);
  pinMode(ledHijau, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(ledMerah, HIGH);
  digitalWrite(ledKuning, LOW);
  digitalWrite(ledHijau, LOW);
  Serial.println("merah menyala");
  delay(3000);
  digitalWrite(ledMerah, LOW);
  digitalWrite(ledKuning, HIGH);
  digitalWrite(ledHijau, LOW);
  Serial.println("kuning menyala");
  delay(1000);
  digitalWrite(ledMerah, LOW);
  digitalWrite(ledKuning, LOW);
  digitalWrite(ledHijau, HIGH);
  Serial.println("hijau menyala");
  delay(3000);

}