const int lampuIjo = 8;
const int lampuMerah = 7;

void setup() {
  // put your setup code here, to run once:
  pinMode(lampuIjo, OUTPUT);
  pinMode(lampuMerah, OUTPUT);

  Serial.println(lampuIjo);

}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(lampuIjo, HIGH);
digitalWrite(lampuMerah, LOW);
delay(500);
digitalWrite(lampuIjo, LOW);
digitalWrite(lampuMerah, HIGH);
delay(500);
}