int Hijau = 2;
  int Kuning = 6;
  int Merah = 7;
  int biru = 1;

void setup() {

  pinMode(biru, OUTPUT);
  pinMode(Merah, OUTPUT);
  pinMode(Kuning, OUTPUT);
  pinMode(Hijau, OUTPUT);

}

void loop() {
//lampu merah menyala 
digitalWrite(Merah, HIGH);
delay(1500);
digitalWrite(Merah, LOW);
delay(1000);

//lampu kuning menyala
digitalWrite(Kuning, HIGH);
delay(1500);
digitalWrite(Kuning, LOW);
delay(1000);


//lampu hijau menyala
digitalWrite(Hijau, HIGH);
delay(1500);
digitalWrite(Hijau, LOW);
delay(1000);

digitalWrite(biru, HIGH);
delay(1500);
digitalWrite(biru, LOW);
delay(1000);
}