int merah = 10;
int kuning = 9;
int hijau = 8;
int buzzer = 7;

void setup() {
pinMode (merah, OUTPUT);
pinMode (kuning, OUTPUT);
pinMode (hijau, OUTPUT);
pinMode (buzzer, OUTPUT);

}

void loop() {
  digitalWrite(merah, HIGH);
  digitalWrite(kuning, LOW);
  digitalWrite(hijau, LOW);
  tone(buzzer, 262);
  delay(2000);
  noTone(buzzer);
  digitalWrite(buzzer, HIGH);
  delay(2000);

  digitalWrite(merah, LOW);
  digitalWrite(kuning, HIGH);
  digitalWrite(hijau, LOW);
  tone(buzzer,294 );
  delay(2000);

  digitalWrite(merah, LOW);
  digitalWrite(kuning, LOW);
  digitalWrite(hijau, HIGH);
  tone(buzzer, 330);
  delay(2000);

}