Tamagoshi w/ Arduino

const byte BT[] = {13, 12, 11, 10};
const unsigned long TEMPO[] = {1000, 2000, 3000, 4000};
const String STATUS[] = {"FOME", "SONO", "IRRITADO", "DOENTE"};

void setup () {

  for (byte i = 0; i < 4; i++) {
    pinMode(BT[i], OUTPUT);
  }

  Serial.begin (9600);
}

void loop () {
  unsigned long tatual = millis ();
  static unsigned long t0[] = {0, 0, 0, 0};

  static byte i = 0;
  if (i >= 4) i = 0;

  if (digitalRead(BT[i])) {
    Serial.println("NORMAL");
    t0[i] = tatual;
  } else if (tatual - t0[i] >= TEMPO[i]) {
    Serial.println(STATUS[i]);
  }
  i++;
}