#define BTN1 D2
#define BTN2 D3
#define BTN3 D4
#define BTN4 D5

#define LED_ROJO   D6
#define LED_VERDE  D7
#define LED_AZUL   D8

void setup() {
  pinMode(BTN1, INPUT_PULLUP);
  pinMode(BTN2, INPUT_PULLUP);
  pinMode(BTN3, INPUT_PULLUP);
  pinMode(BTN4, INPUT_PULLUP);

  pinMode(LED_ROJO,  OUTPUT);
  pinMode(LED_VERDE, OUTPUT);
  pinMode(LED_AZUL,  OUTPUT);
}

void controlLEDs(int valor) {
  int r = LOW, v = LOW, a = LOW;

  if (valor <= 3) {
    r = HIGH;
  } else if (valor <= 5) {
    v = HIGH;
  } else if (valor <= 7) {
    r = HIGH; v = HIGH;
  } else if (valor <= 11) {
    v = HIGH; a = HIGH;
  } else if (valor <= 14) {
    a = HIGH;
  } else {
    r = HIGH; v = HIGH; a = HIGH;
  }

  digitalWrite(LED_ROJO,  r);
  digitalWrite(LED_VERDE, v);
  digitalWrite(LED_AZUL,  a);
}

void loop() {
  int b0 = !digitalRead(BTN1);
  int b1 = !digitalRead(BTN2);
  int b2 = !digitalRead(BTN3);
  int b3 = !digitalRead(BTN4);

  int numeroFinal = (b3 * 8) + (b2 * 4) + (b1 * 2) + b0;

  controlLEDs(numeroFinal);

  delay(50);
}