// debounce GPIO input
void getPin(gpio_num_t pin, bool* state, const unsigned long dur) {
  unsigned long cur = millis() / 1000;
  static unsigned long lastRead = 0;
  static unsigned long lastHigh = 0;
  static unsigned long lastLow = 0;
  static bool high = false;
  static bool low = false;
  if (cur == lastRead) {
    return;
  }
  else {
    lastRead = cur;
  }

  if (digitalRead(pin) == HIGH) {
    if (!high) {
      lastHigh = cur;
      high = true;
    }
    if ((cur - lastHigh) > dur) {
      *state = true;
      low = false;
    }
  }
  else {
    if (!low) {
      lastLow = cur;
      low = true;
    }
    if ((cur - lastLow) > dur) {
      *state = false;
      high = false;
    }
  }
}

// usage
void loop() {
  getPin(PIN, &state, 5);
  if (state) {
    // do something
  }
}