 /* 
 * TODO:
-* reset button (chronos style?) - P1
 * time setting - P1
 * case - P1
 * wiring diagram - P2 S3

    pressed_at(0),
    pin_number(pin_number_) {
    pinMode(pin_number, INPUT);
  };

  // returns the number of ms for which the button has been held down


      //serprintf("pressed_at=%lu, millis=%lu\r\n", pressed_at, millis());
      return millis()-pressed_at;
    } else if (pin_status == HIGH) {
      if (pressed)
        serprintf("PollButton::poll: released\r\n");
      pressed = false;
