1 Jun 2020, 17:56

Hi everybody! I'm new to this forum and this is my "housewarming offer".

Few years ago, when I build my arcade, I've left a small space for a Home Button in the center of the controller's box. It's a dedicated button would should return to Recalbox's games' select menu. However, since I needed to think about a circuit to isolate the Raspberry's +3.3v Start and Select pins (it's not possible just "join" both wires in a third button without loosing their individual functions), I decided to handle this implementation later.

This year, after a party (before the covid crisis ;D ), I decided that my arcade really needed a Home Button indeed. Not all guests knew that pressing Start + Select would return to initial menu (in fact it's not something really obvious for casual players).

So I decided to share with you this simple solution.
Project cost: <$2 USD+/- (in Brazilian Real something near R$6).

List of components:

  • 2 units - SPDT 5V relay;
  • 1 unit - 10k ohm resistor
  • 1 unit - 1N4007 diode or similar (in fact you may place one for each relay);
  • 1 unit - PNP transistor

About the List: I used components I already owned here; it's possible (and cheaper) to replace the relay components for a transistor-only scheme if you know electronics.

Desirable: a small universal pcb; it's also possible to fix the components over a cardbox or a wooden card (or whatever-solid you have there with you). The base is not so important since you mantain the components apart each other.

My setup:
Raspberry Pi 3 B+ with Recalbox; using (Player-1) controller's Start and Select (hotkey) to return to Home Screen; using the GPIO pins for Player 1 and Player 2; inside an arcade cabinet (built by myself). However, this circuit works for any kind of controller (if you need to shrink there is still the transistor-remodeling option I told before).

Schematics:
Botao-Home-Mamute-600x400_2020-05-31_19-26-44.png

VCC 5V: I'd rather using the Raspberry source instead of the 2/4 GPIO pins.

Tinkercad simulation:
https://www.tinkercad.com/things/9ap3I2M21ws

Video: Circuit I've build (functional) - PORTUGUESE
https://www.youtube.com/watch?v=FTBdr8fgu2A
PS.: terrible soldering abilities alert.

Video: Working proof: Home Button running during a game - PORTUGUESE
https://www.youtube.com/watch?v=1hJHnYA5F_Q

That's all folks.

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This post's translation was an idea of @Zing.

Original post (PORTUGUESE): https://forum.recalbox.com/topic/20851/projeto-botão-home-retorno-para-a-seleção-de-jogos