Wednesday, 1 April 2009

Common ground Mod with analog switch

This common ground mod are uses in arcade stick building for several reasons:

- keep the wiring easy (daisy chain for ground)
- dual PCB mod
- using the standard 5 pin connectors for sticks like sanwa jlf and seimitsu LS32-02
- connecting vintage joysticks like competition pro for sensible soccer ;)

This is just another approach comparing to the optocoppler approach. Optocoppler a little bit more expensive. Therefore wiring is here mor complex and more parts are used.

Layout Description:

Joystick in general have the states disconnected (undefined) and active low. To define a active high for the inverter pull-up resistors (R1 - R4) are used when stick is disconnected.

When joystick is moved to one direction signal is active low. Inverter changes it to active high. Active High is needed because 4066 switches only on Active High. The output pins are enabled and activate corresponding button on the xbox360 gamepad.


Ki-tat said...

Hi bencao. For this switch, your sketch shows [direction]_1 and [direction]_2. Which is signal, and which is the local ground? I assume 1 is signal and 2 is ground?

bencao74 said...

doesn't matter. The 4066 is a switch. You've a electrical link between [direction]_1 and [direction]_2 wenn triggered.

Ki-tat said...

Ooh, right. Awesome. =P
Another question: I'm planning on doing dual PCB, will having 5V hooked up directly to the stick have any affect to the other controller?
Thanks so much for such a quick response. =]

bencao74 said...

;) no prob.

No, you can just hook up the USB 5V (i suppose) to the 3.3V PSX PCB...

don't forget the GND and the diodes for the Triggers (xbox360)

Ki-tat said...

Cool. Yeah, I'm soldering to a Dreamcast joystick, and my friend wants to keep the Dreamcast PCB. So is that 5V to the other PCB only, or 5V to the joystick/7404 as well as the other PCB?

I take it that it's exactly the same process for the buttons?

I'm not removing/hooking up the triggers, so it's less work =]

bencao74 said...

connect all the 5V / VSS to each other:

- other PCB
- 5V for 7404 mod

You don't need this mod, when the buttons are cg... What other pcb are you using?

Ki-tat said...

Sorry, I guess I wasn't clear. I'm soldering a non-common ground X360 controller (same one as you I think) to a common ground DC controller. Thanks alot, you've been a great help! =]

Ki-tat said...

Hey, I drew something up, and posted it on Shoryuken. Could you let me know what you think?