HELP Hacking USB Gamepad

[bsktbllmn23]

I am officially starting my cab build! Wanted to get the CP done first, so I decided I would try my hand at a gamepad hack.

Here are some pics, I have read a lot of different how to's but I have not seen anything quite like these. They have 1 USB connector, but 2 Gamepads attached. Controller 2's cord goes into the Controller 1, and then out to USB.

It shows up in Windows as a "Dual USB Gamepad" and works just fine in Mame and my other emulators. I just dont know if you all can tell what might be different when trying to solder these into my buttons and joysticks.

I have read about some gamepads NOT having 1 common ground. From what my very limited knowledge can tell me, this is one of those that DOESNT have a single common ground, as some of the contacts seem to have a different trace for ground... but again, I am very early in this process and could be wrong.

Thanks in advance for any help. 

[CoryBee]

That is definitely a unique controller, and corresponding PCB. All of the chinese gamepads I have use "special" ground like you speak of for the "up" & "right". The rest of the buttons use the common ground. It should be as simple as soldering wires onto those little silver pads and touching it to the common ground to see if it produces a proper button press. I bet though that it will only be the directional pad that has a "special" ground. If I am right then the "Up" button will show up as "down" . Also "right" will be "left". I go over my findings in my bartop arcades build in my signature.

After typing that I found my post on it.

I found that if i connect the common ground to the Right button pad it would register a Left button press. Same with Up, it would produce a Down button press. Bothered the ---steaming pile of meadow muffin--- out of me. So I just scraped off some of the board off where the ground is that they share and soldered my own pad for the "secret ground". I haven't the slightest reason why, I have guesses but not sure at all. If someone knows please inform me of this.

[bsktbllmn23]

1. You are absolutely right!
2. Your build is awesome, and I've been watching it closely to learn.

I have my multimeter out, and I guess I just don't understand how to read what I'm getting, or at least how it corresponds to how I'm going to gave to wire this pcb.

I will look back at your post and see what I can learn from the wiring part, thanks Cory

[CoryBee]

Well there's your problem. A multimeter is USELESS for testing a gamepad. 

Also, thank you for the compliment. I really liked how my work turned out with barely any tools or woodworking skills.

All you need to test a button press is to touch one wire from the little pad that corresponds to a button and the common ground. I go pretty in depth on my two build logs, the punch out and goku ones about that damn "secret" ground 

I was thinking about making a video about this issue as well, these controllers I buy are only $3.75 a piece. They have 14 buttons (including the directional pad) so they are very useful when you don't want to drop more than 10 dollars on 2 controllers for mame. 

Anyways, good luck with your weird dual gamepad controller(s)   

[bsktbllmn23]

Excuse my ignorance, but I'm still learning.

If I touch a wire to the "ground" labeled in the picture, and touch corresponding pads... And id they come up in control panel correctly, this is a common ground.

And I will have a second one for the ridiculous up and right buttons...

[capsule]

Well there's your problem. A multimeter is USELESS for testing a gamepad. 

Not if you want to test if the ground you've found is really "common" or not

[Blanka]

Just wire the buttons as they are wired on the pad, and there should be no problem at all.

[CoryBee]

Well there's your problem. A multimeter is USELESS for testing a gamepad. 

Not if you want to test if the ground you've found is really "common" or not

Sorry, you are right with that. You can use the continuity setting to check where the common ground goes from the usb.

Just wire the buttons as they are wired on the pad, and there should be no problem at all.

This is an option too, I did this at first and it is such a pain to have to solder two wires per button. Especially for 2 controllers. Here is a shot of my control panel on my first bartop.



Even with twisting the wires it was a bit of a mess. Plus having to scrape at some of the contact on the right side of each button to get a proper solder spot is too much of a pain for me to do again.

[bsktbllmn23]

I'm definitely going to go the route that you did Cory.

I don't really want to try and solder 2 wires for each contact.

I should have time this weekend to try it out. More pics to come!

[capsule]

I don't really want to try and solder 2 wires for each contact.

Definitely the way to go, use as many common grounds as possibles.
If you have a Dremel, drill the PCB to get "real" soldering points, it's much more durable and easy to solder.
You can also desolder the back buttons PCBs and use those predrilled soldering points (this is great to get a ground as well).

[CoryBee]

I don't really want to try and solder 2 wires for each contact.

Definitely the way to go, use as many common grounds as possibles.
If you have a Dremel, drill the PCB to get "real" soldering points, it's much more durable and easy to solder.
You can also desolder the back buttons PCBs and use those predrilled soldering points (this is great to get a ground as well).

I tried to drill through the contact pads on my most recent bartop dock build and had an issue. My drill bit was too big, even my smallest one drilled out too much pad that I couldn't get a proper solder connection. I should pick up a smaller bit sometime soon.

[bsktbllmn23]

I was going to use my Dremel and go get the smallest bit I could find. Trying to match it with the holes that are exposed on the PCB for the shoulder buttons. I might even try to use the ground on the Right Shoulder button PCB because it seems to be common to all the buttons except for the super-secret-willy-nilly-ridiculous ground that shares Up and Right.

I hooked them up last night and I seem to have an issue with how they are recognized in XP. They come up in the game pad dashboard as 2 separate controllers, but BOTH called "Twin USB Game pad".

Mala worked great. Mame didn't seem to be able to distinguish the difference between the 2 separate button pushes. I will be doing a ton more testing tonight after work and this weekend. So more details to come, but I am hoping that I was just really tired and that is the root of the issue haha.