USB Gamepad hack

[remakes]

I'm a little new at building my own arcade controls, but what I would like to do is to hack a USB gamepad (like the Gravis Gamepad pro, USB).  Is this possible, and if so, how easy is it?  I am trying to go for a "cheap", yet easy to setup control panel.  I plan on using my computer for other things other than arcade, so I would like to maintain the use of my keyboard, and so I figured that rather than messing with a bunch of splitters, the gamepad hack would be the best way to go.  Any suggestions?

[MameFan]

Yes you can hack the Gravis USB GamePadPro.(I have personally done it a few times). However things to note:

1) *MOST* of the connections do NOT share a 'common' ground.  This means you have to run 2 wires to most buttons/joystick directions instead of just 1 and daisy chaining a single ground wire.  (Yes, the shoulder buttons each have a common ground, and I think a couple other ones do, but even those are isolated from each other. You're better off just running 2 wires anyway, lest you mix it up and/or fry it by crossing wires that shouldn't be)

2) The points to solder to are VERY VERY small.  You will ideally need to buy a small dremel like tool and the smallest drill bit you can find (ones made for dremmels, not regular drills)--one about the size of a large needle.  Very carefully drill thru the copper on the pad.    You can attempt to directly solder to the pad, rather than running the cable up through a hole in the bottom and then soldering, but the problem is you will be apt to tug away and rip the trace off the board by soldering parallel to the board rather than perpendicular through a hole.

All in all, I don't think I will do more USB game pad hacks.  Yes, the Gravis is a VERY good choice since it has 14 discrete, non-matrixing inputs and is USB (good and bad), and is low-cost ($15 or < from most places) but the trials of connecting to such small traces is not for the faint of heart.


BTW--I have a few boxes of unopened Gravis GamePad Pro USB's (the charcoal grey ones) left over.  If anyone wants them I'll sell them for $12.50 each plus shipping. (shipping of $4 for one,  plus $1 for each additional one)

[Gee, I should have HYPED them rather than giving the honest truth + and -, eh??? ]   But if you are good at soldering and want to save money over IPacs and whatnot, then yeah, gamepads work fine.

[remakes]

Thanks for the help!  My goal (obviously) is to spend as little money as possible, so I think the gamepad will be my best option.  Is there a good source to look for good information on this topic (diagrams, etc)?

[aj6500]

Walmart sells a USB pad for $10 that has 13 inputs, counting d-pad and start button.  It shares a common ground for all inputs and has small solder pads.  You don't really need a diagram.  Once you get a pad strip it down to the board and peel of the rubber buttons.  Under each little button you'll see some exposed copper tracing that mesh together, but don't make contact with each other.  Off of one side of the mesh will be a trace that connects to 1 side of every other input.  That is the common ground.  On the other side of the mesh will be a trace that leads to a chip mounted in the center of the pad.  This is the actual input side you need to wire to your buttons.

Definitely drill and solder to the small solder pads on each input.   It is very easy to pull the tracing otherwise.  Then run a wire from the common ground to the common side over every button you install.  Wire the switched side of each button to an input on the circuit board.  Once that's done your pc will see each button press as a connection just like the gamepad before you took it apart.  It's simple to do.  

Just make sure you install the gamepad on the pc and make sure it works with your software before you start.  If the software uses keyboard presses as an interface, you can get a program like Keyboard2mouse that will make it work.

[remakes]

Thanks for the additional information!  That would be plenty of buttons.  The Gravis gamepad actually has a few more than I need.  I plan on just going with the standard "Street Fighter" control panel with a start button an "insert coin" button.

[IceCold]

Anybody hacked the Gravis Gamepad Pro non USB version?  It looks the same, has the same amount of buttons, but is white and not USB.  This is what I'm planning on doing.  Actually, I'm going to hack 2 of them, 1 for each player(and there will be room for start buttons, coin buttons, etc.).  Another good thing is, they have like a splitter on the end of the connector, so you can hook up another joystick/gamepad to it.  That way, I can have 2 gravis gamepad pro's both hooked up, and have my whole control panel be working.

I hope they won't be TOO hard to hack!    I guess I'll know in a couple weeks  

[Zeitgeist]

The Gravis GP Pro Usb is definately the way to go for a serious multi button / single player stick.
You must use a decent soldering iron set at low temperature or you could lift the traces with the excessive heat.
My latest creation uses the GPPro.

[eightbit]

I know you want to go as cheap as you can but have you considered the keywiz from http://groovygamegear.com. The economy model is $27 and is almost as cheap as hacking 2 USB game pads and would offer you far more functionality and flexibility. If you mess up one of those pads when soldering it, it will end up costing more than just using a quality keyboard encoder interface to start with.

[remakes]

That's definately something to consider.  I'm still a little new at this, but if I went that route would I have to construct a splitter for my regular keyboard to maintain use of it?  I plan on using the computer for things other than arcade.  That is one of the reasons I was going with a gamepad hack.

[Kitbasher]

The USB gravis Game pad pro is a very easy pad to hack.  I just copied Gnateye and drilled little holes in the board and pushed the wires through the surface and layed it on the pads and soldiered one wire to every connection.  I used all the connections so I could use the stick with espxe to play a few playstation games I have as well as mame with it.  The reason I chose game pads, is so I can play two or one player by just plugging in another stick, or the second stick can be used on my wife's machine. It gives me flexibility.  Now if I was going to build a dedicated arcade machine I would definately go with a keywiz or an ipac.  Simply depends on what your goals are.  If its a one person desktop controller, I say hack a gravis game pad pro.  

[MameFan]

> Anybody hacked the Gravis Gamepad Pro non USB version

Be aware that unless you use the special Gravis drivers, you cannot cascade multiple ones of those together and have windows "see" the extra buttons.  I'm not sure how Mame handles it, but I remember the old flat ones were a pain to get Mame in the .31 to .33 days and Win9x to work right together with more than 1 control attached to the GamePort due to the limitations of windows and the Gameport design.

Before you start hacking, FULLY test your pair of gameport GGPPs to ensure they will work after all you work!

[IceCold]

> Anybody hacked the Gravis Gamepad Pro non USB version

Be aware that unless you use the special Gravis drivers, you cannot cascade multiple ones of those together and have windows "see" the extra buttons.  I'm not sure how Mame handles it, but I remember the old flat ones were a pain to get Mame in the .31 to .33 days and Win9x to work right together with more than 1 control attached to the GamePort due to the limitations of windows and the Gameport design.

Before you start hacking, FULLY test your pair of gameport GGPPs to ensure they will work after all you work!

Thank you for warning me about that!  I'll try testing them thoroughly once I get them, before I start hacking.  Hopefully by now they have better drivers for it or something like that.

[remakes]

That's another main reason I was going with a gamepad over a keyboard hack, is that it is VERY easy to swap in and out.  I also plan to use my computer for things like internet, word processor, etc., so I need full function of my keyboard, and I prefer not to mess with splitters to have access to both.