Tuesday, 8 October 2013

Classic Gaming Hardware mod - 001 - PSX Dualshock to Amiga CD32

Some may know of my enthusiasm for nearly all things Amiga, the Commodore Amiga, on which I began making digital artwork, or something approximating digital art anyway...  And it was also fun for games!  In the mid 90's Commodore released a games console called the CD32; basically one of their desktop machines stripped of its keyboard, with an additional custom chip and integrated into a games console form factor with integrated CD-ROM drive.  As single button joysticks just were so passé by '93, the machine also came with a proprietary Joypad, akin to the Sega 6-button or the SNES joypad.
Computing chaos in the retro-nook, the safety goggles do nothing, but were useful to store tiny screws...

All the extra buttons on these types of pads mean that the simple approach of treating every button as an individual switch, with an individual wire in the cable would be impractical. In order to prevent these pads from requiring lots of individual wires and massive connectors, the button presses are converted to digital signals and sent on a single wire.  This means that to convert one pad from one machine to another you need pre-programmed microchips to allow the pad to talk to its new host machine.

Fail to increase your understanding of this concept with this useless infographic I made.
Recently I bought a board from from a small retro-peripheral manufacturer called KMTech, which does just this, even better, it fits (with some modification) into an old PSX Dualshock controller, specifically the SCPH-1200.  Its designed to fit into a different type of pad, but I prefer the Dualshock, also helped I had a couple of examples of these already.
The 'Amipad' board, with Dualshock shoulder button boards installed.  The 2 microchips convert button presses into digital signals, which are decoded within the Amiga, meaning lots of buttons can send on/off signals on a single wire, swish!
I just had to make a couple of modifications, because the pad that this board is designed to go into is near identical, just a matter of testing for fit and removing what gets in the way - these are located entirely near the middle of the pad, 3 posts where the cable is normally wound for strain relief and some jutting bits of plastic near the cable exit.  On the lower shell the only part which needed modification is a support post, all these are shown in the image below.

upper and lower 'shells' of the controller.

The cruelly removed guts of the Dualshock pad. Lean closer "k kuh kill meeeeee" it seems to whisper... to the spares bucket with you!
 Anything that interferes with the position of the board, even by a couple of milimeters, must be removed, or the function of the buttons will be impaired, so it needed some tweaking to get it right.

The board should sit as flat as possible.

I could have re-installed the analogue board, though this leaves a couple of gaping holes in the pad, this might be a nice place to add some rotary switches for something.

Assembled with the analogues removed.
 But I decided to add some plastic covers, glued in place with some contact adhesive. I had to grind the plastic down on the pad to get a snug fit.
I haven't worked out a good solution for strain-relief on the cable yet, on the ami-pad the cable is secured to the analogue board (which means destroying the analogue board) so any suggestions welcome.  I should probably sand and paint the pad (perhaps a delightful retro yellow/brown:D) as its no longer going to work with anything Playstation related!

Playing the CD32 version of Benefactor (which needs all the extra buttons) on the Amiga 1200 computer.
As you can see in the above image, the buttons are now confusingly labelled and will have to be painted or some solution found.

Maybe one day I will design and 3d print my own shells and buttons!