Tuesday, June 14, 2005

MAME cabinet: panel prototyping

Based on the plans here, which I'm using as a starting point, I made a layout in Visio of a 48x19 control panel.

I used information from Ultimarc's website to make sure I had the sizes of all the parts correct. The Ultimarc buttons need a 1 1/8" diameter hole, while the actual surface area occupied by the button and the plastic surround is 1 5/16". Holding an imaginary joystick in one hand and resting my fingers on the kitchen table, I decided that 1 1/2" center-to-center made for good button spacing.

I've also planned for a spinner, even though I haven't ordered one. The Optipac board can interface with one, so I left space for it above the trackball. The trackball buttons will double as the spinner buttons. I like the look of the Vortex spinners from Oscar Controls, so I made plans for an appropriately-sized hole, with a view to ordering a spinner "some day".

By the time I finished the Visio work, my parts had arrived, and sure enough, no duty or taxes to pay. Nice. I hauled them all out of the box and tried out the buttons and the joysticks, but after that, they sat around for a few days.

I cut out a 48x19 piece of 5/8" plywood to use for the panel, but I wanted to prototype things before starting to cut into it.

So I made a double-layered cardboard template out of some old boxes in the basement, and pencilled in the locations for all the components.

Then, I cut out all the holes, and installed the parts. It's far from elegant-looking, but gives a really good idea of how the whole thing goes together.

Prototype control panel
The prototype control panel (click to enlarge)

I used the Neo-geo colour layout for the buttons, and tried everything out to get a good feel for the joystick. I want to top-mount the joystick, if possible, to get the extra height. I tried the joystick mounted from below (along with a 1/2" offset to account for the thickness of the plywood versus the cardboard), but it was just too low.

Button layout detail
Button layout detail (click to enlarge)

So everything seems pretty good. The distance between the two joysticks is a bit large to comfortably play Total Carnage, Robotron or Battlezone, but I figure the firing for those games can always be mapped to buttons. I'm not a purist, and because I've only got two joysticks anyway, two-player Total Carnage is going to require firing via the buttons.

With the prototyping done, the next step is to start cutting holes in my piece of plywood...

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