Keyboard Box

Figure 8 — Keyboard box opened. The metal rectangle is the lid for the box, and has the keyboard's grounding wire screwed to it. The mess of wires connect the input and output pins of the keyboard IC to the D-type connector pins. The controller connector can be seen at top, covered in green electrical tape to prevent shorting once everything is crammed into the project case.

While it might take a while to do and may be frustrating, the keyboard box is conceptually pretty simple. Solder wires from the input and output connections on the IC board to the D-type connectors. I'll go into a little more detail however to help alleviate some possible pitfalls.

Step one is to cut some holes in the project case for the D-type connectors and for the keyboard port. A Dremel isn't very good for plastic, as it goes so fast that it tends to melt it. I just used a regular power drill instead. First, I marked off a rectangle large enough to accomodate the butt end of a D-type connector (make sure you use the opposite gendered connector from whatever the controller plug is!). The location of the ports isn't critical. Drill out the corners so that the holes lie within the rectangle you've drawn, then keep drilling along the lines of the rectangle (again, make sure the hole lies within the rectangle — don't drill on-center with the lines, because that would make the cutout too big). Use a small saw, craft knife, utility knife, or file to cut between the holes, and file down the edges until the D-type connector fits comfortably inside (the flange should not pass through the hole, just the butt end). With the connector in place, trace some cicles where the screw holes are. Remove the connector and drill small holes where you just traced for screwing the connector on. A keyboard cable hole can be made by cutting a little D-shaped archway close to the lip of the project case just slightly smaller than the diameter as the keyboard cable. It should be placed so that when the project case cover is attached it will allow enough room for the cable to fit tightly, but without crimping it or making it flop around.

You may need to desolder and remove the connectors on the keyboard IC board. If your keyboard had the two little sheets with circuitry on them which slipped into little slots on the IC board, you need to remove those slots so that just the holes on the board remain. That way you can insert and solder your own wires in there. You can do this without removing the connectors, but I'd recommend taking them out.

Figure 9 — Close-up of the keyboard IC board. The connectors were removed and the wires were soldered into the holes (from the other side of the board).

Cut some more wires. Lots of wires. You need one for each pin for each controller. I used a length of about 7–8" to give myself lots of room to work with. Run the wires through the connector holes you cut. Don't make the mistake I made of soldering the D-type connectors to the board without threading the wires through the housing holes first. I had to make the hole larger to fit the whole connector through, flange and all. Kind of a pain. You'll need to solder one wire from each input or output hole on the IC board to the appropriate D-type pins. Consult your wiring spreadsheet you made earlier. Be very vigilant about soldering your wires correctly. Nothing is more disappointing than spending hours doing tedious soldering only to find you did it all wrong. Do frequent tests with your continuity tester and by connecting the device to your computer. Solder the D-type connectors the same way as in the controller plugs, doing the middle row first, and hot gluing to add strength. When you're done, wrap all the metal areas of the connector and its wires with electrical tape. We're going to be cramming an IC board in there, and you don't want it brushing up against any of those metal parts causing a short. Put the connectors in their holes and screw them in place with some small nuts and bolts.

Figure 10 — A view of the male D-type connector screwed into the project case.

If your keyboard cable had a ground cable and your project housing has a metal cover, drill a small hole in your cover and screw the ground wire to the casing. This will help ground it. I don't really know what that means exactly, but I've heard it's a good idea.

By this point, all the circuitry should be in place. If you haven't tested it all yet, you might want to. Or just tuck the keyboard IC board into the project case (being careful not to stress any of the delicate wires or solderings and that no metal is touching the IC board). Place the keyboard cable into the cable hole and add a hot glue snot ball to the cable on the interior side so it doesn't pull out of the box. Screw the project case cover on, plug your controller into the connector, the keyboard connector into your computer, and you're set to go!

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