Controls

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Description

Build Control Box

The control box is cut out of the leftover 5/8" MDF from the cabinet construction.  Consult the design page for dimensions.  It is assembled in a similar fashion as the cabinet.  Ledgers cut out of the leftover 1x2's are attached to the side pieces by drilling through the panels with a #8 countersink bit, applying wood glue, and securing with #6 x 1 1/2" screws.  Note that the long dimension of the 1x2 is attached first.  The ledgers are attached with a 5/8" offset to ensure that all of the surfaces are flush.  The panels are clamped and allowed to dry before attaching them together.

The panels are attached together by drilling through with a #8 countersink bit, applying glue, and securing with #6 x 1 1/4" screws.  The whole assembly is clamped and allowed to dry.  The screw holes are filled with wood puddy and the whole box is sanded smooth.  I also rounded the corners for an added touch.

The keyboard door is cut out of the front panel.  One edge of the keyboard door is routed down by a 1/4" with a 1/4" router bit to accommodate the hinge.  A hole is made in the top of keyboard drawer to fit a cam lock.  The top of the front panel is routed down 1/4" for the hinge that will attach the control panel to the control box.

Cut Out and Drill Control Panel

The control is panel cut out of 5/8" MDF.  Consult the design page for dimensions.  Each of the joystick holes are cut with a 1 1/4" wood boring bit.  The button holes use a 1 1/8" bit.  Cutouts are also made for the trackball and spinner interfaces.  The corners are rounded off to a 1" radius.  A router with 1/16" slotting bit is used around the entire perimeter to make a groove for the T-molding to go in to.  Holes for the mounting bolts are drilled through with a 1/4" wood bit.

Cut Out and Drill Lexan

A sheet of Lexan is cut to the same shape and size as the top of the control panel except that the entire outside dimension is 1/8" smaller all around.  This provides a recess when the Lexan is mounted on the control panel so that the edge on the control panel is not sharp.  I used a 7" plastic cutting saw blade on my table saw to cut the basic shape.  The rounded corners and cutouts are made with a fine-toothed blade in a scroll saw.  Note that the spinner cutout is different than the cutout on the control panel and is instead a 1/2" hole instead of a square cutout.  The joystick and button holes were drilled with the same wood boring bits as the control panel.  Holes for the mounting bolts are drilled through with a 1/4" wood bit.

Lexan is worked in a similar fashion to wood except that the saw and drill speeds are a bit slower.  I would suggest practicing on spare pieces of Lexan before cutting the real thing.

Paint Control Panel and Box

The control panel and box use the same black latex semi-gloss paint as the cabinet.  I painted the control panel and box at the same time as the cabinet to save clean-up.  I also painted the exposed, underside edges of the control panel with a paint brush.  See the pictures below.

Add Contact Paper, Lexan, and Controls

I used marble contact paper for the top of the control panel.  The contact paper is applied by first peeling the backing off.  Start at one end and lay down the contact paper towards the other end.  Be careful not to get bubbles in the contact paper.  If you do, you can always pull the paper back and reapply.

Next, add the Lexan to the top and attach the controls.  The joysticks and spinner are attached with 10-24 x 2" black carriage bolts and secured with a black hex nut.

Wire Buttons

The buttons are wired so that one lead is attached to ground and the other lead goes to a terminal block.  The end of each lead that attaches to the controls is crimped to a .187 female spade terminal.  The other end is simply stripped and screwed into the terminal block.  Two 40 pin ribbon cables are wired onto the other side of the terminal block.  The end of the ribbon cable has a 40 pin female connector that will connect to the keyboard encoder.  

Wire Joysticks

The middle two joysticks and top-fire buttons are wired the same way as the buttons.  The outer two joysticks, P1 left and P2 right, are wired to a circuit I designed to allow me to select between 8-way, 4-way, and diagonal modes.  The circuit works via a switch mounted on the control panel.  When the switch is in 8-way mode, the signals that come from the joysticks pass through the circuit unaltered.  When the switch is in diagonal mode (i.e. Q-bert mode), a logical AND function is applied so that only the diagonals are registered.  When the switch is in 4-way mode, P2 right, which is a 4-way joystick, takes over the inputs from the P1 left joystick  The inputs normally received from P2 right are disabled.

Wire Trackball, Rotary Joysticks, and Spinner

The trackball, rotary joysticks, and spinner are wired to a circuit I designed that allows me to multiplex them to the KE-72T trackball input via a selector switch mounted on the control panel.  The circuit is quite simple and simply consists of a couple of 4 to 1 multiplexers and the selector switch.

Install Keyboard Drawer and Attach Control Panel

A piece of 5/8" MDF is used for the keyboard drawer and attached to keyboard slides with screws.  The slides are screwed to the bottom of the control box.  The slides were slightly longer than I had anticipated so I was forced to cut holes in the back of the control box to fit them (see photo).  Since the back of the control box is not exposed, it did not make any visible difference.

Install Keyboard Door

The keyboard door is attached to the control box with a 12" strip hinge.  I used the leftover hinge cut from the front cabinet door hinge.  A cam lock is inserted into the drilled hole in the keyboard door and a thin piece of wood is glued behind the front panel to give the tongue of the cam lock a snug fit.

Connect Keyboard and Encoder

Spacers are attached to the bottom of the Hagstrom KE72T keyboard encoder and it is placed inside the control box.  The two 40 pin ribbon cables are attached to the headers on the encoder and the keyboard is plugged into to the keyboard port.   A keyboard extender cable runs out of the control box to the PC.  The output of the trackball circuit is plugged into the trackball port on the encoder and a mouse extender cable runs out to the PC. 

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419.84

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149.90

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14.15

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25.91

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83.54