Assembling

From a board of 16 mm in thickness, performing a 10 mm milling, and using a 3 mm MDF cover, we have only 7 mm in height to accommodate the PCBs, the wiring, the microcontroller board, etc. Fortunately I got copper boards as thin as 0.8 mm, half the usual.

I decide to use nylon fastening hardware, because it's easy to modify, to glue, etc.

And I proceed to place the four PCBs on the chessboard:

Now we install the jumpers, of tinned copper wire, converting the four PCBs into a single matrix:

The wiring is performed by following this scheme:

You can see more complete diagram variants here: Teensy Board

Finishing the assembly:

LED (flat head) used to indicate the Turn.

Wiring finished.

All the wiring flows into the Microcontroller.

The PROGRAM pushbutton actuator is installed flush, and the other two pushbuttons are installed protruding 1mm

Main cover installed.

Even with main cover installed, you can access the electronics.

Detail of LED in the "Player's side".

Detail of LED in the "Opponent's side".

Detail of the controls and the mini-USB connector.

Job done!