The controller is basically a testing tool that I use for Parola/MD_MAX72xx where I need a few buttons and/or an analog value. There is not much to this ‘controller’. Making it is really straightforward as it is just connections between pins and switches, header, etc. Nothing unusual.
The Arduino shield has six momentary tact switches connected to D4 through D9 and one 10kΩ pot connected to A5. Pull up resistors are internal to the Arduino CPU by specifying the INPUT_PULLUP setting. All the software examples for this library and Parola use these inputs in a consistent manner.
The outputs for the matrix displays come out to a 5 pin header. I have them permanently wired to the Arduino hardware SPI interface (D10 SS, D11 MOSI and D13 SCK for the Uno board), GND and +5V.
In the photos you can also see that I created short perfboard ‘bridges’ for labeling the buttons. This is just simply because I can never remember what the buttons do!