“It’s simple to make custom USB keyboard and mouse controllers.
I use a few keyboard shortcuts when rating pictures in Adobe Lightroom, and found that I can be even faster using a simple game controller joystick. I mocked it up on a breadboard with two components I already had in my workshop and found that it worked great, but it needed a nicer “cabinet” for it to live on my desk.
Because it is Arduino based, customizing the joystick functions and add additional buttons, dials, or other controls is easy.”