I made a portable MIDI controller, there are 4 operating modes in it, Keyboard(MIDI), DrumPad(MIDI), DJ(MIDI) and GamePad(HID-joystick).
The DJ mode is for Mixxx. I have done the mapping files and test it. Currently my job is add this mapping to Mixxx repo to native support it.
Mixxx Wiki: https://www.mixxx.org/wiki/doku.php/soundless_studio_joymidi
If there is any suggestions, plz let me know.