I bought a new keyboard to replace my 10 year old Logitech G15 and now I enjoy the use of a Logitech Pro TKL mechanical keyboard. It comes with individual programmable RGB (what doesn't these days) keys and several re-programmable function keys. Unfortunately I quickly discovered how badly I miss a feature that my old keyboard had and the new one doesn't (unless you set up macros or use function keys).
What I really miss is the volume wheel and easy access media control buttons. I took the opportunity to solve the problem by building my own USB peripheral device. This device provides the following functionality:
The controller consist out of the following hardware:
Arduino pro micro
RGB rotary encoder
4x 12mm momentary pushbuttons with white LED
Variety of resistors (pull-up and current limiting)