I recently got a new keyboard from Das Keyboard
and love it. However, one of the drawbacks is the lack of multimedia keys (volume, play, next song, etc...). I really didn't want to NOT use this keyboard, so I decided I'd make something to replace the lost functionality.
This is more of a story of what I did, rather than a full on how-to. Mistakes were made, tears were shed, but I got a very useful keypad out of the ordeal and I hope that this information might be useful to someone else.
Just as a disclaimer: The multimedia key functionality of the Teensy doesn't work in Windows for some reason. All of the rest of it does, just not the multimedia keys...