Audio Controller

Deej Description
“deej is an open-source hardware volume mixer for Windows and Linux PCs. It lets you use real-life sliders (like a DJ!) to seamlessly control the volumes of different apps (such as your music player, the game you're playing and your voice chat session) without having to stop what you're doing.”

Miodec Fork
Miodec's fork allows for the use of buttons with the deej software. The original deej software only allows for audio sliders. This fork allows you to assign a code to a button and that code translates to a particular key press. Im not an expert, so see the link at the bottom for more info.