Instructables user fraganator writes:
Having a hardware interface to your favourite music / DJ / VJ software can really open up doors in your creativity. The most widespread form of hardware control to your PC for such applications is a MIDI based controller.
A MIDI controller can send and receive MIDI messages to your PC, allowing direct control of your software. Not only that, but the controls can generally be mapped to anything your like. So what might be a volume fader for one person can be an effect filter for another.
This article will describe how to build and program a custom arcade button MIDI controller, while trying to keep the price below $100. It is aimed at electronics and programming novices.