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Wed 06 Sep 06 @ 8:21 am

My latest project (which forms part of my new console, see below) is a MIDI controller for VDJ. It's built into a 2u rack panel, and sits alongside the mixer and DAC-2 as a convenient way of accessing features such as hot cues, looping features and FX. In addition, there are also two fader controls, for video crossfading and FX adjustments.

The circuitry is based around an old MIDI keyboard which was surplus to requirements. It's fed with 12 volts taken from the PC's PSU, and the MIDI output goes via a MIDI to USB convertor into vdj.

The difficult task was working out how to wire pushbuttons to the panel instead of the original keys. The original keyboard consisted of two sets of carbon contacts for each key, organised into groups of 6, and wired together using a diode matrix. As I was only using single-pole pushbuttons, I added an extra bank of diodes to simulate double pole switching.


I took the pitch and modwheels from the keyboard and mounted them as-is to the new panel, although the pitch bend wheel was adapted - by removing the internal spring, it now acted as a normal fader rather than the spring-loaded left-centre-right action of a pitch bend.



The finished product - there's seperate controls for the left and right decks - the top row of buttons are for activating different loop lengths, below that are the hot cues and key lock, and below that are 4 FX buttons. The black buttons on the right select different video transitions and FX, and the video crossfader and parameter adjust fader can be seen on the extreme right of the panel. The red knob on the panel is not actually a MIDI device - it's a 4-way video switcher, so that during gigs I can easily select my video output from DVD/VDJ/camcorder etc. It just made sense to mount it there, next to the video crossfader.

Next job - a second 1U panel that will sit above it, (above the ZOOM fx unit) with a further 12 buttons for the sampler, and maybe another fader as well. The original MIDI keyboard, along with it's pitch bend and modulation wheels, also had a data entry fader, which you can see in the picture of the circuit board. Not quite sure what I'll use it for, but it's bound to have a use sooner or later!