IMAGING
C
G
E
F
D
Fig. C: Measuring holes for mounting the servo assembly to the project box. Fig. D: Servo motor wires are
threaded down to the ServoCenter board underneath.
Fig. E: Motor connection to the ServoCenter; the board
can handle up to 16 motors. Fig. F: Finished assembly of
the MIDI cam unit. Fig. G: The MIDI cam system laptop
runs VVVV to control camera movements and process
live video feed.
Pan-Tilt MIDI Cam Unit
To make a nice, self-contained single camera unit
I enclosed the ServoCenter board in a project box
and attached the pan-tilt assembly on top. The
webcam connects to the laptop, the pan-tilt servos
connect to the ServoCenter, and the laptop connects
to the ServoCenter through a USB-MIDI interface.
On the laptop, VVVV runs 2 separate workflows at
once: one generates MIDI to control the servos, and
one processes the video input from the webcams.
I drilled the top of the box and used 1¼" standoffs
to attach the pan motor, which acts as the base of
the pan-tilt assembly (Figure C). Inside, I mounted
the ServoCenter board using 2" standoffs. The
servo wires are threaded through another hole in
top (Figure D), and holes in the side allow access
to the ServoCenter’s MIDI and power.
If your webcam has a stiff cord, a small servo
might have trouble pushing it around; if so, cut
away the insulation on the outside of the cord. Then
mount the webcam on top of the pan-tilt assembly.
I used a short ¼" bolt that threaded right into the
cam’s original mounting hole, but you could use any
method that securely attaches the camera.
To start running your MIDI cam, download and
install VVVV ( vvvv.org), Midi Yoke, and MIDI-OX
(both at midiox.com). Then download my script at
makezine.com/19/diycircuits_midicams.
Run the core VVVV app, then open the script and
see the embedded instructions, which explain how
to set it up to move your cams, as well as use some
other simple VJ functions to mix in images or videos.
VVVV is a graphical programming language that
lets you build applications by drawing “building
blocks,” and linking them together. It’s not your standard Windows program, so figuring it out takes a bit
of reading the Help and poking around. But once you
get the hang of it, it all makes sense; it has a logical,
schematic-like workflow, so if you’ve ever read or
drawn a circuit diagram, you should pick it up quickly.
If you have MIDI hardware, you can connect that
to your laptop and use it to control your cameras
through VVVV. Moving a physical knob or slider is
better than poking around with a screen and keyboard, especially if you’re performing live.
For project software and to see the MIDI cams in
action: makezine.com/19/diycircuits_midicams
By day, Josh Cardenas is a digital artist at ImageMovers
Digital, but his background in computer graphics has led
him into the VJ world. Witness his pixel-fu at visceralx.com.
132 Make: Volume 19
