Since being a VJ at coachella for the past couple years, I’ve become interested in finding new ways of controlling image media. I found this instructable that I’ve been wanting to mess around with a while back. It computes the hard drive disks speed and direction using a microcontroller and sends it as serial data to a computer. The computer translates this data into MIDI or OSC which can control audio and video in a variety of applications such as Max/MSP, Modul8, or VDMX.

The instructable uses a PIC microcontroller, but since Arduino is my current microcontroller of choice, it became a matter of porting the idea. Fortunately, Matt Gilbert had done most of the work for me.

I ended up creating my own version of the circuit, more similar to the one on the instructable rather than using his. I tried Matt’s circuit based on the diagram he provided, but for some reason wasn’t able to get it working. His code works pretty great though and is well commented.

Because I wanted to be able to use multiple controllers at once, I decided to use the LM324 Op Amp to amplify the signal coming from the hard drive. I hooked up the hard drive signals to an oscilliscope to see what I was getting. With the help of Eric Rosenthal I was able to get some good readings.

With some tinkering, I was able to figure out a circuit that gave me a pretty decent response to the movement of the hard drive.

I started working with Marko Manriquez to design a prototype for our controller. Marko found some nice slabs of plexi, so we decided to use those. He was able to take the hard drives disks completely out of their case and reassemble them. We added some LED to indicated the moment of the two disks and wrote a simple processing sketch to visualize the data being sent by the Arduino. I hope to have better schematics and Max patch sometime soon that makes use of our controller. Until then, enjoy this video!

posted on December 9th, 2009 at 8:44 PM