In this NIME (New Interfaces for Musical Expression) peformance in 2008, Tom Gerhardt makes music from spinning plates.
Here’s how the piece works:
On the bottom of each plate there is a small white plastic disc glued to the center. On the disc there is a grove in the center, one magnet strategically placed, and five sections that can be colored black or left white. The magnet is used in conjunction with a reed switch to track rotational frequency, and the black and white sections are used as a binary rotary encoded via a black/white sensor.
With the combination of the B/W sensor and the reed switch, I am able to get accurate IDs (5 digit byte) and rotational speed serially out of an Arduino. That data is sent to the computer and fed into PD where it controls playback speed of a granulated loop.
Here, Gerhardt explains the genesis of the piece:
For some reason plate spinning got into my head as my method of performance. There is something really physical and chaotic with plate spinning that is like a magic show. Never do I get nervous when watching a guitar player on stage… mistakes do not seem as eminent or catastrophic—and that is an interesting aspect to bring to the stage, catastrophe.
After thinking about the music I want to create and plate spinning, I decided I would focus on that moment when the plate loses critical momentum, goes wobbly, and falls. What would it be like to have a sample tied to that organic decay? Through extending that ‘organic decay’ concept I think I can create a couple contraptions that use forces and breakdown of those forces to control the playback of samples, probably with granular synthesis.
It is also important for me to make sure the audience clearly sees the connection between an individual sample’s playback and the entropy of an object, i.e. be sure that I am not faking it with switches and whatnot.