Bonnie Eisenman bio photo

Bonnie Eisenman

Software engineer, author, knitter, Esperantist. Member of NYC Resistor and author of Learning React Native.

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I’ve really enjoyed Jeff Snyder’s class, COS/MUS 314: Electronic Music. For our final project, we were able to do whatever we wanted, so I decided to make + perform with my very own custom musical instrument.

Enter the Illumaphone, a light-based/spatial musical instrument that you can play by waving your arms around. It’s made from six stolen coffee cups, each of which sounds a different pitch. Light levels determine volume and vibrato. Here, watch the video.

Interacting with the Illumaphone

Wave your hands over the air to trigger a note. Fun! :)

More details: it calibrates to ambient light levels on startup, so you can light it dramatically as I did for our final performance, or just use it in any space. Lots of evenly distributed light will gives a better range of motion.

Light levels determine volume and vibrato, and each cup is keyed to a different pitch.

The build


  • 6 photoresistors (light sensors, super cheap, I adore them)
  • 1 Arduino Uno
  • The usual wiring bits: alligator clips / jumper cables / breadboards. I didn’t solder anything b/c it was a temporary sort of project.
  • Cardboard lid to a box of printer paper, to hide the wiring
  • 6 disposable coffee cups, to act as light-funnels
  • 1 laptop, to process data + do sound generation

Everything starts with six trusty photoresistors, one in the bottom of each cup. (Can you tell that I love photoresistors?) The Arduino Uno reads in data from the light sensors, and sends it to the laptop, which then uses ChucK (a musical programming language developed at Princeton) to synthesize notes as appropriate.

The physical build is key to providing a good experience. Hiding wires makes people focus on the sound, and the cups act as awesome light funnels, so their shape does kind of matter.

The prototype version sounds a little different, but most notable is that because I was testing in a place with more diffuse light, the range of motion was much greater. See this video:

Now for some more photos!

The bottom is a mess, but nobody can see it!

Add some black tape, plus some dramatic lighting, and the cups look much spiffier.


I really want to keep experimenting with making my own instruments. There’s something really satisfying about it! And yes, next time I will try to make my circuits less hideous-looking. In the meantime, I made a GIF…