Is it music? Noise? Inter-species communication? In a word: Yes.
The Slugophone is a musical instrument that’s playable by anyone—even a slug. But whether you’re an insect or not, there are many ways to interact with this electronic square-wave synthesizer: You can play it like a Theremin, making eerie tones via the motion of your hand; you can grab your friends, grasp the probes, and engage in some harmonious hand-holding (or melodic thumb wars); or, relax and let a musically-inclined caterpillar make sounds as it strolls across a copper grid. The instrument is packaged in a snazzy steampunk-style case—and, of course, it comes with an elegant portable terrarium to house the obliging caterpillars.
Our development of the Slugophone began with a notion to build a gadget called “Drawdio,” a simple synthesizer attached to a pencil. This device uses the conductive properties of pencil graphite to create different sounds as you move the pencil point across the paper. We tried it out, but in the end, we weren’t satisfied with how it worked. But as we were thinking of other things we could do with a similar circuit, the Slugophone was born. My dad talks more about the circuit here.
When the basic circuit build was done, we tested it out on some live slugs to see how it worked. We also grabbed a worm and a caterpillar. The slug, unfortunately, was quite slimy (and very conductive!) It made irritating, shrill music—and worst of all, it seemed to be distressed by the copper of the circuit board; the worm produced similar results. The caterpillar, however, made the most pleasant music, and didn’t seem to mind walking around on the circuit board. So for the rest of the project, no slugs were used. The name, however, stuck.
The Slugophone’s burnished metal case has a projecting speaker, a moveable Theremin sensor, and a series of knobs and switches on the front. These control volume, set the basic pitch range, and select input to the synthesizer: the photocell (Theremin) or the probes for humans, and the copper traces on the circuit board for insects. Here’s how it works:
The changing resistance value provided by an input device—probes, photocell, or copper grid—is transmitted to the proper pins of the 555 integrated circuit timer chip; this completes a circuit which produces different audible tones based on the resistance it’s given. For the Theremin, shading or uncovering the photocell provides the input; for the probes, it’s simply skin resistance. For the caterpillar, the changing resistance the insect’s body produced as it crawled across the copper board made new tones each time it moved.
The crowd at World Maker Faire 2011 seemed to enjoy the device as much as we did. Many people played with the photo-Theremin and the synthesizer until their friends dragged them away. Others spent long periods of time gazing at the monarch caterpillar crawling across the board (We actually had two, named Angel and Lucifer; they switched off regularly, and ate leaves in between shows. When the two-day event was over, they were released unharmed in the back yard.) All of the children wanted to touch the caterpillar, and many grown-ups were intrigued too. One spectator from a foreign country asked, in halting English, “So… caterpillar is DJ?” “Exactly,” we responded—proof that “music” can be made by anyone or anything…even a slug.