Last Sunday, a number of MakNet members joined me in attending a musical circuits workshop hosted by BeAM (Be A Maker) and EMSG (Experimental Music Study Group) in by the Kenan Science Library at UNC. I walked into the room with my friend Drew, who was visiting for the weekend, and was immediately struck by the diversity in age of the audience. Many of the participants were undergrads, sure, but only about half; the rest looked like graduate students, with some older professors and members of the surrounding community interspersed.
In front of each person was a suspicious brown paper bag. We were informed that inside the bag were the rudiments of musical synthesis, and that in just a few minutes we’d have assembled our own take-home instrument. After a simple introduction, we were set to work building our circuits. Before long, the chirping of piezo-speakers rose up like a chorus of tireless crickets. The instruments were operated via a button (to supply power) and a potentiometer (for tuning). The fundamental pitch of the instrument could be changed by altering the value of a capacitor.
Things really got interesting when we swapped our potentiometers out for photoresistors; by casting a shadow on the circuit, we could now change the pitch! The piezo-crickets transformed into whistling birds.
For his final trick, our presenter handed out some pencils and wire. By attaching the wire to the graphite lead, we could generate pitches based on the resistivity of shapes drawn on paper.