Riley Blair, Stephen Fanning, Justin Kyi, Eli Hoffberg – C23 HUA 3910
Inspired by the behavior of a rapidly toggled electromagnetic solenoid, The CUBE offers a synth like timbre with an innocuous appearance (if you ignore the microphones of course). The underlying mechanisms are hidden within the box resonator, and held up by a 3D-printed housing. Although we pivoted from our initial designs with a suspended membrane and percussive capabilities, we proved that the process of systematically oscillating a permanent magnet affixed to a resonator produces deterministic and controllable vibrations with the capacity to create music.
Functionality
The final design of The CUBE involves a neodymium cube placed on top of a polystyrene box resonator, with an electromagnet and supporting circuitry inside as shown in the photo above. MIDI instructions are sent from the host computer to the Arduino via serial communication, which the Arduino code can then interpret. These MIDI serial messages are composed of two bytes of information: the first representing pitch, and the second, velocity.
To control the pitch of the note played, the Arduino sends a square wave signal to the H-bridge via PIN 1 and PIN 2, oscillating at the desired notes frequency. The signals to the H-bridge switch the direction that current flows through the electromagnet, swapping the polarity of the generated magnetic field, and changing the permanent magnet’s reaction force to either attractive or repulsive. These oscillations then induce vibrations in the attached resonator with a frequency equal to the input signal, producing sound at the desired pitch.
Final Composition
Below is a short composition in E minor showing off our two modules. The polyphonic tune was inspired by our groups interest in electronic music mixed with some of our classically trained compositional skills. In our demonstration of the device, we were able to produce a musical line that simulated multiple voices in one module; emulating styles such as chiptune and synth-pop. The final CUBE was successfully able to play a wide range of notes (around 3 octaves from C1-C4) at a reasonable volume, and switch between tones quickly.
Paper