Rotational musical instrument interfaces are a very intuitive representation of the fundamentals of music itself, as they are inherently simple oscillators that can run from low control frequencies up to audio. The downside of many rotating instruments is that they are bounded by the rotating mechanisms themselves, that being a fixed axle where the rotation is driven by a hand or a motor. This leads to a reduction of the performer’s expressive ability to influence the generated sound by constraining them to fixed locations and/or positions. In this work, we avoid these drawbacks, but maintain the affordance of the rotational interface by incorporating non-contact sensing and wireless data transfer.
We designed an untethered digital synthesizer that can be held and manipulated while broadcasting audio data to a receiving off-the-shelf Bluetooth receiver. The synthesizer allows the user to freely rotate and reorient the instrument while exploiting non-contact light sensing for a truly expressive performance. The system consists of a suite of sensors that convert rotation, orientation, touch, and user proximity into various audio filters and effects operated on preset wave tables, while offering a persistence of vision display for input visualization.