CD-Synth: a Rotating, Untethered, Digital Synthesizer

We describe the design of 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. This paper discusses the design of the system, including the circuit, mechanics, and software layout, as well as how this device may be incorporated into a performance.