CHIMAERA The Poly-Magneto-Phonic Theremin An Expressive Touch-Less Hall-Effect Sensor Array

Portner, Hanspeter

Proceedings of the International Conference on New Interfaces for Musical Expression

The Chimaera is a touch-less, expressive, polyphonic and electronic music controller based on magnetic field sensing. An array of hall-effect sensors and their vicinity make up a continuous 2D interaction space. The sensors are excited with Neodymium magnets worn on fingers. The device continuously tracks position and vicinity of multiple present magnets along the sensor array to produce event signals accordingly. Apart from the two positional signals, an event also carries the magnetic field polarization, a unique identifier and group association. We like to think of it as a mixed analog/digital offspring of theremin and trautonium. These general-purpose event signals are transmitted and eventually translated into musical events according to custom mappings on a host system. With its touch-less control (no friction), high update rates (2-4kHz), its quasi-continuous spatial resolution and its low-latency (<1 ms), the Chimaera can react to most subtle motions instantaneously and allows for a highly dynamic and expressive play. Its open source design additionally gives the user all possibilities to further tune hardware and firmware to his or her needs. The Chimaera is network-oriented and configured with and communicated by OSC (Open Sound Control), which makes it straight-forward to integrate into any setup.