Electromagnetic Tagging for Electronic Music Interfaces

This paper describes the development of a musical interface based on electromagnetic tagging technology, where an ensemble of passively tagged objects is identified and tracked in real time when placed in the vicinity of a reader. As the system is able to identify and update the state of many (30 or more) tags simultaneously, they can be used together in any combination – e.g., several can sit on a surface at fixed distances from the reader while others can be handheld or worn by a single user or multiple performers. This interface is able to detect both free gesture (position and orientation of the objects) as well as local or tactile variables (e.g., pressure). We describe a series of controllers that exploit the musical possibilities of this architecture – the somewhat constrained Musical Trinkets, where objects were tied to simple notes and musical effects, and its successor, the Musical Navigatrics, which enabled dynamic overdubbing and control of complex musical sequences and sonic textures. We close with a description of a very simple and inexpensive actively-tagged tracking system capable of much wider range.