Swept-frequency, magnetically-coupled resonant tags for realtime, continuous, multiparameter control

ABSTRACT

We have developed a passive tag reader optimized for applications in human-computer interaction. It sweeps through a 50-300 kHz read frequency, flagging any magnetically-coupled resonators in that range. It is a minimally-complicated circuit, and is able to provide the center frequency, resonance width, and amplitude for each detected tag over a serial line at 30 Hz continuous updates. The tags are easily fashioned, consisting only of an inductor and capacitor or magnetostrictor tag cut to appropriate length. We have written an engaging musical application to demonstrate this system, tagging over 11 different objects and tracking their proximity and state, launching or modifying musical sounds in accordance.

REFERENCES

• 1: Hiroshi Ishii , Brygg Ullmer, Tangible bits: towards seamless interfaces between people, bits and atoms, Proceedings of the SIGCHI conference on Human factors in computing systems, p.234-241, March 22-27, 1997, Atlanta, Georgia, United States [doi>10.1145/258549.258715]
• 2: See: http://www.sensormatic.com/html/easum.htm.
• 3: Spillman, W. B. Jr., Durkee, S., Kuhns, W. W. Remotely Interrogated Sensor Electronics (RISE) for Smart Structures Applications, in Proc. of the SPIE, Vol. 2361, 1994, pp. 282-284.
• 4: Lichtblau, G. J. Resonant Tag and Deactivator for use in Electronic Security System, US Patent No. 4,498,076, Feb. 5, 1985.

INDEX TERMS

Keywords:
RFID, finger tracking, musical interfaces, passive tags, proximity sensing, wireless sensing