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Swept RF Tagging Project

This project has developed a 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 resonance 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 graphical/musical application to demonstrate the system using one coil, tagging over 11 different objects and tracking their proximity and state to launch or modify musical sounds and graphics. Furthermore, work on a six-coil version of this project is in progress in order to enable gathering of three-dimensional position and rotation information of tags.

Joe Paradiso

Kai-yuh Hsiao


Link here for a website (2000) with more technical detail on this project

Link here for an older website (1999) that shows the project in evolution

Link here for a 1995 demo of the second prototype reader with a LEGO set

Link here to see a photo of the latest (2000) reader board in action

Link here for other related tag projects

Video Clips:

Demo video of the original musical tags system (17MB, 1:44)

John Zorn (who inspired the Trinkets interaction design with his early improvisation pieces) playing with the Trinkets system when visiting the Media Lab in April 2004 (15MB, 0:47)

Some Quicktime excerpts of Musical Trinkets at SIGGRAPH 2000 in New Orleans (31.5MB, 4:14)

A large MPEG of the pre-SIGGRAPH graphics/music demo (94MB, 3:51)

A smaller MPEG of the Pre-SIGGRAPH graphics/music demo (9MB, 1:48)

Papers on this system:

Electromagnetic Tagging for Electronic Music Interfaces, Paradiso, J.A., Pardue, L.S., Hsiao, K, Benbasat, A.,Y., to appear in the Journal of New Music Research, December 2003.

Tangible Music Interfaces Using Passive Magnetic Tags Joseph A. Paradiso, Kai-yuh Hsiao, and Ari Benbasat, ACM CHI 2001 Conference - Special Workshop on New Interfaces for Musical Expression. 

Sensor Systems for Interactive Surfaces. J. Paradiso, K. Hsiao, J. Strickon, J. Lifton, and A. Adler, IBM Systems Journal, Volume 39, Nos. 3 & 4, October 2000, pp. 892-914. 

Musical Trinkets: New Pieces to Play, J. Paradiso, K. Hsiao, A. Benbasat, in SIGGRAPH 2000 Conference Abstracts and Applications, ACM Press, NY, July 2000, p. 90. 

A New Continuous Multimodal Musical Controller Using Wireless Magnetic Tags K. Hsiao and J. Paradiso, Proc. of the 1999 International Computer Music Conference, October 1999, pp. 24-27. 

Swept Frequency, Magnetically-Coupled Resonant Tags for Realtime, Continuous, Multiparameter Control J. Paradiso and K. Hsiao, Human Factors in Computing Systems; CHI99 Extended Abstracts, 1999, pp. 212-213. 

Kai-yuh Hsiao -- Fast Multi-Axis Tracking of Magnetically-Resonant Passive Tags: Methods and Applications, M.Eng. Thesis, MIT EECS Department and MIT Media Lab, February 2001.

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Last updated November, 2003