Sensor Chair
The Sensor Chair was
designed in Fall 1994 for a new mini-opera, Media/Medium, that Tod
Machover composed for magicians Penn & Teller. The trick starts with a
performance by Penn on this new "magical" instrument. In the show, after
performing this "sensor solo," Penn explains how it works to the audience, and
then explains how such technology would have been very useful 100 years ago to
measure such invisible and ineffable things as ghosts and spirits. This leads
to a wild exploration, through music and magic, of the fine line between
state-of-the-art technology and "magic," and between the performance bravura of
entertainment and the cynical fakery of mystics and mediums. A rather large
team worked on the project, including Pete Rice and Eran Egozy for software,
and Joe Paradiso, Neil Gershenfeld and Ed Hammond for hardware. The person seated in the
chair becomes an extension of a transmitting antenna placed in the chair
cushion. antenna; and their body acts as a conductor which is capacitively
coupled into the transmitter plate. Four receiving antennas are mounted at the
vertices of a square, on poles placed in front of the chair. These pickups
receive the transmitted signal with a strength that is determined by the
capacitance between the performer's body and the sensor antenna. As the seated
performer moves his hand forward, the intensities of these signals are thus a
function of the distances between the hand and corresponding pickups. The
pickup signal strengths are digitized and sent to a Macintosh computer, which
estimates the hand position. A pair of pickup antennas are also mounted on the
floor of the chair platform, and are used to similarly measure the proximity of
left and right feet, providing a set of pedal controllers. Therefore, all
movements of the arms and upper body are measured very accurately, and turned
into different kinds of music depending on the state of the Hyperlisp
software.
[Jpeg of Sensor Chair]
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