Stomping Ground is a permanent installation at the MIT Museum consisting of a musical carpet and a projection of live video with superimposed blobs. Kids seem to love it. It is a collaboration between Joe Paradiso of the Responsive Environments group, who made the carpet and the radars, Kai-yuh Hsiao of the Cognitive Machines group, who wrote the music, and Simon Greenwold of the Aesthetics + Computation group, who designed and programmed the visuals.

See a movie of Stomping Ground in action.
Responsive Environments' page about the carpet.
 

What it does
The carpet tracks the location and intensity of footfalls with a grid of sensors. Doppler radars mounted on the sides of the projection wall track the overall direction and intensity of upper-body motion. This information is used to create a musical composition that has two modes: one has a richly layered new-agey sound, and the other is agressively percussive. The same data is fed to the graphics system, which produces blobs that grow upwards from the locations of footsteps. The blobs are superimposed on a live video image showing the legs and feet of people on the carpet (whole bodies of very small people). The video and the forms in it are affected by a virtual wind force, which is increased by stomping or upper-body activity.

At the opening of the piece on 4.28.02 there were 461 visitors (many of them small), who came and played.
 

What it explores
Stomping Ground is a piece about mappings. The same data stream, taken from the natural body motions of museum visitors is used to create two totally different responses—music and graphics, which are blended back into a single experience. It demonstrates that data is only data and how it is digested depends entirely on the form of its presentation. It also explores different levels of user control and influence. Certain actions provoke obvious changes in the system, but others, such as swinging arms, have a subtle effect, which users will only appreciate if they give the piece some time and attention. It is designed to reward exploration.
 

A child becomes engrossed watching reflective blobs that have arisen from his movements.
 

Technical details
The underside of the carpet is lined with a 34X14 grid of piezoelectric wires. These deliver a tiny electric impulse when deformed by foot pressure. These signals are picked up, amplified, and transformed into a MIDI data stream that is fed separately to the music and graphics computers. The radars send out a 2.4GHz wave and determine motion levels by the Doppler shift of the returning wave. This information is folded into the same MIDI stream.
The blobby forms came from some work I had done previously on integrating real and virtual space. (See Installation.)

Simon (left) and Ollie tape the piezoelectric wires to the underside of the carpet.
 

Credits
Project Coordinator: Stephanie Hunt
Hardware Creator: Joe Paradiso
Composer: Kai-yuh Hsiao
Visuals/space designer: Simon Greenwold