The Responsive Window

During the spring of 2001, we were invited to do an installation of our window tap tracker system at the Ars Electronica Center in Linz, Austria, where it will be running for at least a year. We opened this exhibition at the beginning of September, during the 2001 Ars Electronica Festival. For this installation Che King Leo vastly improved the tracking algorithms and Kaijen Hsiao ported them to a simple DSP platform, the ADMC401 motor controller DSP from Analog Devices. We also packaged the DSP and conditioning electronics into a nice, stable package. Ben Fry of John Maeda's Aesthetics and Computation Group collaborated with us on this project to design the interactive graphics that we used with this installation. What Ben developed was essentially a simple knock-driven drawing program that illustrates the full responsiveness of the system. One knock generates a circle centered at the impact coordinate that oscillates as a function of knock intensity. Two and three knocks extrude a rotating 3D object, with dimensions extending out to the knock coordinates. The rotation rate and fill intensity are similarly a function of the knock intensity. A forth knock sends the object spiraling into the screen (with rate depending on knock intensity), vanishing at the impact location. The color of the object is a function of the spectral content of the sensor waveforms, with knuckle knocks producing bluish objects and metal taps producing reddish objects. Fist bangs flash the entire screen with a bright red transient, with large rotating rings centered at the estimated impact location. Finally, hits above and below the sensor perimeters launch circular waves into the screen, centered on the assumed horizontal location of the hit. This image shows the entire Responsive Window, as seen from the end of the room. Here's another image showing the window in action with Ben's graphics. Here is a short Quicktime video showing the essential system working. Here is a longer Quicktime video showing more interactions with this system. Finally, in a more technical vein, we've posted a link to a FAQ page for troubleshooting the Acoustic Tap Tracker system as installed at Ars Electronica in case of problems (fortunately, it has worked since September 01 without any hint of failure), and will run there throughout 2002.  

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