exhibit research Bird's Eye View Installation at Zeum, San Francisco until June 2004

A tilting table allows visitors to navigate across an aerial view of California, zooming down to San Francisco and directly into Zeum. The installation consists of a simple, round table, painted white, witih a conical base. Onto the tabletop is projected high-resolution satellite imagery, with a caped child in the center for orientation. There are no instructions; the design exploits visitors' desire for exploration, and as soon as they touch the table, the method of navigation is revealed. Tilt sensing is accomplished with an Analog Devices ADXL-202EB MEMS accelerometer, which measures tilting angle on the X and Y axes against the force of gravity. It interfaces with a PC through a Parallax Basic Stamp BS2, with a serial connection to the PC. Electronics are on a Parallax prototyping board, which is mounted to the underside of the table, near the center. The table was constructed by Gizmo. After experimenting with various means of tilting, a simple stacking of two hinges was chosen; it works well, preventing the table from spinning round its axis, allowing full maneuverability, while providing hard stopping points and causing the table to tilt back to center when not in use. The PC sits inside the base, and its XGA monitor signal is run to the projector directly over the table. Despite the steep angle of tilt, the projected image does not distort appreciably. There are several software prototypes available; all require the Shockwave plug-in from Macromedia. First Experiment with hardware and software, 14 December 2002 Software Prototype 01, 14 April 2003 Software Prototype 02, 22 April 2003 Kevin Walker