Monday, April 03, 2006

An Interactive LED Dining Table

An Interactive LED Dining Table
Type: Maker Table Top Exhibits

We made a dining table with a frosted glass top lit by 448 multicolored LEDs that respond, in a complex and gentle fashion, to input generated by motion above the table while we eat.The LEDs are controlled by a 16-node 1-D analog computer network. Each node has an amplified photodiode that senses changes in ambient light above its region of the table. An analog integrator (memory) averages that signal along with input from its neighbors, and the resulting signal is used to drive one of two strands of 14 LEDs (depending on polarity) with intensity that depends on the integrated value. Each node consists of one photodiode, one quad op-amp IC, nine resistors, and four capacitors that we hand-soldered onto a tiny piece of plain perfboard. We mounted the nodes to sheets of masonite pegboard, such that the output LEDs fit through the holes. After (a dozen or so evenings of) soldering, the pegboard with its electronics and a power supply was set into a stained-wood table frame that we made out of birch and poplar, and topped with glass recycled from a desk top.We'll bring the table itself and have it running at (as) our table. We'll also bring a miniature version of the table electronics-- a four-node network-- for demonstration, the circuit diagram, and a couple pictures of the build process.
Related site:
Windell H. Oskay,Lenore M. Edman,Christian W. Brookfield