Next to unique clocks, it seems that coffee tables are some of the best platforms for hackers to display their unique skills in a practical setting. This particular table by Creativity Hero’s Marija takes the form of a grid of sensors and programmable LEDs separated by MDF baffles. When someone places a drink or hand above any of the pixels, it lights up in a different color.
The video shown below outlines the build process, which involves a large amount of woodworking to get the baffles cut out of MDF, and the bottom cut out of pine, for a table that would look at home in a respectable techie living room. The top is made of a translucent pane of glass in order to diffuse the light and hide the electronics underneath. Holes are cut in the bottom piece of MDF to arrange each of the IR emitter/sensor modules, modified to correctly sense objects placed high above them.
Each of the sensor pairs is wired into an Arduino Mega board, which uses its expansive I/O capabilities to take inputs from each of the 45 sensors needed to control this IR array. It then sends signals out to the LED modules (obtained by cutting up and soldering a strip) via a single output. A Bluetooth-based smartphone app allows for control of the pixel colors.