Hacker and mood ring detractor Evan McMahon, like many of us, is generally disappointed in the performance of mood rings. Unlike literally everyone else, however, he decided to do something about it, and created a wall that reacts to his mood — or at least his facial expression.
As explained in his project video, McMahon’s setup uses an iPhone camera, along with Unity running on a nearby computer to decide whether he’s smiling (happy) or frowning (sad). Based on this information, lighting data is then passed on to an Arduino Uno corresponding this perceived mood. When he’s happy, the light wall shines a bright white color, then goes into dance mode with lights blinking joyfully. When he frowns the lights turn to a mostly blue color, with white light accents to indicate rain and occasional lightning. Notably, the system doesn’t seem to be thrown off by McMahon’s facial hair, though one would have to assume there is some limit to how much it can handle!
The light wall itself is constructed with what McMahon describes as “80 gazillion” programmable LEDs. These are separated by a panel made out of poster board, and diffused with squarish disposable cups. While code for the build isn’t listed, the video is certainly entertaining, and it’s a concept that wouldn’t be too hard to duplicate with a little electronics know-how and/or Googling.