The idea that kicked this off was straightforward: wiez5 wanted Ambilight-style lighting behind the TV. Once it was up and running, the results came out better than expected, which is a nice place to land.
The build splits the work neatly. A Raspberry Pi captures the video signal through a UT007-based frame grabber and pushes LED states to an Arduino Nano over USB serial. To get a copy of the picture, a 4K HDMI splitter sends one output to the TV and the other through an HDMI-to-AV converter into the grabber. Hyperion on OpenElec runs the show, and the 266 WS2812B LEDs have their own dedicated 5V 10A supply.
The effect is the payoff: the strip behind the 65-inch panel throws colored light onto the wall that tracks the screen content in real time. One viewer compared it to surround sound, saying it is not distracting and feels empty to be without, and that comparison feels apt.
There is still work to do. The color balance needs more tuning: browns, yellows and whites come out poorly and the LEDs run somewhat too bright, though Hyperion allows adjusting colors and intensity toward better settings. The supply is another constraint, since 10 amps cannot handle every LED at full white and the intensity had to be lowered. Anyone copying this should also know the Adalight sketch has trouble supporting more than 256 LEDs, which could stump people.
Project by wiez5. Watch it on their YouTube channel: