The trickiest part of a matrix this size has to be keeping thousands of hanging pixels straight and evenly spaced across a 16-foot door. bobko69 tackled it with 3D-printed black spacers at the bottom of each string, plus 5/16 inch carriage bolts acting as weights, and the result is the clean, even spacing that was clearly the goal from the start.
The construction is tidy. Fourteen custom blue PCBs, labeled version 1.0 with 5cm spacing, cover the door. Each board handles three loops of 64 seed pixels, running 32 pixels down and 32 back up, and pairs of boards are joined with wire loops. Two boards together give 384 pixels per port, and seven ports on the controller drive the whole thing, for 2688 pixels in a 32 by 84 grid.
Several choices stand out to me. Seed pixels keep the weight down, which matters on something hanging in front of a moving door. Even better, the design leaves the door fully functional, so a car can still go in and out without any teardown. Gerber files and the spacer STL are shared in a GitHub repository, so anyone can replicate it, though printing the spacers means owning a 3D printer or using an online service.
One open item: hot glue sits over the solder pads and wire as strain relief, and the maker suspects a glob of silicone might hold up better. There is also a plan for handling strain relief differently in version 2. The content itself looks fun, from scrolling red and white MERRY CHRISTMAS text to a walking Santa, falling snowflakes, simulated fireworks, and swirling pink, green, and blue patterns.
Project by bobko69. Watch it on their YouTube channel: