I built something similar that I called LowBoard. It was a 12x16 array of addressable color LEDs that was originally for low-rez halloween pictures (so good timing!) and we displayed it in the window as part of our display. Then I built a web app and hooked it up to the internet to let anyone draw and display an image for 20 seconds, kind of a physical snapchat. Then an hour or so later and ~100 12x16 dick-picks I disassembled it. Several lessons learned!