If you’ve been to a wedding or a downtown coffee shop in the last 10 years, you’ve probably seen those little lightboxes that are so popular these days. They consist of letters placed on a plastic frame in front of a dim white light, and they became twee about five minutes after your hipster friend first got one. However, they can also make a neat basis for an LED display, as [Folkert van Heusden] demonstrates.
The build is straightforward enough, using daisy chains of 32×8 LED matrix modules, two each for the three rows of the lightbox. This provides for a 24 character textual display, or a total display resolution of 64 x 24 pixels. An ESP8266 is used to command the matrixes, which are run by MAX7219 display controllers. Thanks to the microcontroller’s onboard wireless hardware, the display can be addressed in a number of ways, such as using the LedFX DDP protocol or [Folkert’s] Pixel Yeeter python library. Files are on GitHub for the curious.
Quite a few of these exist out in the wild — [Folkert] has built a variety of modded lightboxes over the years with varying internals. The benefit of the lightbox is that it effectively acts as a handy housing for LED matrixes and supporting electronics, while also providing a neat diffuser effect. The lightboxes are also readily wall mountable and generally look more like an intentional piece of signage than most things we might homebrew in the lab.
We’ve featured similar-looking builds before, like this public transit display that was hacked for custom use. If you’re building your own public information boards or other nifty LED displays, don’t hesitate to notify the tipsline!

Awesome!
That approach could work really well with this mini lightbox that you can 3D print.. https://makerworld.com/en/models/1676529-mini-cinematic-lightbox-sign-marquee-display
You’d need to find a small LED matrix to fit in there, but if you can it’d look just as good!
One of the least attractive project photos I’ve seen here. Wires stretched in front of things and that crooked phone, painting project in limbo.
Flat screen TV’s have great diffusing plastic in them, usually free. I’ve never seen one of those letter boxes lit from behind, it looks like a photo slide viewing rack.
Twee?
Stock up on the free diffuser film before TVs go micro-LED or whatever doesn’t need a backlight.
Ever tried to buy that stuff? It’s really really expensive!
Wish I didn’t pass those up at Goodwill or Salvation Army. I’ve been seeing lots of the light boxes often under $5.