“Behold! This is a 35x7 RGB matrix display powered by a Raspberry Pi Pico and a bunch of WS2812B LEDs (Neopixels). I’ve never see anything quite like it on the internet before, hopefully I’m the first!
The display is a bit absurd, as it takes a much larger grid of LEDs (64 square inches) and condenses them down to a much smaller size (1.5 square inches).
In this instructable I will discuss how I constructed this and provide you with everything you need to make one of your own, but I encourage you to take this concept and come up with your own design.
They key ingredients that make this work are:
16x16 WS2812B matrix. Adafruit sells this one: https://www.adafruit.com/product/2547, and there are many other cheaper ones from the usual places online, like so: https://www.amazon.com/WESIRI-WS2812B-Flexible-Individually-Addressable/dp/B07PB2P81N
Raspberry Pi Pico. https://www.digikey.com/en/products/detail/raspberry-pi/SC0915/13624793. Just about any other common microcontroller can do this as well, but you’ll be on your own to program it unless it can also use circuitpython.
PMMA fiber. There are two common types - “side glow” is meant to emit lite throughout the length of the fiber, but for this application we want “end glow” which minimizes the losses out the sides and sends most of the light down the length of it. I used 1.5mm, but there are many other sizes. https://www.amazon.com/dp/B07W6ZRJB6
The rest of the materials are up to you - choose whatever is best in your case for availability/cost/ease of manufacture. Many of the parts could be 3d printed, cut on a CNC mill or router, laser cut, or even made the old fashioned way with hand tools.
The one critical part that might dictate what material you use is the main display face where the fibers are condensed together; in this part there are a large number of small holes that are very close together:
If you’re drilling, the material should be sturdy enough not to deform adjacent holes
FDM printing may give undersized or non-round holes
Laser cutting may be a good fit, but be aware of the taper for your focal length
Resin printing is a good bet, but you still need to dial in the final hole size - drilling the resin after will probably shatter or break into adjacent holes”