Fiber Optic Matrix Display
Introduction: Fiber Optic Matrix Display
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.
Supplies
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. 769
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
Step 1: Design Files
This design is made up of mostly flat parts in a big sandwich. Because of this, there are no strict thickness requirements, in fact in the whole design the only critical dimension is the spacing of the LEDs in the array because we can't change them. Everything else is up to you and should be apparent when we look at what each part does.
3D models: A STEP file is attached. Instructables doesn't support ZIP or IGES files, so the original solidworks model and can be found here: https://github.com/elliotmade/Fiber-Optic-Matrix-Display/tree/main/3D%20Model
DXF flat files: There is a file for each of the flat parts -
* Back plate - this is just for structure, it makes room for some electronics to be tucked in, but it could be omitted. M3 tapped holes in this part.
* Middle plate - this supports the back of the LED matrix
* Gasket - this keeps the light from one LED separate from it's neighbors
* Front plate - this holds each fiber up to each LED
* Main display grid - this is the smaller grid that brings all of the fibers together and forms the face of the display
Other stuff:
* Two posts that hold the display grid to the front plate. They are drilled and tapped for an M3 screw at both ends
* Eight spacers that go between the back and middle plates
* M3 screws. There are 8 holding the sandwich together, and four holding the posts on. Choose lengths or diameters that suit you. Use a nut on the back plate instead of the tapped holes if you prefer.
Step 2: Make the Flat Parts
I made each of these parts out of a different material, just for fun.
* Front plate: This is a black plastic, maybe polyethylene, that I found in my pile. 215