This is a customisable diffuser grid for an LED matrix display, for displaying animated patterns or pixel art.

LED matrices can come in a number of sizes, either prebuilt units (8x8 or 16x16 are common sizes), or for larger displays, you can solder together strips of LEDs to build a grid, row by row.

Plenty of how-tos on making matrices that I've seen have the diffuser laser cut out of cardboard or other material. I'm a long way from a laser cutter, hence this design.

The aim of this design is to allow you to print a grid of arbitrary dimensions, irrespective of your printer's print area, by printing it as a series of units that snap together.

Video of assembly

To do this, you will need to make multiple uses of the customiser to print units with and without edges to generate a full grid. You can also include optional attachment points on the edges and base of your design, to hold your matrix securely in a frame.

A quicker way to generate a set of printable files is to download the included .scad source file for the design, and open it in the free Openscad and generate your stl files in there, directly.

This was my first Openscad model, it is a reproduction of my original single-use Sketchup design. Openscad is a powerful tool for generating complex print-ready geometry, from code, and I'm happy to have added it to my modelling toolbox.

Prints are generated upside down, so if your first layer suffers from a bit of "elephant's foot", this is not the end of the world. If your are planning to paste a paper diffuser to your grid, it can be an advantage!

UPDATED 28/12/21 - Dogfooded the design some more in printing a full 32 / 32 grid (16 prints, 9 models) from it, improved mounting points size and positions.

If you are comfortable using node.js on the commandline, here is sketch of a script that will allow you to generate a full set of STL files (up to 9 files) for a grid of a given size, with a print bed of a given size:

https://gist.github.com/hughc/60bd251dc47857ff49163c6530db5506