How to Make a Diffusor for Your LED Matrix

Hi, in this Instructable I want to show you how to create your own diffusor for a LED Matrix. To do this we will use a 3D printer and OpenSCAD. In this tutorial I will use a LOL-Shield by Jimmie ( http://jimmieprodgers.com/kits/lolshield/ ) also I will explain, how to design a diffusor for different matrix sizes and shapes.

As I recently was at the 31C3 in Hamburg i got a LOL-Shield from Jimmie. This shield is holding 126 LED´s which are Charlieplexed. After coding some animations and a game on it I thought that the LED´s where too bright. Because I wanted to keep the greyscale ( dimming ) of the matrix I decided to design and build a diffusor.

Demonstration:

Step 1: Requirements

Material:

A LED Matrix

Black Filament

White Filament ( or in the color your LED Matrix is )

Tools:

A 3D Printer ( Single Extruder )

A working bench

Computer

caliper

Additional: A mallet or a rubber mallet

Software:

OpenSCAD

Step 2: Measure the Matrix

Our first step is to measure the matrix.

What we need:

Total lengh ( with planned border )

Total width ( with planned border )

Total height ( optional LED height + 3 - 4 mm )

Led size ( normally 3 or 5 mm sometimes 8 or 1 mm )

Spacing between Led`s

Optional you can measure the PCB to add holders / screws / a housing

I didnt do it, I only added spacers ( you will see later )

So the measurements of my board where:

Lengh: 70mm ( boarder 1 mm each )

Width: 42 ( boarder 1 mm each )

Height: 6.5 mm

Led size: 3 mm

Spacing: x = 1.6 y = 2 (i got not a square matrix)

Step 3: Generate Frame

Now we have to generate the frame in OpenSCAD. I wrote a simple code for that, you can fill in your measurements in the top and then press F5 to preview your frame. If you are good with it you can press F6 to render it and then File >> Export >> As STL to create a printable file.

Code:

lengh = 70;

width = 42;

height = 6.5;
numberx = 9;

numbery = 14;

boarders = 1;

led_size = 3;

spacingx = 1.6;

spacingy = 2;

rotate([180,0,0])

difference(){

union(){

cube([width,lengh,height]);

}

union(){

for(i = [0:numberx -1]){

for(j = [0:numbery -1]){

translate([(i*(led_size+spacingx))+boarders,(j*(led_size+spacingy))+boarders,-1]) cube([led_size*1.025,led_size*1.025,10]);

} } } }

Step 4: Generate Diffusor

Now we need to generate the diffusor. The diffusor is ( are ) tiny white squares which you put into the frame, to generate them we also have a OpenSCAD code. Fill the Led size in the following code.

Change the height to get the darkening effect you desire, 2 worked best for me.

led_size = 3;

height = 2;

numberx = 9;

numbery = 14;

for( i = [0:numberx-1]){

for(j = [0:numbery-1]){

translate([i*3.5,j*3.5,0])

cube([led_size*1.0125,led_size*1.0125,height]);

} }