This example walks through the steps required to print a tactile diagram with braille text from a Simulink model.
You can find the starting Simulink diagram here. If you don't have Simulink, you can follow this tutorial with any SVG file (just skip the Simulink steps).
If you start with the default Simulink formatting, it will look something like this:
This font size is too small for clean conversion to braille, so the first step is to increase the font size to 24 and switch to a monospace font like courier new.
Next, we need to export a Scalable Vector Graphics (SVG) file from Simulink. You can do this via the Matlab shell. The diagram must be open in Simulink when you run this command.
>> print('-saddition','-dsvg','addition.svg')
Great! We now have an SVG file!
You'll need to have the vision-impaired-printing directory on your path to run this command. This creates a new .svg file that has the text replaced with braille.
$ svg-braille-converter.sh -i addition.svg
Here's the resulting SVG file:
Simulink SVG with generated braille
Your browser may have trouble rendering this SVG file. Inkscape opens it happily for me.
InkScape is the best tool I have found for doing this. ImageMagick has a SVG to PNG conversion capability, but I have not found it to be reliable.
I like to use 600dpi.
Here's the resulting PNG file:
OpenSCAD is 3d modeling tool. Generate an SCAD file by running:
$ bitmap-to-scad.sh -i addition-braille.png -x 200 -y 200 -s 6
The parameters to this command are:
-iSpecifies the input file-x 200limits the resulting model to 200mm in the x dimension-y 200limits the resulting model to 200mm in the y dimension-s 6slices the bitmap into a six by six grid to eliminate closed polygons
Here's the output (with some lines removed):
Python 3.9.9
Parsing image addition-braille.png
Input image dimensions: (1258, 3900, 3)
Image width 3900 image height 1258
Using split 6
Found 116 contours
Scaling to maximum X span 200mm, maximum Y span 200mm, resolution Nonemm, and height 0.2mm.
Using scale factor 0.0524mm per pixel
Scaling model based on -x (--xmax) constraint of 200mm maximum horizontal size.
Generated SCAD file: addition-braille.scad
bitmap-to-scad reports that the x dimension constraint (200mm) was the limiting factor that it used to scale the model.
Open the resulting .scad file in OpenSCAD, then press the render button.
If you couldn't generate it, you can also find the SCAD file here
Your model will disappear for a little bit, this is normal.
In OpenSCAD, select File -> Export -> STL
Here's the resulting file
Drag the STL file into Ultimaker Cura
Apply the following custom print settings:
| Setting | Value |
|---|---|
| Print Thin Walls | True |
| Build Plate Temperature | 65.0 c |
| Enable Retraction | True |
| Z Hop When Retracted | True |
| Z Hop Height | 1.0 mm |
Click Slice to generate a gcode file. Here is what I generated.
Before you can print, you have to set up the paper on your printer. This is discussed over in Printing Tips.
If your paper stayed flat on the print bed, you should have a pretty nice tactile diagram!
Mine isn't quite perfect (note the thin tendrils of filament left when the extruder lifts up). I'll update this guide as I improve the settings.
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