This is a design tweak of our other one line braille slate.
( https://www.thingiverse.com/thing:1353118 ) This new one can be printed without too much trouble on an FDM printer. (The other one works better with SLA printing.) Either print with a small nozzle, or in your slicer "force" your .4 nozzle to print at .3. Use only one shell and 100% infill. You also might have to print slower than normal. You can't size this up as Braille dots are a set scale/distance apart.
For a stylus I like to use a dental tool - the one with a blunt tip (not the super sharp one). You can also use toothpicks though the tips start to dull after a bunch of punching so you might use several :-) Yes, it does poke through the paper, but if you smooth it lightly on the other side after you're done, it is quite readable for a blind person.
Remember you are writing backwards so a blind person can read it forwards :-) So start punching on the right and work left, use our guide to make sure you're also punching the letters in backwards.
Here's a video using it - sorry I'm so slow! It's sped up after the first line:
Extrusion Width: Manual: 0.30mm