Yesterday I built the first touch pad, here's how it went:
First of all, I bought a 600mm x 300mm sheet of 1mm clear acrylic, which is more than enough to fit all 7 pads. I learned that 1mm acrylic sheet is almost double as expensive as 3mm sheet. It is also significantly more difficult to find. For both these reasons, I might consider alternative materials in the future.
Here is the DXF file for the acrylic pads: https://github.com/luiszayas/kazumi/tree/master/hardware/pads
I'm not sure if Github is the best place to document a project with both hardware and software. Any thoughts? In any case, I will make sure I upload every file and document the repository so anyone can replicate or modify the project.
After cutting the acrylic, I went on to cut the electrodes using a Roland GX-24. I checked this website: HOW TO GET WHAT YOU WANT. This is a great resource for e-textiles and I followed their advise on vinyl cutter settings, although I went a little higher on Pen Force as I have had problems in the past with blades that aren't as sharp as the first day. Settings were Pen Force:100gf and Speed: 1cm/s.
Here is the DXF file for the electrodes: https://github.com/luiszayas/kazumi/tree/master/hardware/electrodes
And to finish, here are a couple of pictures (front and back) of the finished touch pad:
I'm very happy with how they've turned out (they just need some sort of protective film so the foil doesn't peel from constant friction) and really looking forward to putting all of this together.