I recently took part in a study on the feasibility of 3D printing circuits using electrically conductive filament. We were given a PCB which basically was just a breakout for a Seeeduino ESP32-S3 that broke out the IO, Ground, and 3v3 lines to much larger pitch holes (2.5mm). This meant that we could insert a pause part way through the print, slot the board onto columns designed to fit the holes, and print over them - sealing the connection.

We had to print a ladybird that acts as a media controller as part of the introduction

We had to pick something to design and print ourselves, and I had an idea. I’ve wanted a Stylophone for a while, but never got round to buying one not the least because I’m actually not very musical and knew it would just sit there and not get used. So I figured this was a perfect opportunity.

If you don’t know what a Stylophone is, it’s a miniature analog synthesiser played with a stylus.

How very Retro.

Now my idea was relatively simple, I could print the keys out of conductive filament, run them to IO inputs on the board, and run 3v3 through a stylus also printed with conductive filament. I could continuously read the inputs as analog values, and when a key was pressed I’d see the reading go high.

The catch, of course being that the ESP32-S3 only has nine inputs, and there are 20 keys on the Stylophone. ಠ_ಠ

Bla bla different length traces different resistance

Learned onshape

insert onshape pics

insert print pics

insert final pics

talk about problems - cross-talk, no pull-low resistors

talk about potential V2