I’m getting melancholic – so much has happened since then! (But the design with the two transistors (and nothing more) was actually quite nice, it generated a stable rectangular signal … 🙂 )
I have updated the instructions for building the free Arduino version. Enjoy! (But be careful … High Voltage!)
OK, the transformer is not yet fully mounted and there are still some design issues with the 3D printed plastic parts. But all in all, it’s done.
Also note the 3D-printed compartment for the red filter capacitor (just behind the display). This has to be secured because it’s the really dangerous part (high voltage!).
Yes, I finally managed to upload the Arduino version. And the very comprehensive documentation, of course … If you come across any errors, please do not hesitate to contact me! 🙂