DISCLAIMER: This project involved working with mains voltage, and the energies involved could easily be lethal, if not cause serious injury. Please do not try to recreate what you see here.

For this project, I set out to create a device that automatically turns on the shop vac in my dad’s workshop whenever he turns on the power saw. My goals were to build something for cheaper than what is commercially available, with equivalent functionality and footprint.
The build involved a fabricating a custom PCB to facilitate a relay and an ATTINY85 microcontroller, as well as 3D printing an enclosure.
The PCB was created using a dry film lithography and ferric chloride etching process. The holes were drilled and the board was cut out using a benchtop CNC router. The enclosure was printed with eSUN ABS on my custom MK2 clone.
A 5v mains adaptor and a current sensing breakout board were used to facilitate low voltage power for the electronics.