Nick Ficara, writing at va3ndf.com, documented how his team replaced the cardstock name tag at Hack the North with a programmable circuit board. Each badge carries an ESP32, a color screen, buttons, an NFC reader, a WS2812B LED and two AA cells. A Lua runtime, a browser-based code editor and an on-device shell let attendees write their own apps.

The design went through four spins at JLCPCB. An EVT with a 10uF capacitor fitted where a 10uH inductor belonged. A screen ribbon the factory said was too dense to solder. An NFC chip that turned out to be a tag, not a reader. A 50 unit PVT were backwards batteries made smoke and two chips arrived rotated, leaving 12 of the first dozen boards dead on arrival.

A reverse-polarity FET went straight into the production run untested on a full board. The final order was 1,750 assembled badges plus 750 blanks, about $20,300, or roughly $11.60 per populated badge against a $5 pitch. Hackers built Among Us over a mesh network, a Pokédex of people and Tux Racer controllers.…