Series
Chicago hacker-conference badge lineage, represented by the source-backed 2017 0x8 ATmega32u4 tesserHack maze badge, 2019 0xA / Infinity ESP32 badge from DePaul IRL and Poplicola's public workshop archive, 2021 0xB ESP32 retro-controller badge by the Fourfold/Rehrig team, the 2023 0xC laser-tag badge with custom enclosure work, and the 2025 0xD ESP32 touch-wheel badge with TFT, audio, LEDs, games, and public demo firmware.
Chicago hacker-conference badge lineage, represented by the source-backed 2017 0x8 ATmega32u4 tesserHack maze badge, 2019 0xA / Infinity ESP32 badge from DePaul IRL and Poplicola's public workshop archive, 2021 0xB ESP32 retro-controller badge by the Fourfold/Rehrig team, the 2023 0xC laser-tag badge with custom enclosure work, and the 2025 0xD ESP32 touch-wheel badge with TFT, audio, LEDs, games, and public demo firmware.
Badges
ATmega32u4 tesserHack maze badge
The THOTCON 0x8 badge was a Chicago electronic conference badge built around an ATmega32u4, four RGB NeoPixel LEDs, three potentiometers, micro USB, two CR2032 coin-cell holders, and tesserHack stock firmware for an 8x8x8 maze game.
DePaul IRL ESP32 badge with capacitive pads, LEDs, speaker, and microphone
The THOTCON 0xA / Infinity badge was a Chicago electronic conference badge produced with DePaul's Idea Realization Lab for the May 3-4, 2019 event. DePaul Newsline reported a six-month, 1,700-unit custom circuit-board badge build; the public Poplicola repository documents a SparkFun ESP32 Thing Dev base, five capacitive touch pads, six LEDs, speaker output, microphone input, stock-firmware restore commands, and Arduino examples.
ESP32 retro-controller badge with LEDs, buzzer, accelerometer, and Wi-Fi
The THOTCON 0xB badge was a rescheduled-2021 Chicago electronic conference badge in a retro controller / circus-ticket form factor. Rob Rehrig's first-hand writeup documents an ESP32 main controller, reverse-mount RGB and single-color LEDs driven by an IS32FL3731 LED driver, capacitive touch buttons, piezo buzzer, accelerometer, 2.4 GHz Wi-Fi node behavior, IRC remote connectivity, and serial interface.
Contra-themed laser-tag badge with custom clear-PC housing
The THOTCON 0xC badge was a Chicago electronic conference badge built around a Contra-inspired, conference-wide laser-tag game and a custom injection-molded clear polycarbonate housing. Rob Rehrig's first-hand writeup documents the badge theme, enclosure work, IR receiver/emitter layout, TIR lens work, Xometry manufacturing path, and roughly 2,000-badge production scale.
ESP32 touch-wheel badge with TFT, audio, LEDs, and games
The THOTCON 0xD badge was a Fourfold-built electronic conference badge for the May 30-31, 2025 Chicago event, documented as a 2,000-unit ESP32 touch-wheel badge with ST7789 TFT display, buzzer, six LEDs, LiPo power, add-on header, games, visual effects, and challenge hooks.