THOTCON
The October 8-9, 2021 rescheduled Chicago THOTCON edition whose official archive, workshop listing, Fourfold portfolio, and Rob Rehrig project writeup preserve the 0xB electronic badge.
Chicago, Illinois · United States · 2021
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.
Lifecycle
The badge added a piezo buzzer for simple tones, including circus-themed and button-feedback jingles.
Returning badge features included capacitive touch buttons, 2.4 GHz connectivity mostly as a Wi-Fi node, remote connectivity via IRC, and a serial interface.
Rob Rehrig describes the 0xB badge as an ESP32-based design in an NES-controller and circus-ticket form factor.
An accelerometer was added and paired with the buzzer to create a tone-generator/synthesizer controlled by badge tilt.
A late GPIO0 buffer design caused battery-powered badges to enter Download boot mode until the team fixed DTR with an R19 pull-up resistor before conference shipment.
The badge used reverse-mount RGB LEDs behind the THOTCON letters, single-color reverse-mount LEDs near capacitive buttons, and an IS32FL3731 driver for animation without heavy CPU load.
Operational history
The record preserves a real manufacturing and bring-up issue as part of the badge history rather than presenting the 0xB build as frictionless.
The United States record remains source-backed and image-free rather than copying source-page media, documentation screenshots, event photos, social media, placeholders, or generated approximations.
The catalogue records verified hardware behavior and production context without claiming that the complete design archive is public.