Christchurch Hacker Conference
The Christchurch Hacker Conference edition held October 29-31, 2025, whose attendee badge paired an ESP32-C3, 24 WS2812 RGB LEDs, SSD1306 OLED, USB Serial JTAG shell, bare-metal Rust firmware, and progressive badge challenges.
The Majestic, Christchurch · New Zealand · 2025
CHCon 2025's attendee badge was a custom circuit-board badge with an ESP32-C3, SSD1306 128x64 OLED, 24 WS2812 RGB LEDs, USB Serial JTAG shell access, bare-metal Rust firmware, a stack-based pattern VM, and a Minecraft 1.21.4 challenge server.
Lifecycle
The badge implemented a Minecraft Java Edition 1.21.4 server on the ESP32-C3, with in-world levers mapped back to the 24 physical RGB LEDs.
A later challenge stage used badge networking and elevated shell access to start the Minecraft server and solve the in-world lever puzzle.
The challenge path unlocked rainbow LEDs, login/password interaction, named LED patterns, and custom pattern definition.
Badge users could program custom LED animations with a stack-based bytecode interpreter, persistent flash slots, arithmetic, bitwise operations, and LED opcodes.
The badge included two addressable RGB LED strips with 12 LEDs each, used for animated eyes and unlocked challenge feedback.
The designer writeup documents no_std Rust firmware on ESP32-C3 using Embassy async tasks, esp-hal, esp-radio, embassy-net, embedded-graphics, ssd1306, smart-leds, and esp-storage.
The CHCon 2025 badge used an ESP32-C3 with mounted OLED screen on a custom pukeko-themed circuit board.
Operational history
The entry intentionally keeps an empty hero image rather than copying article photos or publishing generated imagery.
The dossier can now describe the implemented firmware architecture from a primary source while still avoiding unsupported repository, schematic, image, or reuse-rights claims.