Sinclair Studios
Publisher of the CHCon 2025 badge challenge walkthrough and technical description.
SourceCHCon 2025 · New Zealand · 2025
CHCon 2025 Badge
ESP32-C3 pukeko badge with OLED, RGB LEDs, Rust VM, and Minecraft server
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.
EventCHCon 2025
SeriesChristchurch Hacker Conference
LocationThe Majestic, Christchurch
CountryNew Zealand
People
Authors & Credits
Jeremy Stott / stoggi
Jeremy Stott published the primary technical writeup for the CHCon 2025 badge; Sinclair Studios also credits him as the badge designer and builder.
SourceWhy It Mattered
It adds New Zealand to the worldwide compendium with a modern Oceania badge that combined wearable art, late-night volunteer assembly, USB interaction, LED feedback, embedded Rust, and an unusually ambitious game-protocol challenge running on a microcontroller.
Hardware
Primary designer notes identify an ESP32-C3 RISC-V microcontroller at 160 MHz with 4 MB flash, 24 WS2812 addressable RGB LEDs, an SSD1306 128x64 I2C OLED, a boot button used for brightness control, and USB Serial JTAG for shell access. The attendee challenge writeup also documents the custom pukeko circuit-board form and USB-C power use.
Software & Apps
Jeremy Stott's technical writeup documents bare-metal Rust (`#![no_std]`) firmware using Embassy async tasks, esp-hal, esp-radio, embassy-net, embedded-graphics, ssd1306, smart-leds, and esp-storage. The badge implemented 15 LED animation modes, a stack-based VM for user LED programs, WebSockets, DHCP/TCP networking, a USB Serial JTAG shell, and a Minecraft 1.21.4 server whose levers controlled the badge LEDs.
Lore
The badge was designed and built by Jeremy Stott, who reportedly assembled badges overnight with family help after a customs delay; the visual design used a pukeko motif whose OLED eyes animate when powered. The challenge path moved from password and VM puzzles into a Minecraft exploration stage that connected the on-badge game world back to the physical LEDs.
Lifecycle
Add-ons & Upgrades
badge app and challenge
source-backed
Minecraft 1.21.4 badge server
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.
Source
badge app and challenge
source-backed
Minecraft server challenge stage
A later challenge stage used badge networking and elevated shell access to start the Minecraft server and solve the in-world lever puzzle.
Source
badge challenge
source-backed
Progressive LED challenge modes
The challenge path unlocked rainbow LEDs, login/password interaction, named LED patterns, and custom pattern definition.
Source
badge programming surface
source-backed
Stack-based pattern VM
Badge users could program custom LED animations with a stack-based bytecode interpreter, persistent flash slots, arithmetic, bitwise operations, and LED opcodes.
Source
display and challenge feedback
source-backed
Dual 12-pixel RGB LED strips
The badge included two addressable RGB LED strips with 12 LEDs each, used for animated eyes and unlocked challenge feedback.
Source
firmware architecture
source-backed
Bare-metal Rust firmware
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.
Source
hardware architecture
source-backed
ESP32-C3 OLED badge core
The CHCon 2025 badge used an ESP32-C3 with mounted OLED screen on a custom pukeko-themed circuit board.
SourceOperational history
Issues & Camp Impact
missing rights-cleared image
note
No local CHCon 2025 badge photo has been added because the recovered article media has not been paired with explicit reuse rights, attribution, and processing notes for catalogue publication.
The entry intentionally keeps an empty hero image rather than copying article photos or publishing generated imagery.
- Confidence
- local project policy
- Status
- needs licensed original replacement
- Timeframe
- current catalogue build
- Source note
- badge.gallery image policy, CHCon event page, Sinclair Studios badge writeup, and Jeremy Stott technical writeup.
source-code archive gap
note
The designer writeup documents source-file names, firmware architecture, and implementation details, but the current source trail did not recover a reliable public firmware repository, schematic, board-file archive, or license statement.
The dossier can now describe the implemented firmware architecture from a primary source while still avoiding unsupported repository, schematic, image, or reuse-rights claims.
- Confidence
- source-backed but incomplete
- Status
- needs public repository or schematic recovery
- Timeframe
- 2025 badge archive pass
- Source note
- Sinclair Studios CHCon 2025 badge challenge writeup and Jeremy Stott technical writeup.
Resources
Building the ChCon Badge 2025
designer technical writeup · Jeremy Stott's post-event technical writeup documenting the ESP32-C3 platform, 24 WS2812 LEDs, SSD1306 OLED, bare-metal Rust/Embassy architecture, stack-based pattern VM, USB Serial JTAG shell, WebSocket implementation, and Minecraft 1.21.4 server.
CHCon 2025 badge challenge writeup
challenge writeup · Sinclair Studios writeup documenting the ESP32-C3/OLED badge, custom PCB, RGB LED strips, USB-C power, challenge stages, Minecraft stage, and build lore.
CHCon 2025 event page
event page · Official event page for the Christchurch Hacker Conference dates, The Majestic venue, and Christchurch, New Zealand location.
Jeremy Stott / stoggi profile
designer profile · Designer profile linked from the badge challenge writeup.
Sources
Christchurch Hacker Conference: CHCon 2025
Retrieved 2026-05-15 · Primary event source for CHCon 2025 dates, venue, and Christchurch location.
Jeremy Stott / stoggi: Building the ChCon Badge 2025: A Minecraft Server on a Microcontroller
Retrieved 2026-05-15 · Primary designer source for ESP32-C3 hardware details, WS2812/OLED/JTAG components, no_std Rust firmware, Embassy async tasks, pattern VM, 15 LED modes, WebSockets, and the Minecraft 1.21.4 server implementation.
Sinclair Studios: CHCon 2025 Badge Challenge
Retrieved 2026-05-15 · Primary technical writeup for the ESP32-C3/OLED badge hardware, RGB LED strips, USB-C power, challenge interaction, Minecraft stage, and Jeremy Stott designer credit.