THOTCON 0xD · United States · 2025

THOTCON 0xD Badge

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.

THOTCON United States Chicago ESP32 ST7789 TFT Capacitive Touch Touch Wheel Buzzer LED LiPo Add-on Badge Contest North America

EventTHOTCON 0xD

SeriesTHOTCON

LocationChicago, Illinois / TOP_SECRET venue

CountryUnited States

People

Authors & Credits

badge design, firmware, production, test, and packaging team

Fourfold

Hackaday.io says Fourfold delivered the THOTCON 0xD badge and handled the PCB, firmware, graphics, puzzles, production/test fixtures, and packaging.

Source

event and contest publisher

THOTCON

The official site and contest page establish the 2025 Chicago event context and badge-hacking contest framing.

Source

nonprofit event producer

THOTCON Infinity NFP

The official home page identifies THOTCON Infinity NFP as the organization producing THOTCON 0xD.

Source

project and repository publisher

Poplicola

The Hackaday.io project and GitHub repository preserve the THOTCON 0xD badge writeup, examples, and source handoff under the Poplicola account.

Source

Why It Mattered

It updates the THOTCON lineage from the 2017 tesserHack maze badge to a modern high-volume attendee badge that paired an official badge contest with a public hardware/software example archive and production-focused maker notes.

Hardware

Hackaday.io documents an ESP32 badge with an ST7789 TFT display, capacitive touch wheel, buzzer, six LEDs, lithium-polymer battery, add-on header, and sub-$20 BOM target. The public repository README corroborates ESP32-compatible hardware, ST7789 240x320 display, six LED pins, three capacitive wheel sensors, center capacitive button, and buzzer pin mapping, while the tree also exposes schematic and board files.

Software & Apps

The public `poplicola/thotcon-examples` repository preserves cleaned-up Arduino/ESP32 demo firmware for the touch-wheel badge: `working` for touch and LED testing, `tonechaser` for musical tone, scale, chord, and arpeggio exploration, and `wheel_visualization` for a menu-driven interactive demo with audio, display, mini-game placeholders, and credits. Hackaday.io says the original badge firmware also included animated menus, audio games, visual effects, timers, hidden screens, and challenge hooks.

Lore

THOTCON's official contest page made the badge contest Gold Badge eligible and told attendees to read the program, solve puzzles, and hack the badge. Hackaday.io frames the badge as a Tamagotchi-style cryptographic scavenger-hunt platform built by Fourfold for 2,000 attendees.

Lifecycle

Add-ons & Upgrades

audio firmware documented

Buzzer and musical tone demos

The public firmware archive includes ToneChaser examples for musical modes while the project writeup documents audio games and badge sound output.

Compatibility: THOTCON 0xD Badge

Source

badge expansion source-backed

Add-on header

Hackaday.io documents an exposed add-on header as part of the badge's expansion and badgelife compatibility surface.

Compatibility: THOTCON 0xD Badge add-ons

Source

firmware examples public demo archive

Arduino/ESP32 demo firmware archive

The `thotcon-examples` repository preserves cleaned-up Arduino/ESP32 examples for touch input, LEDs, audio modes, display output, menus, mini-game placeholders, and credits.

Compatibility: THOTCON 0xD Badge

Source

hardware architecture source-backed

ESP32 touch-wheel badge core

Hackaday.io and the repository README document an ESP32-compatible badge architecture with capacitive touch-wheel input, center button, TFT display, buzzer, LEDs, and LiPo power context.

Compatibility: THOTCON 0xD Badge

Source

input surface source-backed

Capacitive touch wheel and center button

The README documents three capacitive touch sensors for wheel input plus a center capacitive button, matching the touch-wheel interaction model described in the project writeup.

Compatibility: THOTCON 0xD Badge

Source

visual interface source-backed

ST7789 TFT and six-LED display surface

The public sources identify an ST7789 240x320 TFT display and six LEDs as the badge's main visual surfaces.

Compatibility: THOTCON 0xD Badge

Source

Operational history

Issues & Camp Impact

missing rights-cleared image note

No THOTCON 0xD Badge image is published because the current public source trail has not been paired with a reusable original badge or artifact photo or official upstream raster render with source URL, license or permission basis, attribution, and processing notes.

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.

Confidence: local project policy
Status: needs licensed original replacement
Timeframe: current catalogue build
Source note: badge.gallery image policy and THOTCON official 0xD pages, Hackaday.io project, and poplicola/thotcon-examples repository source trail.

public-demo firmware boundary note

The public repository is a cleaned-up demo firmware collection with examples and removed event-specific/proprietary material, while the Hackaday.io project describes a richer original badge firmware with menus, audio games, visual effects, timers, hidden screens, and challenge hooks.

The software description separates the recovered demo archive from the full shipped event firmware so the record does not overstate public source completeness.

Confidence: source-backed but scoped
Status: documented
Timeframe: current THOTCON 0xD pass
Source note: Hackaday.io THOTCON 0xD project and `thotcon-examples` README.

repository-license caveat note

The public `poplicola/thotcon-examples` repository exposes Eagle board files and demo firmware, but GitHub reports no detected repository license and the README only frames the examples as provided as-is.

The catalogue cites the repository as evidence and a user-facing reference without treating its images, firmware, or hardware files as freely reusable beyond what the source itself permits.

Confidence: GitHub API and README recheck
Status: documented
Timeframe: current THOTCON 0xD pass
Source note: GitHub API repository metadata and `thotcon-examples` README.

Resources

THOTCON 0xD Badge project project-owner writeup · Hackaday.io source for Fourfold's 2,000-unit badge build, ESP32, ST7789 TFT, capacitive touch wheel, buzzer, six LEDs, LiPo battery, add-on header, firmware/game/challenge scope, production fixtures, packaging, and sub-$20 BOM target. THOTCON 0xD contests official contest page · Official contest source documenting Gold Badge-eligible contests and the badge contest instruction to read the program, solve the puzzles, and hack the badge. THOTCON 0xD home official event page · Official THOTCON source for Chicago's Hacking Conference, the May 30-31, 2025 0xD dates, TOP_SECRET venue framing, and THOTCON Infinity NFP production context. Touch Wheel Badge demo firmware README firmware documentation · Repository README source for ESP32-compatible hardware, ST7789 240x320 display, six LED pins, capacitive wheel and center-button inputs, buzzer pin, Arduino IDE/TFT_eSPI workflow, and `tonechaser`, `working`, and `wheel_visualization` firmware examples. thotcon-examples repository hardware and firmware examples · Public poplicola repository preserving the THOTCON touch-wheel badge example archive, Eagle schematic and board files, and Arduino/ESP32 demo firmware directories.

Sources

GitHub / poplicola: poplicola/thotcon-examples Retrieved 2026-05-15 · Repository source for public Eagle board/schematic files, C++/Arduino demo firmware directories, and absence of GitHub-detected license metadata in the current pass. GitHub / poplicola: Touch Wheel Badge - Demo Firmware Collection Retrieved 2026-05-15 · README source for the cleaned-up demo-firmware boundary, hardware requirements, pin mapping, Arduino setup, firmware example roles, and Fourfold credit. Hackaday.io / Poplicola: THOTCON 0xD Badge Retrieved 2026-05-15 · Project-owner source for Fourfold's badge design/production role, 2,000-unit quantity, ESP32/ST7789/touch-wheel hardware, firmware feature surface, add-on header, production/test fixtures, and repository handoff. THOTCON: THOTCON Retrieved 2026-05-15 · Official event source for THOTCON 0xD as Chicago's Hacking Conference on May 30-31, 2025, with TOP_SECRET venue framing and nonprofit production context. THOTCON: THOTCON 0xD contests Retrieved 2026-05-15 · Official contest source for the badge contest and Gold Badge eligibility framing.