Add-on dossier
A linkable lifecycle record for hardware expansions, app ecosystems, firmware upgrades, cases, radio parts, and post-event badge experiments.
The official event page describes a front-lit e-paper display and twelve-button keypad; the public hardware repository associates the keypad with a TCA9535 I²C expander.
Badge context
The cluster's own 39C3 page ties the CDC Badge repository to the completed December 27-30, 2025 Hamburg assembly context.
The firmware README documents ESP-IDF/PlatformIO, FIDO2/WebAuthn, GPG/SSH, TOTP, password-vault, plugin, BLE, and data-loss/early-beta caveats.
RIAT's public CDC Badge source tree with KiCad hardware, printable cases, documentation, fabrication instructions, expansion descriptions, and linked firmware projects.
Public CERN Open Hardware Licence v2 Permissive source for the RIAT CDC Badge project, with third-party component attribution retained separately by the repository.
Primary official Congress event page explicitly calling the artifact an electronic conference badge and devboard, and naming its TROPIC01, ESP32-S3, e-paper, LiPo, keypad, and expansion surface.
Official 39C3 assembly page for the Critical Decentralization Cluster, which lists the CDC Badge presentation in its recorded assembly programme.
Public GPL-3.0 firmware project for CDC Badge v1.0/v1.1 hardware. Its January-July 2026 public history is kept separate from an asserted 39C3 deployed image.
Source-published checklist covering BQ25895 charge-current/power settings, USB interaction, and TROPIC01 sleep requirements; it is not proof of configuration on every event unit.
Public v1.1 release evidence for the CDC Badge hardware tree. It does not identify which source revision, if any, was on a particular 39C3 physical unit.
Source trail
Official assembly source that places the CDC Badge presentation in 39C3's cluster programme and describes the Critical Decentralization Cluster's event role.
Primary official Congress source identifying the CDC Badge as an electronic conference badge and devboard with TROPIC01, ESP32-S3, e-paper/frontlight, LiPo battery path, keypad, and expansion ports.
Cluster-owned retrospective for the completed 39C3 assembly, its dates and location, and its direct CDC Badge repository link.
Primary CERN-OHL-P-2.0 license source for the CDC Badge hardware project; it does not automatically license every unrelated event mark or media asset.
Versioned public v1.1 CDC Badge release. It is source-release evidence, not a confirmed physical 39C3-unit firmware or bill-of-materials mapping.
Primary configuration-caution source for BQ25895 charging/power settings, USB interaction, full power-off, and TROPIC01 sleep handling.
Primary open-hardware source for the ESP32-S3/TROPIC01 board, e-paper/keypad/expansion design, KiCad fabrication material, linked firmware, and project-level licensing.
Primary public firmware-status source for the documented secure-element application surface and explicit early-beta/data-loss/security-critical-use warnings.
Public post-event GPL-3.0 firmware source for CDC Badge v1.0/v1.1 hardware. Its later source availability is not treated as a 39C3 deployment ledger.