Security Fest 2018 Challenge Badge
USB HID and serial puzzle badge
A simple Security Fest 2018 challenge badge with USB-A, two buttons, four DIP switches, red/green LEDs, HID text output, serial puzzle flow, and an open SecBadge hardware repository.
Country dossier
Sweden
Worldwide badge coverage for Sweden, grouped into seeded badges, event editions, add-ons, operational issues, resources, and evidence sources.
Seeded artifacts
Badges
Security Fest 2022 Tram Badge
Blinky Gothenburg tram badge
A conservative first-pass record for Security Fest's 2022 tram-inspired badge, remembered in later badge writeups as a fun blinky object inspired by Gothenburg trams with a Rickroll reference.
Security Fest 2023 Gothenburg Skyline Badge
UV-printed cyberpunk skyline CTF badge
A full-colour UV-printed Security Fest badge inspired by Gothenburg's skyline with a cyberpunk treatment, backside-mounted components, Micro-USB CTF interface, cryptography puzzles, and soldering-village LED personalization.
Security Fest 2024 Feskekôrka Piano Badge
Music-and-airship CTF building badge
A Security Fest 2024 badge shaped around Gothenburg's Feskekôrka fish-market landmark, with piano/touch-key gameplay, an airship story CTF, LEDs, USB-C serial interaction, and documented attendee/speaker/crew variants.
Flutter & Friends 2025 E-Paper Conference Badge
NFC-updatable passive four-color e-paper developer-conference badge
Flutter & Friends' organizer-published conference-app source added a Friends Badge editor on August 30, 2025: users could select an image, preview it with dithering, and write it to the conference badge through NFC. The companion `friends_badge` package explicitly describes control of the Flutter & Friends e-paper conference badge, and its implemented target profile is a passive four-color e-paper device. The source-backed record establishes a real event-linked electronic artifact at the completed Stockholm conference, but does not establish that every attendee received one, that it served as admission, or what final physical units contained.
Security Fest 2026 RP2040 Badge
Source-backed RP2040 LED-matrix conference badge
Security Fest 2026's public firmware repository identifies this as the official conference badge: a small, hackable RP2040 device with a 9×9 LED matrix, six buttons, USB surface, and public firmware. The official event site confirms the completed May 28-29 Gothenburg conference, while a contemporaneous attendee report credits Carl Vargklint's badge work. Allocation and delivery are not documented.
Events
Camp and Event Editions
Security Fest 2018
The Swedish Security Fest edition with a simple but public challenge badge built around USB HID, serial output, DIP-switch paths, and an open SecBadge hardware repository.
Security Fest 2022
The Swedish Security Fest edition with a publicly remembered tram-inspired badge that blinked lights and included a Rickroll reference.
Security Fest 2023
The Swedish Security Fest edition with a UV-printed Gothenburg Skyline CTF badge, soldering-village LED personalization, and serial cryptography challenges.
Security Fest 2024
The Swedish Security Fest edition with the Feskekôrka Piano Badge, a music-and-airship CTF badge documented through Hackster and Hackerware build notes.
Flutter & Friends 2025
The August 31-September 2, 2025 Stockholm Flutter and Dart developer conference at Kulturhuset Stadsteatern. Its organizer-published conference-app source encodes the event schedule and, on August 30, added a Friends Badge extra that lets users select and dither an image before writing it to an e-ink conference badge through NFC. The source confirms an event-linked electronic artifact and mobile workflow, but not ticket eligibility, attendee-wide allocation, credential use, final physical configuration, or media rights.
Security Fest 2026
The completed May 28-29, 2026 Security Fest edition in Gothenburg. Its public firmware repository calls the associated artifact an official, small hackable conference badge and documents an RP2040, LED matrix, buttons, USB surface, and public source tree; allocation, final production revision, and image rights remain unproven.
Lifecycle
Add-ons & Upgrades
Security Fest 2024 Feskekôrka Piano Badge
documented solder option
Mini speaker piano mode
Hackerware documents sticking a mini speaker on the backside and soldering its leads at LS1 to play the piano.
Security Fest 2022 Tram Badge
historical
Rickroll lore
The same retrospective source preserves the badge's Rickroll reference as part of its social memory.
Flutter & Friends 2025 E-Paper Conference Badge
source-backed
NFC e-paper image-transfer path
The companion package documents image transfer to the badge through NFC using a Type 4/NfcA tag workflow. This identifies the update surface without exposing a claim about any active radio or every event unit.
Security Fest 2022 Tram Badge
historical
Blinky tram motif
The later writeup remembers the 2022 badge as a fun blinky badge inspired by Gothenburg trams.
Security Fest 2018 Challenge Badge
historical
DIP-switch clue paths
The writeup documents multiple clue texts triggered by toggling DIP switches and pressing a badge button, turning a small hardware input surface into the puzzle selector.
Security Fest 2024 Feskekôrka Piano Badge
historical
Airship storyline CTF
The badge CTF is framed as an airship journey with touch-key and serial navigation, games, riddles, and harder crypto, reverse-engineering, and memory-corruption challenges.
Security Fest 2023 Gothenburg Skyline Badge
historical
Cryptography serial CTF
The badge CTF uses a serial monitor at 9600 baud; sending three stars enters CTF mode and solving eight cryptography puzzles unlocks eight building lights.
Security Fest 2018 Challenge Badge
historical
HID and serial puzzle flow
The badge presents itself as both HID and serial; HID button output gives onboarding and clues, while listening on the serial interface reveals the path into the PGP/key-recovery challenge.
Security Fest 2026 RP2040 Badge
documented
9×9 LED-matrix interface
The public README documents a 9×9 IS31FL3731 charlieplexed LED matrix and four front LEDs as the badge's visible interaction surface.
Security Fest 2026 RP2040 Badge
public source
Public welcome, animation, and game firmware
The repository's public Arduino/C++ source describes display states, animations, games, and personalization for the badge without establishing a final production firmware image for every unit.
Security Fest 2024 Feskekôrka Piano Badge
documented solder option
Airship LED unlock path
Hackerware documents replacing C1 and C2 with 22 pF capacitors, then adding SMD LEDs and resistors at D9-D13 and R8-R12 to play the CTF and unlock airship lights.
Security Fest 2023 Gothenburg Skyline Badge
historical
Soldering-village LED personalization
Security Fest hosted a soldering village so attendees could solder their own LEDs in chosen colours and personalize the badge.
Flutter & Friends 2025 E-Paper Conference Badge
source-backed
Dithered raw-bitmap conversion
The package crops, resizes, and dithers an image before sending raw, uncompressed, column-major bitmap data to the documented badge target.
Flutter & Friends 2025 E-Paper Conference Badge
source-backed
Passive 240×416 four-color e-paper profile
The package's implemented BadgeSpecification profile is a passive 240×416, 3.7-inch black/white/yellow/red target. It is the documented software target, not a full bill of materials or physical-production record.
Security Fest 2026 RP2040 Badge
documented
USB and expansion surfaces
The README documents USB CDC, controller/HID-capable USB behavior, an SAO port, and marked GPIO. It does not identify a supported add-on ecosystem, compatibility list, or final per-unit wiring revision.
Flutter & Friends 2025 E-Paper Conference Badge
source-backed
Cross-platform NFC capability integration
The dated conference-app commit adds Android NFC declarations and iOS NFC reader configuration alongside the Friends Badge feature. This is source evidence for app integration, not a guarantee of device compatibility or successful writes for every participant.
Flutter & Friends 2025 E-Paper Conference Badge
organizer-published source
Friends Badge conference-app editor
The organizer-published app exposes a Friends Badge extra where a user can select an image, preview it, and invoke the badge write action. The source records a public customization interface, not a particular attendee's installed build or completed update.
Operational history
Issues & Camp Impact
The package documentation contains generic active-badge and Bluetooth Low Energy protocol material, while its sole implemented BadgeSpecification target is passive and the organizer app's documented write action is NFC based. No reviewed source ties a battery-powered or Bluetooth-capable variant to the 2025 Flutter & Friends hardware.
The record does not claim Bluetooth, BLE, a battery, or active-radio behavior for the actual conference badge merely because the reusable package documents additional protocol families.
The organizer-published app calls the target a conference badge and adds a user-facing write workflow immediately before the event, but reviewed sources do not state who received a badge, whether every ticket holder was eligible, whether it was optional, whether it functioned for entry, how it was handed out, or how many units existed.
The catalogue records a factual event-linked electronic badge and companion workflow without upgrading it to an all-attendee entitlement, admission credential, or distribution ledger.
Public app and package code establishes a companion workflow but not the precise store build attendees used, a preinstalled app, a badge firmware image, a flashing/update path, original firmware ownership, a post-event support commitment, or a license for event branding and media. The MIT package license applies to its source code only.
The entry keeps open-source companion software separate from physical-badge firmware, event deployment, trademark/media rights, and any implied image-reuse permission.
Assembly was disrupted when the reflow oven conveyor stopped working; the team externally drove the conveyor motor and tuned the supply around 8.5 to 9 volts to keep production moving.
The record captures the real operational work behind the polished attendee artifact and preserves a useful production failure mode for future badge teams.
The event and repository establish a Security Fest 2026 conference-badge association, but recovered sources do not state ticket inclusion, number of units, recipient eligibility, on-site handoff, or whether every attendee received the artifact.
The record can document a real event artifact without converting the public source trail into unsupported issuance or credential claims.
The quoted badge text says the board is loaded with an Arduino Leonardo bootloader and can be treated as an Arduino clone, but warns that getting everything to work and fit can be finicky.
The compendium records this as a practical attendee caveat rather than an unresolved defect: the badge was intentionally open and modifiable, but not frictionless.
The public source tree and README provide firmware and interface facts but no recovered schematic, PCB design, BOM, battery specification, final board revision, factory-test record, or complete production archive.
Hardware detail remains source-bounded, and the catalogue does not claim that every shipped board matched the repository's documented configuration.
The repository README contains informal reuse language, while its observed GitHub metadata has no formal license classification; no badge photo or raster with the project's required source, reusable-license or permission basis, attribution, and processing notes was recovered.
Source code can be linked as evidence, but no repository media or event imagery is copied into the public catalogue and the badge remains image-free.
The badge's full visual payoff depended on attendees soldering their own LED colors in the conference soldering village.
This is a useful lifecycle record: the badge was partly a shipped object and partly an on-site hardware workshop artifact.
The public package identifies a passive 240×416 four-color e-paper target and NFC transfer path, but no reviewed source identifies the physical controller, display or tag vendor, battery state, board, schematic, BOM, enclosure, lanyard, final artwork, manufacturing run, quality-control outcome, or exact event-unit revision.
The entry describes only the source-backed interface and target profile rather than reconstructing unsupported electronics or treating generic documentation as a final physical specification.
No Security Fest 2023 Gothenburg Skyline 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 Sweden record remains source-backed and image-free rather than copying source-page media, documentation screenshots, event photos, social media, placeholders, or generated approximations.
No Security Fest 2024 Feskekôrka Piano 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 Sweden record remains source-backed and image-free rather than copying source-page media, documentation screenshots, event photos, social media, placeholders, or generated approximations.
No Security Fest 2018 Challenge 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 Sweden record remains source-backed and image-free rather than copying source-page media, documentation screenshots, event photos, social media, placeholders, or generated approximations.
No Flutter & Friends 2025 E-Paper Conference 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 Sweden record remains source-backed and image-free rather than copying source-page media, documentation screenshots, event photos, social media, placeholders, or generated approximations.
No Security Fest 2026 RP2040 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 Sweden record remains source-backed and image-free rather than copying source-page media, documentation screenshots, event photos, social media, placeholders, or generated approximations.
No documentary photo of the original 2022 artifact has been cleared for public reuse.
The source-backed facts remain useful while the catalogue withholds imagery until licensed original photos are curated.
The CTF LED path required desoldering capacitors C1 and C2, replacing them with 22 pF capacitors, and soldering SMD LEDs and resistors at specific locations.
The badge intentionally blurs software play with hands-on hardware rework; the compendium tracks that as a lifecycle/challenge caveat.
The README identifies high-power white/IR and IR-transmitter hardware surfaces, but recovered sources do not provide a final power budget, optical-output characterization, safety test, authorized-use context, or production-specific behavior.
The catalogue records their existence at a high level but does not publish operational configurations or represent them as tested, unrestricted, or universally fitted features.
The current public source set found for this pass describes the badge through later Security Fest badge retrospectives rather than a standalone 2022 build page.
The dossier keeps the 2022 badge discoverable while avoiding chip-level, firmware, app, production, or author claims until primary sources are recovered.
The current build has not cleared a reusable original badge photo from the field writeup or repository.
The record remains source-backed for facts, while the catalogue withholds imagery until a licensed original photo is curated.
Resources
Gothenburg Skyline Badge mirror
article mirror · Readable mirror of the badge writeup, useful for text extraction and corroborating serial/CTF details.
Security Fest 2026 attendee report
attendee corroboration · Contemporaneous attendee report corroborating the hardware-hacking context and crediting Carl Vargklint's badge work; it does not establish universal attendee allocation or assembly.
Security Fest Piano CTF Badge
badge guide · Hackerware guide for LED placement, CTF unlock solder steps, serial monitor settings, and mini-speaker solder points.
The Feskekôrka Piano Badge
badge writeup · Hackster project writeup with story, bill of materials, assembly notes, serial menu, CTF design, photos, and credits.
The Gothenburg Skyline Badge
badge writeup · Hackster project writeup for the Security Fest 2023 UV-printed Gothenburg Skyline badge.
SecBadge BOM
bill of materials · BOM listing the 69x43 mm board's ATmega32U4, USB-A connector, four-position DIP switch, two tactile switches, red/green LEDs, crystal, passives, and ISP header.
NFC data format
conference-badge update protocol · Package documentation identifying the badge as an NFC Forum Type 4 tag using NfcA and documenting the passive image-transfer path. Generic active/Bluetooth material is kept separate from the 2025 event-unit assertion.
Security Fest CTFtime profile
ctf context · CTFtime profile for Security Fest; may require anti-abuse access controls.
Security Fest
event site · Current public Security Fest site for conference-lineage context.
Security Fest
event site · Current public Security Fest site for Swedish conference-lineage context.
friends_badge v0.1.4 source
event-period companion package release · Versioned MIT-licensed Flutter package source that the organizer app locked during the 2025 event period; its description says it controls the Flutter & Friends e-ink conference badge and writes images to e-paper badges.
Security Fest 2018 challenge badge writeup
field writeup · Zeta-Two field report documenting the challenge badge, HID/serial behavior, DIP-switch clue paths, prize flow, and community attribution.
Security Fest 2026 RP2040 pinout reference
hardware reference · Public repository pinout reference for the badge's labelled RP2040 interfaces; it does not replace a schematic, PCB release, or BOM.
Image data format
image-conversion documentation · Package documentation for raw, uncompressed, column-major bitmap data sent to the badge after image conversion.
BadgeSpecification source
implemented target-profile source · The package's sole implemented target profile is `size3_7inchPassiveBWRY`: 240×416, passive, and black/white/yellow/red.
Security Fest 2026
official event page · Security Fest's official completed-event page establishes the May 28-29, 2026 conference at Elite Park Avenue Hotel in Gothenburg.
Flutter & Friends app Friends Badge feature commit
organizer-published conference-app commit · Dated August 30, 2025 source commit that adds the Friends Badge extra, Android/iOS NFC capability configuration, image-selection flow, e-paper conference-badge wording, and write-to-badge action in the organizer-published conference app.
Flutter & Friends 2025 app schedule
organizer-published event schedule source · Immutable conference-app schedule source encoding August 31-September 2, 2025 event activity in Stockholm and registration at Kulturhuset Stadsteatern.
FriendsBadgePage source
participant-facing app interface · Organizer-published page source for the Friends Badge editor: image selection, dither-kernel preview, and the NFC write action are exposed as a conference-app extra.
Security Fest 2026 badge firmware
public firmware repository · Public repository identifying itself as the official firmware repository for the Security Fest 2026 conference badge; it is source evidence, not a formal hardware-production release.
Superminaren profile
publisher identity · GitHub profile identifying the repository publisher Superminaren as Carl Vargklint.
Security Fest 2026 badge repository metadata
repository metadata · GitHub REST metadata records the May 2026 repository creation/push window and no formal repository license classification.
Feskekôrka Piano Badge retrospective
retrospective badge writeup · Later Security Fest badge writeup that helps place the 2022 tram badge in the same Gothenburg-landmark badge lineage.
Gothenburg Skyline Badge retrospective
retrospective badge writeup · Later Security Fest badge writeup mentioning the previous year's fun blinky badge inspired by Gothenburg trams and Rickroll.
SecBadge repository
source · Public hardware repository with board files, schematic/layout assets, firmware directory, and Gerbers for the challenge badge.
friends_badge MIT license
source license · MIT license for the companion-package source. It does not license event branding, a physical badge, original firmware, photographs, screenshots, or conference media.
Security Fest 2026 badge README
technical reference · Repository README documenting the RP2040, memory, LED matrix, front LEDs, buttons, USB, SAO, GPIO, and high-level firmware surfaces.
Sources
GitHub: Superminaren
Retrieved 2026-05-15 · Publisher identity source showing the Superminaren GitHub profile name as Carl Vargklint.
GitHub / Flutter & Friends: BadgeSpecification
Retrieved 2026-05-15 · Primary source for the implemented 240×416 3.7-inch passive black/white/yellow/red e-paper target profile.
GitHub / Flutter & Friends: Flutter & Friends 2025 schedule data
Retrieved 2026-05-15 · Organizer-published source establishing the August 31-September 2, 2025 schedule chronology, Stockholm context, and Kulturhuset registration location.
GitHub / Flutter & Friends: FriendsBadgePage
Retrieved 2026-05-15 · Primary source for the participant-facing Friends Badge interface, image selection, dither preview, and write-to-badge UI path.
GitHub / Flutter & Friends: Image Format
Retrieved 2026-05-15 · Primary source for raw, uncompressed, column-major bitmap output from the companion package.
GitHub / Flutter & Friends: NFC Data Format for Badge Communication
Retrieved 2026-05-15 · Primary source for the NFC Forum Type 4/NfcA description and passive image-transfer protocol. It does not prove physical component choice, final event configuration, or every attendee's use.
GitHub / Flutter & Friends: feat: add friends badge to extras
Retrieved 2026-05-15 · Primary organizer-published, dated August 30, 2025 source associating the public app's Friends Badge editor, NFC configuration, e-ink conference-badge language, and write action with the imminent 2025 event.
GitHub / Flutter & Friends: friends_badge LICENSE
Retrieved 2026-05-15 · Primary MIT-license source for the public package code only; it does not establish image reuse, event media, or badge-hardware rights.
GitHub / Flutter & Friends: friends_badge v0.1.4
Retrieved 2026-05-15 · Primary versioned companion-package source explicitly describing control of the Flutter & Friends e-ink conference badge and image writing over NFC during the event period.
GitHub / znibb: SecBadge
Retrieved 2026-05-15 · Primary open-hardware source for board dimensions, design files, Gerbers, firmware directory, and component evidence.
GitHub REST API: Security Fest 2026 Badge Repository Metadata
Retrieved 2026-05-15 · Repository metadata observed in this audit records a May 2026 creation/push window and `license: null`; the README's informal reuse language is not treated as a formal catalogue image license.
Hackerware: The Security Fest Piano CTF Badge
Retrieved 2026-05-15 · Primary source for serial monitor settings, speaker solder points, and CTF LED/solder instructions.
Hackster.io: The Feskekôrka Piano Badge | Security Fest
Retrieved 2026-05-15 · Primary source for badge story, BOM, hardware, serial interface, CTF, production caveat, photos, and authors.
Hackster.io: The Feskekôrka Piano Badge | Security Fest
Retrieved 2026-05-15 · Supporting source for Security Fest's continuing Gothenburg landmark badge design lineage.
Hackster.io: The Gothenburg Skyline Badge | Security Fest
Retrieved 2026-05-15 · Primary source for design story, hardware components, UV printing, soldering village, serial CTF behavior, and author credit.
Hackster.io: The Gothenburg Skyline Badge | Security Fest
Retrieved 2026-05-15 · Retrospective source for the 2022 tram-inspired blinky badge and Rickroll lore.
JPRalves mirror: The Gothenburg Skyline Badge | Security Fest
Retrieved 2026-05-15 · Corroborating readable copy of the Hackster project text.
Jonathan B. / LinkedIn: Thank you Security Fest and all the speakers and sponsors
Retrieved 2026-05-15 · Contemporaneous attendee corroboration for hardware-hacking interest around the badge and a narrow credit to Carl Vargklint; it does not prove issuance, manufacturing, or every attendee's experience.
Securityfest AB: Security Fest — IT Security Conference, Gothenburg, Sweden
Retrieved 2026-05-15 · Primary event source confirming Security Fest's ninth conference at Elite Park Avenue Hotel on May 28-29, 2026 in Gothenburg.
Superminaren / GitHub: Security Fest 2026 Badge
Retrieved 2026-05-15 · Primary badge source calling itself the official firmware repository and documenting the device's concrete hardware and high-level firmware surfaces.
Superminaren / GitHub: secfest2026badgecode
Retrieved 2026-05-15 · Primary public source-tree record for the badge firmware, repository structure, and its conference-badge association.
Zeta-Two: Security Fest 2018 Challenge Badge & Prize Assembly
Retrieved 2026-05-15 · Primary field source for challenge behavior, HID/serial lore, clue flow, prize context, Weckzen attribution, and Zkylark Electronics thanks.