Flutter & Friends 2025 · Sweden · 2025
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.
People
The Flutter & Friends GitHub organization publishes both the conference-app commit and the friends_badge companion package. This credit does not assign physical badge design, manufacture, allocation, firmware, or image-rights ownership beyond the published sources.
SourceThe public friends_badge initial commit identifies Lukas Klingsbo as its author. This credit is limited to the companion-package source trail and does not assign physical-badge design, manufacture, event allocation, firmware, or media rights.
SourceThe organizer-app commit that adds Friends Badge to the extras is authored by Johannes Pietilä Löhnn. The source does not assign individual ownership of every hardware, firmware, production, or event-delivery role.
SourceThe organizer-app commit credits Felix Angelov as co-author. This is limited to the named conference-app source contribution, not an assertion of physical-badge authorship or image-rights ownership.
SourceIt adds a developer-conference badge whose public mobile-app source makes the personalization workflow unusually concrete: a participant-facing Flutter interface, local image processing, e-paper preview, and NFC write path. The catalogue preserves that useful software trail without turning a conference-app feature into a universal allocation claim, a complete hardware reconstruction, or a license for event media.
The public companion package's sole implemented `BadgeSpecification` target is a 240×416, 3.7-inch passive black/white/yellow/red e-paper configuration. Its NFC documentation identifies the badge as an NFC Forum Type 4 tag using NfcA technology for image transfer. The public sources do not identify the event unit's controller, e-paper vendor, tag IC, battery, enclosure, lanyard, PCB, schematic, BOM, production run, final artwork, or final physical revision. Generic package documentation also describes active/Bluetooth-capable badge protocols, but that is not treated as proof that the 2025 Flutter & Friends unit had a battery or Bluetooth hardware.
The organizer-published app added a Friends Badge extra with image selection, dithering-kernel preview, and an NFC write action. The associated MIT-licensed `friends_badge` package says it writes images to e-paper badges, detects the supported badge specification, crops/resizes and dithers images, and transfers raw column-major bitmap data through its NFC protocol. The source is evidence of a public companion software workflow, not a record of a particular App Store build, installed version, all-user deployment, original badge firmware, or post-event support service.
The same organizer-published app schedule encodes the August 31-September 2, 2025 Flutter & Friends conference at Kulturhuset Stadsteatern in Stockholm. The Friends Badge feature landed on August 30, immediately before the event. That chronology supports a conference-linked customization surface but does not record individual use, a badge-hacking session, issuance counts, access-control role, or the physical fate of event units.
Source-backed hardware metadata
Structured technical signals seeded from public badge documentation, repositories, schematics, firmware notes, or event evidence. These fields are designed for filtering, API use, repair planning, preservation, and future Companion Gear matching.
The organizer-published August 30, 2025 conference-app commit describes the target as the e-ink conference badge and adds a participant-facing badge-write interface.
Signal sourceThe event-period v0.1.4 companion package documents NFC Forum Type 4/NfcA badge communication for the passive image-transfer path.
Signal sourceThe event-period v0.1.4 companion package's implemented target profile is a 240×416, 3.7-inch passive four-color e-paper badge configuration.
Signal sourceRepair, preservation, and legal lab context
Parts, tools, and supplies that match this badge's documented hardware, protocols, or preservation needs. These are category-level recommendations, not compatibility guarantees.
Cards and tags for legal lab use, owned test cards, documentation, and protocol exploration.
This badge has documented NFC/RFID or card-protocol signals. Matched technical signals: NFC.
Vendor link · selected for technical relevance
Display modules and related parts for repair and preservation planning.
This badge has a documented display signal. Matched technical signals: E-paper.
Vendor link · selected for technical relevance
Passive tools for non-invasive NFC field presence checks and documentation.
Field detector cards can help document NFC field behavior without modifying the badge. Matched technical signals: NFC.
Vendor link · selected for technical relevance
Headers, sockets, and connector supplies for display repair or replacement work.
Display headers and connectors are useful for repair and preservation planning. Matched technical signals: E-paper.
Vendor link · selected for technical relevance
Storage and handling supplies for RFID/NFC cards used during badge documentation.
Useful for storing and labeling owned NFC/RFID test cards used during badge documentation. Matched technical signals: NFC.
Vendor link · selected for technical relevance
Lifecycle
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.
SourceThe package crops, resizes, and dithers an image before sending raw, uncompressed, column-major bitmap data to the documented badge target.
SourceThe 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.
SourceThe 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.
SourceThe 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.
SourceOperational history
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 catalogue records a factual event-linked electronic badge and companion workflow without upgrading it to an all-attendee entitlement, admission credential, or distribution ledger.
The entry keeps open-source companion software separate from physical-badge firmware, event deployment, trademark/media rights, and any implied image-reuse permission.
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.
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.