JawnCon 0x3 · United States · 2026

JawnCon 0x3 Calculator Badge

ATmega328P calculator kit badge with DTMF tones, hidden games, a badge-to-badge link, and an in-event firmware fix

The JawnCon 0x3 badge, documented on JawnCon's official badge page ahead of the October 16-18, 2026 conference at Arcadia University. The JawnCon0x3 Badge is a four-digit, seven-segment calculator kit built around an ATmega328P-P with a 16-key keypad. Every key plays a touch-tone (DTMF) pair, typed codes unlock hidden games, a USB-serial menu renames the badge and shows high scores, and a wired serial link lets two badges introduce themselves and count links. A 20-pin edge connector lets attendees plug in their own hardware. The page has attendees assemble the kit at the JawnCon soldering station. During the conference the official homepage said this year's badge had sold out and published a fixed firmware image, with a reprogrammer in the Chillout space. Kit counts and how many attendees received one are not published.

JawnCon United States Pennsylvania Philadelphia Glenside Electronic Badge Kit Badge Firmware Update ATmega328P Seven-Segment Display Calculator DTMF Edge Connector Retro Technology North America No Image

EventJawnCon 0x3

SeriesJawnCon

LocationArcadia University Commons Building, Glenside, Pennsylvania

CountryUnited States

People

Authors & Credits

event organizer and badge-page publisher

JawnCon, LLC

Publisher of the JawnCon0x3 Badge manual, BOM, build notes, case files, and firmware image; the pages do not name an individual badge designer.

Source

in-event firmware bug fixes

Jorj

Named on the official homepage on October 17, 2026 as having found and fixed bugs in the badge. Only the first name is given there.

Source

Why It Mattered

It continues JawnCon's retro-technology badge theme after the 0x1 Hayes-style modem badge, and its official pages publish the complete user manual, the bill of materials, and an in-event firmware image while leaving schematic, firmware source, and kit counts open.

Hardware

The official bill of materials lists an ATmega328P-P microcontroller with a crystal and two 22 pF capacitors, a CC56-12CGKWA four-digit seven-segment display driven through a 74HC595 shift register and four PN2222A transistors, a PCF8574 I/O expander scanning 16 push buttons through 16 1N4148W diodes, a 20-pin edge connector (J1), four single-pin connectors, 220 Ω segment resistors, 4.7 kΩ and 2.2 kΩ resistors, and a 100 nF decoupling capacitor. The build notes recommend soldering resistors, diodes, ICs, crystal, capacitors, buttons, then the display, testing on the station's cable, and then fitting the power pack. JawnCon publishes STL and 3MF files for a printed front and back case held by M3x6 screws. No schematic, PCB files, or production count are published.

Software & Apps

The manual describes a calculator limited to four digits (EEEE on overflow or divide by zero, double = to clear), DTMF tone pairs on the digit keys, a single 2600 Hz tone on = and a 1700 Hz plus 2200 Hz burst on the decimal key, and a three-second static-to-text boot animation showing customizable boot text (JAWN by default). Typing 1337, 1338, or 0203 followed by = starts Higher or Lower, DTMF Tone Recall, or Hex Recall, a further unlisted game needs a friend to find, and the high-score list shows one LOCKED entry. A 115200-baud serial menu sets the boot text, shows saved high scores, and starts a 9600-baud badge-to-badge link (link RX on pin 15 and TX on pin 16 in the October 19 revision of the manual; the October 15 copy named pins 10 and 8) that exchanges boot texts and keeps a permanent link count. On October 17, 2026 the official homepage said Jorj had found and fixed bugs in the badge and published jawncon-badge.hex, an Intel HEX image of 21,462 bytes for the AVR. Its strings contain the badge menu, boot-text validation, high-score labels for Vault, Hex Recall, DTMF Recall, and Higher-or-Lower, a keypad-not-found error, and the link prompts. Vault does not appear in the manual and is presumably the hidden extra game it hints at. No firmware source is published.

Lore

JawnCon 0x3 ran October 16-18, 2026 at Arcadia University's Commons Building, starting a day earlier than past editions. The badge page signs off with Happy hunting. On October 17 the homepage told visitors the badge had sold out, that previous years' badges would serve as admission, and that attendees could reprogram their badges with Jorj's bug fixes at the Chillout space. Hackaday's October 13, 2026 preview by Tom Nardi describes the badge as looking like a simple handheld calculator, available in assembled or kit form and distributed as a bare PCB with printable case files, and notes that attendees can also make custom ID badges on a pair of Zebra printers.

Lifecycle

Add-ons & Upgrades

badge games official manual and firmware image

Hidden calculator games

Typing 1337, 1338, or 0203 followed by = starts Higher or Lower, DTMF Tone Recall, or Hex Recall, with high scores saved across power cycles; the manual says at least one more game is hidden, hinted by a LOCKED high-score line, and may need a friend. The October 17 firmware image lists a fourth high-score line, Vault - fewest attempts to crack.

Compatibility: JawnCon 0x3 Calculator Badge

Source

badge interaction official manual

Badge-to-badge serial link

From the serial menu, two badges joined by crossed TX/RX (pin 16 to pin 15 in the October 19, 2026 manual, after pins 10 and 8 in the October 15 copy) and ground handshake at 9600 baud, show each other's boot text, and add to a permanent link count; the connector style is left to the builder, and something may change after the first link.

Compatibility: Two JawnCon 0x3 Calculator Badges

Source

case official print files

3D-printed badge case

Front case STLs for single- and multi-colour printers and a back-case 3MF with integrated supports, fastened with M3x6 screws.

Compatibility: JawnCon 0x3 Calculator Badge

Source

expansion connector official BOM

20-pin edge connector

The board's J1 20-pin edge connector lets attendees slot in their own hardware; no pinout for it is published.

Compatibility: JawnCon 0x3 Calculator Badge

Source

firmware update official in-event notice

Chillout-space reprogrammer and firmware fix

On October 17, 2026 the official homepage said Jorj had found bugs and fixed them in the badge, and invited attendees to reflash at a reprogrammer in the Chillout space or to load the published jawncon-badge.hex themselves. The notice does not list the bugs.

Compatibility: JawnCon 0x3 Calculator Badge (ATmega328P)

Source

Operational history

Issues & Camp Impact

design and firmware archive gap note

JawnCon publishes the bill of materials, manual, case files, and since October 17, 2026 a firmware HEX image, but no schematic, PCB files, firmware source, or badge designer credit, and the case files are marked © 2026 JawnCon, LLC without a reuse licence.

The record cites the official manual for behaviour and the HEX image for its strings, and leaves circuit details beyond the BOM, firmware source, and reuse rights open.

Confidence: official badge page
Status: BOM, manual, and firmware image published; schematic, PCB, and firmware source absent
Timeframe: as of 2026-10-21
Source note: JawnCon badge and case printing pages and jawncon-badge.hex, checked 2026-10-21.

in-event firmware fix low

During the conference JawnCon announced that Jorj had found and fixed bugs in the badge and offered a reprogrammer in the Chillout space and a downloadable HEX image. The notice does not say which bugs, and the manual's link pins changed from 10 and 8 to 15 and 16 in the October 19 revision.

Badges not reflashed during the event may still run the original firmware; owners can load the published image themselves.

Confidence: official homepage notice
Status: fix published; bug list absent
Timeframe: October 17, 2026
Source note: JawnCon homepage and badge page, checked 2026-10-21.

kit and assembled form discrepancy note

The official build notes have attendees solder the kit from parts drawers at the JawnCon soldering station, while Hackaday says the badge comes in assembled or kit form and is distributed as a bare PCB.

Both statements are kept with attribution until post-event sources show which forms were actually offered.

Confidence: official badge page versus media preview
Status: unresolved
Timeframe: pre-event
Source note: JawnCon badge page and Hackaday preview, checked 2026-10-15.

missing rights-cleared image note

No JawnCon 0x3 badge image is published because the official pages show no badge photo with a reuse licence and the Hackaday preview's images are not licensed for reuse.

The entry stays image-free rather than copying preview or case-printing images.

Confidence: local project policy
Status: needs licensed original replacement
Timeframe: current catalogue build
Source note: badge.gallery image policy; JawnCon badge and case pages; Hackaday preview.

post-event distribution gap note

The official homepage said on October 17, 2026 that this year's badge had sold out and that previous years' badges would serve as admission, so not every attendee held a 0x3 badge. No source gives the number of kits, how many were assembled on site, or whether any were sold assembled.

The record treats the badge as distributed at the event without asserting a quantity or attendee-wide availability.

Confidence: official in-event homepage notice
Status: sold out; count unpublished
Timeframe: post-event as of 2026-10-21
Source note: JawnCon official homepage, rechecked 2026-10-21.

Resources

JawnCon 0x3 Kicks Off In Philadelphia This Friday media preview · Hackaday preview by Tom Nardi, October 13, 2026, describing the calculator-style ATmega328P-P badge, its DTMF generator, games, badge linking, edge connector, assembled or kit options, bare-PCB distribution, printable cases, and on-site Zebra ID printers. JawnCon 0x3 badge case printing official case files · Official STL and 3MF files for single- and multi-colour front cases and a supported back case, with orientation and bridging notes and M3x6 screws; marked © 2026 JawnCon, LLC without an open licence. JawnCon 0x3 official site official event page · Official site for the October 16-18, 2026 conference at Arcadia University's Commons Building. The October 15, 2026 check still read Badge information coming soon! on the homepage. The October 21, 2026 recheck found the MOTD updated on October 17, during the conference: this year's badge has sold out, previous years' badges serve as admission, and Jorj has found and fixed bugs in the badge, with a reprogrammer in the Chillout space and a firmware download. The page still carries the TICKETS ON SALE NOW! link and has no wrap-up. JawnCon0x3 Badge: User Manual official badge manual and BOM · Official badge page with the user manual (calculator, tones, secret game codes, serial menu, badge-to-badge link wiring), the full bill of materials, and soldering-station build instructions. The October 19, 2026 revision gives the link wiring as RX on pin 15 and TX on pin 16. jawncon-badge.hex official firmware image · Intel HEX firmware linked from the official homepage on October 17, 2026 as the fixed badge code that attendees could load themselves or flash with the Chillout-space reprogrammer. 60,396 bytes as text and 21,462 bytes of AVR program data, SHA-256 bc1250a87f4d7acfb1601d1c1cd9c998d7e4c5395213caf2c3fe06fb87d4249d, served with an October 17, 2026 last-modified date. No source or licence accompanies it.

Sources

Hackaday: JawnCon 0x3 Kicks Off In Philadelphia This Friday Retrieved 2026-10-15 · Secondary pre-event media source corroborating the ATmega328P-P calculator badge and adding that it comes assembled or as a kit and is distributed as a bare PCB. JawnCon, LLC: JawnCon 0x3 Retrieved 2026-10-21 · Primary official source for the October 16-18, 2026 dates and the Arcadia University Commons Building venue. The October 17, 2026 MOTD, written during the conference, says the badge sold out, accepts previous years' badges as admission, and offers Jorj's firmware fix through the Chillout-space reprogrammer; it is the basis for marking the edition completed. It gives no badge count. JawnCon, LLC: JawnCon0x3 Badge: User Manual Retrieved 2026-10-21 · Primary official source for the badge's functions, game codes, serial menu, link protocol and pinout, bill of materials, and kit build process. The October 19, 2026 revision corrects the link pins to 15 (RX) and 16 (TX). It names no designer and publishes no schematic. JawnCon, LLC: jawncon-badge.hex Retrieved 2026-10-21 · Primary official firmware artifact, inspected locally: an AVR image whose strings include the badge menu, boot-text rules, high scores for Vault, Hex Recall, DTMF Recall, and Higher-or-Lower, the keypad-not-found error, and the badge-to-badge link prompts. It documents the fixed firmware, not what each badge shipped with. JawnCon, LLC: JawnCon 0x3 badge case printing Retrieved 2026-10-15 · Primary official source for the printable case files and screws; it establishes the case design, not its distribution.