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.