Hackerhotel 2023

The Hackerhotel 2023 badge, the Anesidora Mk1, is a puzzle badge built around a RP2040 microcontroller. The board is artwork first: the copper and the soldermask draw a cracked stone tablet in lapis blue and gold, in the style of an ancient grave marker, and the electronics sit in and around it.

The badge was the key to the puzzle hunt at the event. Clues were hidden in binary on the lanyards and on markers around the hotel, and the badge itself served a text adventure over its USB serial port. Attendees who solved everything received a physical amulet.

Hardware

• RP2040 microcontroller
• A row of buttons and LEDs along the bottom of the board, laid out as the data and address lines of a small computer
• USB-C for power, serial and firmware updates
• CR2032 coin cell for use away from a cable, selected with the BAT/USB switch on the top edge
• Artwork in the copper and soldermask layers of the PCB itself

Firmware

The firmware is written in MicroPython. Updates ship as a .uf2 file, which the RP2040 bootloader takes without any tools:

1. Download the .uf2 from the firmware update repository.
2. Set the switch on the top of the badge to USB and connect it to your computer.
3. Hold BOOTSEL, press RESET, then release both.
4. Copy the .uf2 file to the RPI-RP2 drive that appears.
5. Wait for the copy to finish, then press RESET.

If the badge does not run on battery, the contacts of the battery clip are usually the cause. The documentation repository explains how to bend them back.

Repositories

The badge was developed under the Anesidora Corporation organisation on GitHub:

• hh2023hardware — KiCad design files
• hh2023firmware — the badge firmware
• hh2023firmwareupdate — released .uf2 updates
• hh2023documentation — visitor instructions, location markers and an FAQ

More reading

• Hacker Hotel 2023 Had A Very Cool Badge on Hackaday

The team

• Pim: Team lead, hardware and software development
• Sake: Challenges
• Nikolett S.: Artwork