A PCB business card meant to be plugged into a computer and emulate an HID input device. The first use case was as a macropad, but since it can do anything with HID, it can also in theory be a:
pentesting tool (like the rubber ducky)
MIDI musical instrument
Possibly a capacitive proximity sensor (I'll have to see if the hardware is capable of that)
Small USB drive

The NFC EEPROM is a ST ST25DV04 4kbit I2C reprogrammable NFC EEPROM. This gives the card the ability to store a small amount of data like contact information. Or perhaps it could be used to send the RP2040 new macros.

There's also an addressable LED (argbled) onboard as well as a physical button (for all your clicking needs).

Some (slightly unnecessary) features added in V2
- FUNtenna (inspired by CNlohr's RF bitbanging) to possibly send weak FM radio signals
- light sensor (uhhh it was cheap)
- LIS3DH accelerometer (also cheap and optional. Could allow the card to be used as a tilt-based mouse)