While working on the side project URU Card - the open-source authenticator device in the form-factor of a regular credit card - I have noticed that it is way more suitable for daily use. The device like this can be carried around simply in the wallet together with other credit cards.
So, I have redesigned the device in this format. The biggest challenge I had was the power source. Luckily I could discover the ultra-thin lithium battery powerful enough, and it fits perfectly in the space between the logic board ad back cover.
One more addition to the user experience - a tiny OLED display. It is more informative than simple LEDs in the previous version of the device so I am going to keep it in the design.
Other than that, the device features the same set of core elements - ESP32 Pico D4 microcontroller, ATECC508A security element and the FPC1020 fingerprint scanner.
The test utility shows that all the elements work properly and the device is able to perform authentication tasks exactly as the previous version.