While working on the URU Card project, I realized just how practical the credit card form factor really is—so I redesigned URU Key into URU Card Pro. It now fits in a wallet, runs on an ultra-thin Li-Ion battery, and includes a tiny OLED display for feedback. Same secure guts, much better usability!
I added a tiny capacitive touch keyboard to the URU Card using the MPR121 chip—and it works great! The PCB has 12 touch pads, the setup is dead simple with I2C and the Adafruit library, and best of all… no debouncing needed. Smooth and responsive UI, just like I hoped.
Got a fresh batch of URU Card PCBs, and this time I used them to build a full hard shell case—just by stacking boards together. No 3D printing needed! I also switched to a PCB antenna (zero cost!) and prepped the layout for a future USB interface with the FT260 chip. It’s compact, wallet-friendly, and fully functional.
Picked up one of those common UART fingerprint modules? I did too. Turns out, it’s not just a scanner—it does internal matching with an onboard STM32 chip. I tested it with an ESP32 board, wrote up a simple Arduino sketch, and it works surprisingly well. Full pinout, usage, and code included!
I finally built myself a universal programmer for ESP8266 and ESP32 boards using a CP2102 chip and a bunch of connectors. It’s simple, cheap, and works with everything—from ESP-01 to my custom URU Card. Full schematic, photos, and files are in the repo if you want to build one too.
Finally, a working BLE-based FIDO2 authenticator on Arduino! The URU Card project now supports basic credential creation and authentication via ESP32. Still early-stage (with hardcoded keys for now), but it’s enough to pass WebAuthn tests in Windows—and it’s open for everyone to try and build on.
I finally tried using a stencil for soldering SMD components—and wow, total game changer. Ordered my URU Card PCBs + stencil from PCBWay, applied solder paste, placed the parts, hit it with hot air… and boom, working device in under 30 minutes. Bonus: I filmed the whole process in a quick tutorial!
After a lot of requests to open-source URU Key, I’m starting a new project—URU Card! It’s a wallet-sized, open-source FIDO2 authenticator with an OLED screen, touch keyboard, and ESP32 brain. No biometrics (for now), but secure, DIY-friendly, and easy to build with Arduino libraries. Want to join in?