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?
It’s been a while since the last URU Key update, but the project’s still alive and kicking! Chrome dropped BLE support (ouch), but Windows still plays nice. Plus, I got official docs from Fingerprint Cards (🎉), and even tested URU Key with Windows Hello. Oh—and a new open-source project is coming soon!
I hooked up both the MH-Z19B and CCS811 CO₂ sensors side by side and logged data for a full week. The results? They mostly follow the same trends—but actual readings vary wildly, sometimes by 1000+ ppm. Which one’s accurate? Hard to say without a calibrated reference…
Picked up a CJMCU-811 CO₂ and air quality sensor to compare it with my go-to MH-Z19B. It’s smaller, cheaper, uses I2C, and reacts super fast (you can literally breathe on it and watch the values change). One of my two units didn’t work, though—so quality might be hit or miss.
In Part 2 of my CO₂ sensor project, I set up the MH-Z19b with Arduino and ESP8266 using PlatformIO. Added WiFi-based configuration with my own WiFiConfig library, and used RecurringTask to keep everything responsive without blocking the loop. It’s simple, wireless, and super easy to tweak from your browser!
Hardware is done! After months of prototyping, I finally finished the compact 40×15mm URU Key device—complete with ESP32, fingerprint scanner, security chip, LiPo battery, and USB-C. It’s basically a fitness tracker… but for secure authentication. Now onto the software (and maybe a proper case 😅).