FPC1020 Fingerprint Scanner - detecting finger presence

FPC1020 Fingerprint Scanner - detecting finger presence

Back to FPC1020 driver work! I fired up an ESP8266 with Arduino to detect finger presence using the scanner’s built-in sensor matrix. It’s simple, fast, and could help optimize image capture—or even act like a button or gesture detector. Full example code and visuals inside!

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URU Key - fully autonomous prototype

URU Key - fully autonomous prototype

It’s official—URU Key is now a real, standalone device! I added the custom power board, used spring-loaded pins for easy firmware updates, and screwed everything together into a compact 35×20×10mm unit. Hardware’s basically done—now it’s time to dive deeper into the firmware, especially the biometric side.

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How to measure battery level with ESP32 microcontroller

How to measure battery level with ESP32 microcontroller

Figured out how to measure battery level on the URU Key using a simple voltage divider and some clever GPIO control. Threw in some ESP32 ADC math to convert readings into a nice 0–100% percentage—and even blink a red LED if the battery’s running low. BLE support coming too!

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URU Key - making decision on power source

URU Key - making decision on power source

Next step: power! I explored both CR2032 coin cells and tiny rechargeable LiPo batteries for the URU Auth device. Settled on a rechargeable setup with a TP4054 charger and USB-C—compact, convenient, and way more user-friendly. Bonus: added battery level monitoring and auto power-off to keep things efficient.

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URU Key - an ESP32 FIDO2 Authenticator

URU Key - an ESP32 FIDO2 Authenticator

Everything’s finally coming together! I combined the ESP32, fingerprint scanner, and ATECC508A security chip into a single board—the first real version of my own FIDO2 Authenticator: URU Auth (You Are You). It’s handheld, it lights up, and it’s so close to being fully autonomous. Time to tackle power and fingerprint recognition!

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Using ATECC508A Cryptographic co-processor with ESP32

Using ATECC508A Cryptographic co-processor with ESP32

Time to tackle the ATECC508A crypto chip! I started building an ESP32 component library to use it in my FIDO2 Authenticator. One chip gave me trouble, but another worked perfectly. Lots of I2C fun, ECC signatures, and some helpful inspiration from SparkFun’s Arduino library. One step closer to full hardware-based security.

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FPC1020A* Fingerprint Scanners

FPC1020A* Fingerprint Scanners

Finally got my hands on the FPC1020 fingerprint scanners! These things are tiny, SPI-based, and perfect for a built-in solution. I built test boards, hooked them up to a NodeMCU, and wrote a basic Arduino sketch to read the hardware ID. Next step: integrating with the main authenticator project!

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