It is sad, but not everything went smooth during my experiments with fingerprint scanners. I have desoldered fingerprint scanner from the GROW R300 device wanting to find a way to connect it to the MCU directly.
Unfortunately the pad arrangement on the bottom side does not match any of the scanner datasheets I have found so far. And at the moment I have no idea how to connect it. Definitely I will continue my searches but I guess purchasing scanner of other kind will be a much better idea.
On the other hand I have decided to make custom development board for the authenticator device. It will feature ESP32 Pico D4 microcontroller, ATECC508a security chip, few LEDs and connectors for programming and connecting UART fingerprint scanner.
The design is not ideal but as a first step towards making my own authenticator it should be enough. I am going to improve it step by step until I have working device.
So, the boards and chips are ordered and I’m waiting for the delivery.