Fingerprint sensor - further information please

I am interested in the Fingerprint sensor sold by “Core” at . I understand that one can connect the module via the GPIO’s uart equivalent connection or via a uart-to-usb connector.

My questions on this module are:
(1) where are the fingerprints stored?
(2) Can the fingerprints be transferred to a drive or database?
(a) a nasty person could hack off the sensor and removed the fingerprints.
(b) want to be able to ‘flush out’ fingerprints from the module to a database that a nasty person cannot access.
© want to be able to do analysis of fingerprints.

Thank you,
Anthony of exciting Belfield

Hi Anthony!

From reading the product wiki and the datasheet it looks like the fingerprints are stored on the device and not on an external drive. I’m not sure if its possible to transfer them to another device but it seems likely. Although its technically possible that someone could hack the device and remove fingerprint data, I think that it would be nearly meaningless data. The fingerprint reader stores the fingerprints as lines of code that it then interprets. You would not be able to use a stored fingerprint data from this device anywhere else.

If you are looking to compare fingerprints, this device doesn’t take an image so much as it converts a fingerprint into a password. You will need to write some interesting code to do any comparisons. I think you ought to read through the wiki and the datasheet before going down that path:

Good luck with your project! let us know how it works out!

Dear Stephen,
Thank you for reply and the links to the datasheet/manual. It appears that the SEN0188/zfm-20 by Zhientech modules and manuals are very similar to the R307, R308 made by Hangzhou Grow. Even the manuals have a similar structure and organization. If you look carefully at the manual’s illustration, you will see not only the UART wiring, but an unsoldered USB 2.0 connector at the back of the camera module.

Testing the module on Windows: The Adafruit website, the supplier of the fingerprint module have a Windows program to test the fingerprint module at from Core site You will need a UART-to-USB converter sold by ‘Core’ or

However, I’m ‘‘nerdy’’ and the Windows example does not have the source code. The datasheet/manuals that were described in the first paragraph discuss bytecode instructions to: switch on/off leds, store & erase templates, search&erase&store images .

My aim, amongst others is to understand the operations in python, in particular applying it to the RPi’s GPIO or RPi’s USB AND through Windows via the USB.
I could not find a straightforward code for the RPi or Windows in Python.

However, for the GT-521F52 scanner which is a completely different model to the zfm-20, R307 and R308, there is Python and Java code implementations According to these authors, it was a matter of studying the datasheets and applying it to Python and Java implementations.

I am not sure whether I can apply it to the datasheet for the zfm-20, r307 and r308. Suppose I don’t use the RPi’s GPIO which requires the GPIO python module for the RPi, I could use the USB connection via a uart-to-usb interface for both the RPi and Windows and apply it to the UART.

Any hint would be appreciated,
Thank you,
Anthony of Belfield

I wish I had a definitive answer for you, but many times components like this are manufactured in the same factory, and are re-branded by different distributors. Its entirely possible that they would be compatible but I can’t promise you that it would be. It think the best way to find out is to try it out!

Let me know what you find!