The directions below are how to setup the GNU/Linux Fingerprint TPE-F4500 on Kubuntu systems. The information pertains to at least Kubuntu 25.10, but likely also works on Kubuntu 24.04, 24.10, and will possibly be needed for future releases until full support is integrated (and may be partially needed for instruction on how to enroll the fingerprint in the first place thereafter).
It's highly recommended to watch Watch the video demonstration.
Currently the current SDDM login manager (as of Kubuntu 25.10) requires a manual trigger (like pressing Enter on the empty password field) to activate the fingerprint reader. This is a known limitation. SDDM does not natively support automatic fingerprint sensor polling. The PAM module pam_fprintd.so only activates when the authentication process is initiated, which requires user input. Press Enter on the empty password field to trigger the scanner. This is the standard behavior across most Linux distributions using SDDM
Steps to enable fingerprint reader at login:
1. Open a terminal (click on the KDE menu in lower left corner, search for konsole, and open konsole)
2. Type the following line into the terminal and hit enter:
sudo nano /etc/pam.d/sddm
3. Copy and paste the below two lines into the terminal at the top:
auth sufficient pam_fprintd.so max_tries=3 timeout=10
auth [success=1 new_authtok_reqd=1 default=ignore] pam_unix.so try_first_pass likeauth nullok
4. Hold down the ctrl key and while holding down this key tap the x key on the keyboard
5. You will be asked to save the file (ie "Save modified buffer?"), tap the y key to confirm you do. Then hit the enter key on "Write to File: /etc/pam.d/sddm"
6. Now enable the fingerprint reader by running the following command and checking the box that says "Fingerprint authentication" using the space bar and then hitting tab to select the OK box and hitting enter:
sudo pam-auth-update
7. Click on the KDE menu in the lower left corner, type in users, then open Users app when it appears in the search results
8. Click the Configure Fingerprint Authentication... button
9. Click the Add button
10. Select the right thumb on the hand on the screen (if right handed)
11. Place your thumb on the fingerprint reader straight on
12. Repeat with the thumb a little off to the right side
13. Repeat with the thumb a little off to the left side
14. Repeat with the thumb a little over the top of the fingerprint sensor
15. Repeat with the thumb a little under the top of the fingerprint sensor
16. If you haven't completed the process place your thumb straight on again
17. Restart sddm by entering the command below followed by hitting enter or otherwise reboot the computer
sudo systemctl restart sddm