How do I install a fingerprint reader on Lenovo ThinkPad?

I tried both Fingerprint Gui and FPrint in my Thinkpad W550S. Fingerprint Gui had a nice interface, but was pretty unstable on the login page and sudo and constantly crashed.

FPrint seems more simple, but works very well:

For Ubuntu 20.04 or greater:

sudo apt install libpam-fprintd

For Ubuntu 16.04 or greater:

sudo apt install libpam-fprintd fprint-demo

For Ubuntu 15.04 or less

sudo add-apt-repository -y ppa:fingerprint/fprint
sudo apt-get update
sudo apt-get install libfprint0 fprint-demo libpam-fprintd gksu-polkit

After that, you can test it by running fprint_demo and save the fingerprint with fprintd-enroll. This will automatically make your login screen require a finger swipe instead of a password.

[Update] In some cases you also may need to run:

sudo pam-auth-update

to activate fingerprint reader for elevated privileges for example with sudo

Fprint worked perfectly on a Lenovo Thinkpad X1 Carbon under Ubuntu 14.04. I strictly followed the instructions :

sudo add-apt-repository -y ppa:fingerprint/fprint
sudo apt-get update
sudo apt-get install libfprint0 fprint-demo libpam-fprintd

and finally saved my fingerprint with fprintd-enroll. I can now login and validate my sudo access with a finger swipe !!

On my Thinkpad X220, I had to enable the fingerprint reader in BIOS (tap F1 repeatedly after starting the computer).

After that, fprint_demo works in the sense that it runs, but it fails to read any fingerprint data ("Bad scan. Please remove your finger before trying again.").