This video by Frank Adams shows how to make a USB laptop keyboard controller:
This video and “Instructable” describe how to make a USB controller for a laptop keyboard. I designed a circuit card for a Teensy LC or 3.2 that connects to a keyboard FPC cable with up to 34 pins on a 1mm or 0.8mm pitch.
[Frank Adams] liked the keyboard on his Lenovo ThinkPad T61 so much that he decided to design an adapter so he could use it over USB with the Teensy microcontroller. He got the Trackpoint working, and along the way managed to add support for a number of other laptop boards as well. Before you know it, he had a full-blown open source project on his hands.