How does a computer keyboard work? - Explain that Stuff
Some keys on my laptop aren't working properly, including Z, 7, F5, F8, Fn etc. Can some key combinations be used to type those without using an on-screen keyboard? - Quora
USB keyboard controller and pi zero - Raspberry Pi Forums
How To Build A Simple Keypad-Operated Switch
Building your own keyboard (from scratch) | by w4ilun | Medium