“This set of instructions allows you to fabricate your own keyboard controller using old keyboards for the cost of some wire, solder and a piece of wood.
These controllers have been used in my MAME and Virtual Pinball projects.
See Virtual Pinball Instructable https://www.instructables.com/id/Virtual-Pinball-M…
See Camel Racing Instructable https://www.instructables.com/id/Camel-Racing-Arab…
I have used old USB and PS2 keyboards that were intended for disposal. Keyboards that were dirty or had broken keys were good for my project as all I need is the small circuit board inside.
The following set of instructions demonstrates how to make a controller from an HP PS2 keyboard.