This is the button / keypad schematic only.
Other parts I have to draw yet. Had to add some to this drawing to make it complete and compliant to how the actual hard ware is now.
Had only a few scribbles on paper rest i build from top of my head.
It's a simple switch matrix connected to the two input registers of the printer port.
Also available for tinycad program.
(Maybe also other cad's but i dunno. never tried that)
keypad schematic CAD file
I'll post the LED schematic and IRsensor asap.