This variant is for IBM 4704 keyboards, aka 'kishsaver' class model F keyboards, like F107, F50, F62, F77 This variant is not 100% compatible with the https://www.modelfkeyboards.com/ recreations of the F62/F77, because the pin pitch is different, although it is electrically compatible with those too, if one decides to wire it up with individual wires.
For other variants see:
- https://github.com/purdeaandrei/SMDModelFController/tree/extra_columns
- https://github.com/purdeaandrei/SMDModelFController
- https://github.com/listofoptions/TH-XWhatsIt
This project is based on the Through-hole xwhatsit by listofoptions, which is un turn based on the capsense controllers by XWhatsIt (Tom Wong-Cornall). original liscencure holds, as well as CERN OSH (compatible license).
original implementation of Tom Wong-Cornall's controller documented here
http://downloads.cornall.co/ibm-capsense-usb-web/ibm-capsense-usb.html
Working theory of operation is under the previous link.