Really nice work. I believe you are missing the oportunity to put that TI keyboard to work WITHOUT touching anything from the "real" hardware. Do you know the Soarer's Converter for matrix keyboards? https://geekhack.org/index.php?topic=50437.0;all For a Raspberry guy, an arduino-based board would be just a walk in the partk. I´ve done myself with an old and broken TI and it works perfect!! Let me know if you need any help with the configuration of keys. I've pulled up a cool config having almost any PC keystroke in the "tiny" TI keyboard.