Hi, a few months ago I decided to revival one of my old Sinclair QL,
I found this page http://www.deblauweschicht.nl/tinkering/qlkeys1.html that explain how to transform a QL into an USB ~modern~ keyboard....
But I didn't wanted stop there, so I include also a raspberry inside !
First I had to decode the original keyboard lines, used a 74HCT154 line decoder and an arduino micro to do that.
(I had to unsolder legacy keyboard membrane connectors, a very long & painfull operation)
code source will come soon ...
Then I used the Arduino to behave as an USB HID Keyboard + I kept a couple of lines to make a serial kbd input for any other device (like another arduino)
Then I insert another Arduino (UNO) to act as a serial TV OUT (via RCA)
So, @ this point : I have a serial keyboard & a serial tv out :
I can ,by this way : plug a third arduino that can run tiny BASIC for example ... (w/o having to manage I/O libraries !! )
Then, I added my raspberry ... to have a ~modern~ standalone computer (than can do retro emulation ;-) )
I made a junk wiring with ext. powered USB HUBs - then It can be all power supplied with a single 5v 2A DC adapter
Now I can choose what computer mode I want to run :
The final result is a dual mode "computer", with linux, wifi, powerfull CPU or a ready to use terminal for my other experiences...
See you ...