This is about my (mahjongg's) clone of the Sinclair ZX81, which design is now finished, although I'm planning a much simpler (to build) 4-chip version where I pour the logic contained in some 24 SMT chips in a replica-ULA based on a small FPGA, (on a daughterboard emulating a real ULA, with the same 40 pin pinout as the real ULA, so its really a replacement ULA) while the rest will be like a modern re-imagening of an original ZX-81, just with far more RAM, and a better keyboard, and USB power and composite video instead of RF, to name a few improvements).
Previously (in 2014) I called my first ZX-81 clone the ZX-14, but I didn't manage to finish it in 2014, that's why I changed its name..
In 2015 I was in doubt what the definitive name should be.
The ZX-81 came out in 1981, so the 2015 version could be called ZX-15
But a ZX15 is a jamaha motorcycle, and there is no obvious connection to a ZX81 except the "ZX"
So an alternative name could be ZX-81 plus something extra, Its 34 years after the ZX-81, so ZX81+34 seems an okay name, although its a bit long and perhaps not as "catchy".
I ran a poll, and the outcome made me decide to go with ZX81+34.
This is a 3D rendered preview of it:
note that unlike a real ZX-81 the main PCB is not mounted upside down, but in the same orientation as the keyboard, and all connectors are in the back instead of the left side (because unlike the real ZX-81 main board the board is square not rectangular, and has pinheaders instead of an edge connector, on the left side, where it can accommodate expansion boards).
its latest schematic can be found at its current "home", which is the site of "RevSpace", a hacker/makerspace near where I live.:
(now updated 1 november 2015)
As the Revspace wiki is private, there was no public comment section there, (only for revspace members) so I made this thread instead.
more information, background story, schematics, keyboard layout and schematic etc etc, can be found on the Revspace site, in the "projects" section, https://revspace.nl/Main_Page