The Whizz80 computer project is an open-source, home brew, retro computer based on the old 8-bit Z80 CPU by Zilog from the late 1970s. The goal is to have a working stand alone computer, both hardware and software using easily available components and materials that anyone could build.
It is a computer built from scratch running a Forth like operating system. The goal is to have a complete stand alone computer (with it's own input/output devices, not relying on a tether This project is in it's early days, there isn't much to show as of yet. m another computer like a serial connection).
This is quite an ambitious project, and I suspect it will take some time to do.