I grew up in a world where the Arduino already existed, but it was not until I tried building homebrew Z80 computers like this that I really felt I understood how computers/processors work at the low level.
Consider this a warning though: this hobby has caused me to involuntarily collect every model of Z80 powered TRS-80 computer.
If you wish to become hooked anyway, this project might be another good place to start: https://hackaday.io/project/159973-z80-mbc2-a-4-ics-homebrew...
Here's some context on the RCA 1802 (COSMAC) Membership Card, also by Lee Hart at the same website, which is the real star of the lineup:
Love the Freak Brothers references; two US counter cultures that do cross pollinate. Z80MC RAM & ROM seem v generous compared to the ZX81 I used to cut my asm teeth, wobbly RAM pack and all...
Looks like the caption to the image references a "Creative Computing" cover from 1979—so an indirect FFFBrothers reference.
There's also an 1802 Membership Card—which I knew as the COSMAC Elf Membership Card [1][2]. Switches and LEDs. I built one of these kits a decade ago but mine didn't work. (I still need to pull it out and try to debug it. For all I know I did assemble it correctly and there is just a RUN switch or something I did not know to flip.)
Nice to see old tech revitalised - I had fun with the Australian version of a Z80 single board computer - https://en.wikipedia.org/wiki/TEC-1
It's a shame Zilog stopped making Z80s. Presumably this means you can't make one of these from new components any more. Perhaps someone could create a new iteration of the same idea.
The Z80 instruction set lives on via the eZ80, Z180 and others which are binary compatible with the original Z80 instruction set. Unfortunately Zilog stopped making the 40 pin DIP package a couple years ago so yeah this specific board will be hard to source. You can still find them on gray market, mostly ones that have been desoldered from existing boards.
Even if you made a version of this board with the footprint changed to the QFP eZ80, it probably wouldn't work because the eZ80 has different memory mapping and clocking differences.
The Z180 has however had its PLCC packages discontinued. Personally, I find SMD CPUs to not be appealing for these sorts of projects, even if the Z180 is a great chip.
Luckily so many were made, they will be around for a while yet. For years now you've been able to buy (recycled?) ones on Ebay or Aliexpress, and at a price much cheaper than the new ones sold for.
It will probably be a decade or longer until those sources start to dry up, but even at that the Z80 will never become as rare as say, a SID chip.
You can probably put together something similar with A-Z80 [0] or a similar FPGA redesign.
The Z80 is still used in consumer products. TI-80/TI-83 calculators are a well known example.
For the aspiring hacker, we've also got:
The 80's/90's VeriFone Tranz 330 credit card terminal, which has a complete Z80 computer inside with DART, CTC and PIO chips, 32K RAM, and a socketed EPROM.
The Cidco Mailstation, which has a Z80, sizable monochrome LCD, and full-ish size keyboard, perfect to hack into a TRS-80 Model 100 style laptop.
You can pick up either on Ebay right now for ~$25
Very cool. My version of this years back was a TI-83+ I learned asm on.
This is pretty eye-opening. It really drives home how simple the core control logic can be. Starting with toy cars or small-scale vehicles feels like a great way to teach and validate these ideas before layering on unnecessary complexity.
fwiw, I have two Z80s--maybe more--in a box among all my other parts.
I think this is very cool, even though I have no historical connection to the Z80 it's of course a well-regarded and firmly entrenched/popular retro CPU.
But this really is a stretch:
The Z80 Membership Card itself is a stand-alone single-board computer that can "power up" your projects, like the Parallax BASIC Stamps or Arduino microcomputers.
Both of those are very commonly called microcontrollers, not microcomputers, since they have all of those extra chips merged into the single package of the CPU.
Take a look at the Arduino Uno [1] which is a very typical (if old) example: you will see that the board is not covered in ICs from edge to edge, since all of the main functionality is in the single-chip microcontroller. I think the second big-ish package visible is for the USB, but that also disappears on more modern controllers with on-board support for USB.
[1]: https://en.wikipedia.org/wiki/Arduino_Uno#/media/File:Arduin...
I have very sadly done the same with ZX Spectrums but the quest is never ending due to all of the baltic clones
I went through the exact same process, but with the 6502 (Ben Eater's videos, and then another SBC of my own design after). It's helped me become a better programmer too. Example: pointers in C now feel very natural instead of some abstract idea of "memory addresses, whatever those are".
And yep, I now also own many 6502 based computers :-)