A thread to share and discuss fun computer electronics hardware projects, kits, experiments, etc which aren’t bog-standard PC builds.
I yearn for some modern-ish incarnation of a heathkit-/radioshack-style construct-your-own-computer kit. I’ve spent many hours ogling photos and video of SGI computers, inside and out. I romanticize the midplanes and backplanes and gloriously modular big iron hardware of yore, probably only because I didn’t have to live with it in the “bad old days.”
Here are some examples of the flavor I crave. Would love for people to bring other products/projects/designs to my attention. Hopefully you can tolerate my irrational longing for some impractical computer hardware I have no real need for. Would really like a plausibly useful level of performance, perhaps RISC-V or POWER, but my interests are broad.
Pretty spot-on in-concept Z80 backplane PC kit, but Z80 is so old and slow.
ditto Z180
Pine64 cluster board - neat, contemporary performance, but a bit less interesting than I’d like. Maybe if I had a specific actual use for cluster/distributed computing this could be a good solution.
Not quite what I thought I wanted until I saw it, but the ClockWork DevTerm lights up a similar part of my brain
The PiDP-11 Wendell showed off (also PiDP-8) is really cool and scratches the electronics assembly itch to an extent, but the fact the compute is just a raspi makes it less attractive, though the blinkenlights add some allure back.
Maybe I need to actually create something novel with one of my RasPis to try to scratch the hardware itch before I go buying more stuff.
I’ve been incredibly interested in this kind of homebrew kit computer stuff for a while too. Though, I’m perfectly happy with Z80/6502 tier (or less!).
It’ll be pretty difficult to find anything generally available even aproaching “modern” performance without going full MAGIC-1 http://www.magic-1.org/
Z80 and 6502 projects are your best bet for starting out, loads of documentation and still available new. Unfortunately, 68K and early PPC have been relegated to the computing dustbin in terms of availability and community surrounding homebrew projects.
I have a couple of ideas for building my own homebrew computer, one slightly simpler than the other
One involves creating a CPU simulator/Bytecode interpreter on an arduino with a screen and keyboard attached (has to be interpreted since atmel chips can’t execute code from ram. Harvard Architecture grumble grumble…). Basically what Java was supposed to be. Maybe could use one of those RISCV ESP32s with wifi. Free early Devember idea
The other is a fully custom CPU of my own design. Thinking of doing it out of discrete transistors on home-etched boards. I’ve got an instruction set drafted, just need to do block diagram and logic-level schematic.
Will be a massive project but a great learning experience.
Did you know you can get a box of 2000 transistors for only about $200? Aimimg for a filing cabinet sized “minicomputer” with blinkenlights.
Hint: FPGA. Emulate (almost?) any CPU arch, including its supporting chips, essentially as a text file. (OK, ok, not quite, but you get the drift ) Downside: an FPGA dev-kit that can handle any CPU arch is well north of $200
I’ve been designing the circuits using a digital circuit simulator called “Logisim”. Can be a bit slow at times but I’m used to it and it works. Also been testing logic gate combinations using real transistors.
I have used an FPGA before to design a CPU at University, they’re pretty cool but it’s still a big task to translate the VHDL to real hardware. Nothing beats circuit boards, toggle switches and blinkenlights!
Glad to know I’m not the only one who feels the urge to mess with stuff like this. Thanks for sharing your ideas and for the mention of Magic-1. I will enjoy reading about it.
Sounds like your ambition is a bit greater than mine. I happened across this MangoPi RISC-V board that might could make for a good starting point “heart” for a little extensible computer…
Or perhaps better would be this Sipeed Risc-V board with Allwinner D1, 512MB ram, and a breakout board.
For over $100 they have more of a RasPi form factor
I guess these are all based on the same 1GHz singlecore RISC-V 64bit SOC. Maybe too high-level for your tastes, but this is tempting me.
It’s cool to imagine if they die shrunk something like the z80 to like 28nm, how many could they fit on a wafer, how much power would it suck up, how fast could you crank it
) Downside: an FPGA dev-kit that can handle any CPU arch is well north of $200 