Computer-generated dream world: Virtual reality for a 286 processor
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I'm not a fan of breadboards, they tend to be unreliable even for trivial circuits. We need something more affordable and practical for home PCBs[^1]. Why is it that nobody has invented a tin 3D printer, or at least a 2D version of it, i.e. a tin plotter?
[^1]: I'm discouraged from home-etching by the chemicals and the dark-room part of the process.
Since fabricating new boards took time and was expensive, a lot of work was done to make in situ modifications that involved an insane amount of wirewrapping. One member of the team did that all day, every day as their full time job, and I was always amazed by their ability to focus consistently at that level for so long.
How do you attach the components to it?
I remember reading some "Sputnik" magazines from the 1970s where Russian scientists were searching for the holy grail of a good conductor resin. I didn't understand at the time why they found the (concept of the) thing so valuable; but now I've got an inkling...
For attachment, I'd evaluate their conductive epoxy or maybe glue down the underside of the component and then smother the lead with the silver conductive ink. But again, just hypothetical since I have a quickturn shop make cheap prototype PCBs for me and either hand solder or use a stencil, paste, and a hot air gun for my hobbyist projects.
It was expensive and performed terribly.
I think there really isn't any good way to improve on breadboards. Breadboards, in fact, are the improvement. They're called breadboards because we used to literally drill pieces of wood and do wire-wrap construction on the other side.
Breadboards are good enough for the kind of prototyping they're for. Spring loaded contacts are about the best you can get for removable parts. The signal integrity isn't that bad at modest speeds.
In today's world, the next step up from a breadboard is custom PCBs. You can have a set of five shipped from China for the same price as a set of breadboards. There's no real need or reason for anything in between so long as PCB manufacturing is so disgustingly cheap and fast.
Both essentially built a DIY chip tester for a 286 and both built around a Harris 80C286.
If I understood it correctly, the goal behind this project seems simulating the rest of the PC, purely for the challenge and learning experience, documenting the process of building the chip tester (and getting mildly philosophical in the process).
The other project was more directly interested in the 286 itself, undocumented instructions, corner cases in segmentation behavior, instruction cycle timing, etc. and also trying to find out if there are any difference between the Harris and Intel variants.
[1] https://forum.vcfed.org/index.php?threads/286-cpu-experiment...
Love it. No notes.
Instead of futzing with wires on a breadboard you could simply designing a PCB up front, throw the design over the fence at JLC or PCBWay, insert coin, wait patiently at the mailbox, solder your scavenged Socket 7 onto the board.
The days of toner transfer and aquarium pumps are already long gone. Getting production quality, one-off, multi layer PCBs done as a hobbyist is dirt cheap these days, no government budgets required.
It blows my mind that I can use free-as-in-beer Free-as-in-Speech software to design a PCB, email it to a dude in China, and get a finished working professional-looking PCB back in my hand within a week, for the price of a couple of coffees. And if I want the components stuck on too, it'll cost a little extra, maybe three coffees it costs now.
If I want it really quickly then for the price of a decent takeaway curry I can have it flown over next day. What the actual hell?
Edit: the slowest part of "next day" is when it hits the UK, and if I could guarantee it just gets delivered to DHL's Edinburgh depot I could drive down there in two hours.
Electronics cost a lot to manufacture in the 70s, but is entirely automated now but for "reasons" we have only seen a small part of that savings.
When you buy the "Cheap" version on AliExpress, they are still making a healthy margin, yet Americans will happily buy the exact same product off Amazon for next day shipping for 10x the cost and think they are getting a "deal"
This extends to cars as well, with the F150 costing as little as $20k to build, even with "Expensive" very unionized and well compensated labor. The higher market trims only cost a little more to make but take in far higher profit margins. How much of China's supposedly "Subsidized" car price (as if the US doesn't do anything to subsidize cars) is just a lower profit margin?
Things should be way cheaper to western consumers. Where does all that extra money go? "Marketing and administration", basically bloated executive suites, bloated middle management, and the pockets of Meta, Google, AWS, and Apple. Oh gee, those exact companies seem absurdly wealthy and are basically responsible for all economic growth in the past few decades.
It's ludicrously expensive to ship things to and from the US though, and since they're now paying some insane markup because no-one understands what tariffs are the prices have got even sillier.
https://hackaday.com/2015/11/24/building-the-infinite-matrix...
That was the configuration I had when I went to college. I had an amber monitor that had a really crisp image and 5.25" HD floppy drives. The AT case was fantastic, I wish I had one today.