

Homemade relay computer (6 Hz) - mhb
http://web.cecs.pdx.edu/~harry/Relay/

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ctkrohn
Wow. Not sure which is more hardcore -- this, or the guy who built a complete
programmable replica of the Apollo guidance computer using only the original
manuals: <http://klabs.org/history/build_agc/>

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mhb
I think he's using the computer to host his web site.

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treed
I read about this a month or two ago. Watched the video, read the whole paper,
it's awesome. A great way to demonstrate that computers are really just
machines and not magical at all.

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Tichy
How does it make money?

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Prrometheus
You invite people over to use it, and then you make them watch an ad first.

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boredguy8
Things like this make me wish (a little) that I had been an electrical
engineer rather than a CS major.

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dfranke
You could do this with a CS background, I think. Relays are very simple to
understand. If current is flowing from A to B, then current can flow from C to
D. Otherwise, it can flow from C to E. They way they work (conceptually; I've
never taken one apart) is that running current from A to B powers an
electromagnet. There's a wire tied to C and the other end is pressed against E
by a spring. The electromagnet pulls on the spring and moves the wire from E
to D. They're just little mechanical if-then-else constructs.

If you run a wire from B to C and connect a battery to A and E, you'll get a
nice buzzing sound as it oscillates between states.

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jedediah
Got to see a demo of this system in person, and it was truly spectacular. I
learned more in 10 minutes watching this thing than I did reading multiple
books. (I took 'Compilers' from this guy, HIGHLY recommended to anyone who
happens to be at portland state.)

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sammyo
Wow, just about perfect... sixth photo down, it seems to be in his bedroom.
And there is a Home build CPU 'ring',yow!

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albertcardona
I could use one of those to illustrate basic internals to my father.

