Make a computer from scratch kits?

Have you considered logic simulators? That might be a cheaper and easier way to play around until you have your design figured out.

Screw logic simulators. Wires, transistors, chips, and LEDs is what you want.

:slight_smile: That’s my feelings, too. I want to get my hands on the parts. But it’s a cool tool if I ever want to get something really complicated going and at least seeing if it works in theory. But I think that’s at a far more advanced level than I am now.

This little 4-bit transistor computer, while not from a ready-to-go kit, seems like it should be doable without too much fuss in getting the parts.

Screw transistors. Use relays. They go clickety-clack and are awesome.

(I’m actually in the middle of building a 8-bit relay adder on some old protoboard, using designs left over by Konrad Zuse. Here’s my one-bit prototype.

If I have enough relays leftover I’ll add in some sequential logic and make a real computer.

That thing looks really cool. I’m pretty sure I could launch a few nuclear missiles with it.

The first computer I ever did more than type a few terminal commands on was an Altair 8800 I helped a friend build. You can still find the kits (at least, the PC board set) out there.

I remember it was quite a thrill to toggle in the NIM game and have it work. :smiley:

That was a sweet machine- but the 8080A chip uses funny supply voltages.
+12, +5 and -5, I believe. The Z-80 and later were pure 5V devices, so simpler to build a working computer.

In EE 474 (IIRC) we designed and built (wire-wrap) an 8085 based computer. Basically it was a CPU, a UART, a RAM chip, and an EPROM.

The “OS” which we wrote had 4 commands - read some memory, write some memory, run a program, and something else (my partner and I wrote a Morse code sending program)

We interfaced with the serial port.

Good times.

Brian