A blog about a computer made from relays

My journey in constructing an 8 bit relay computer from scratch ... made from of a ton of solder, wires, lights, relays, sweat, tears, swearing and money.

Welcome

This is my blog covering the design and construction of a computer made from relays. If you're new here then a good place to start is the overview page.

The summaries also give more detail on the various aspects of the computer: ALU, Control, Enclosure, Instructions, Registers, UI &

To see how far I've got check out the Progress page.

Latest Post:

2020 Update

As the clock struck midnight at the very end of 2019 I decided, over a glass of something sparkling, that I’d set myself a challenge to put out a series of six YouTube videos within...

Decoder Construction

In my last post I covered off the full design for the decoder card so all that remains is to get it soldered up and...

05 Jan 2020   —  1 minute read

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Decoder Design: Schematic & PCBs

I’ve almost got everything I need now to get my relay computer to do branching. The hard work of designing and constructing the sequencer and...

22 Dec 2019   —  4 minute read

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Controller Construction

In my last couple of posts I covered off the full design for the controller unit. As the PCBs have now arrived I can get...

21 Dec 2019   —  1 minute read

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Controller Design: Schematic & PCBs

In my last couple of posts I finalised the controller schematic designs for the ALU, SETAB, MOV8 and GOTO class of instructions. Now it’s time...

20 Dec 2019   —  4 minute read

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Controller Design: GOTO Instruction

With the sequencer now designed and constructed I’m much closer to getting branching working on my relay computer. The next hurdle is updating the controller...

30 Nov 2019   —  4 minute read

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Sequencer Construction

In my last couple of posts I covered off the full design for the sequencer unit. With PCBs now safely arrived in the post I...

20 Nov 2019   —  2 minute read

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Sequencer Design: Schematic & PCBs

I’ve got the designs for the 24-cycle FSM and pulse distribution in place so all that’s left for the sequencer is to bring the schematics...

11 Nov 2019   —  5 minute read

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Sequencer Design: 24-cycle FSM

Recently I’ve been looking at what’s needed to implement branching in my computer (the upcoming GOTO class of instructions). In my last post I covered...

01 Nov 2019   —  3 minute read

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Branching: Opcode Timing

In my last post I covered the design for the GOTO opcode which will enable my relay computer to perform branching, loops and so on....

06 Oct 2019   —  4 minute read

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