Go back to the future with this DIY arithmetic unit

Arith-Matic S1-AU Mk1

How does a computer work? That’s the question that Arith-Matic are aiming to answer. They’re launching a beautifully crafted 4-bit arithmetic unit built out of 7400 series logic chips. Four input switches allow you to load data into two registers, and display the result. This result can then be loaded back into one of the registers, allowing rudimentary multiplication. All the processing takes place in 7400 series chips (flip-flops, multiplexers, adders, logic gates, etc.) – there are no programmable parts on the board. Don’t be fooled by the USB cable – there’s no data uploading, it just provides power.

The board comes in kit form, so you will need to know how to solder it together, but that’s the only knowledge you need to use it. There’s a comprehensive manual available digitally which goes through how the board works – including descriptions of the various sub-elements that make the board work (de-bouncing circuits, current-limiting resistors, etc.), and how the processes demonstrated in the board fit into the larger picture of computing.

It could be a good tool to help children understand what goes on inside computers, but it is more than this. It’s the combination of form and function which particularly impresses us. The well-spaced through-hole components with large (5 mm) LEDs hark back to the older days of homebrew computing. They look great on a slate-grey PCB which is designed for its aesthetics as well as working really well. It’s the sort of circuit board that’s fun to assemble and play with, but also looks great adorning your workshop.

From £40 arith-matic.com Delivery: 2018

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