Homemade Clackulator

Craft & Design
Homemade Clackulator


When you think “pocket calculator,” your next thought probably isn’t “custom cabinetry.” But for Simon Winder in Seattle, his single-operation relay calculating engine, built over five years, with over eight months of full-time work, deserved nothing less. The cabinet was built by local artisan Matthew Richter.

“You can easily see how these devices [electromechanical relays] are being used, in contrast to modern computers where the operations happen far removed from human senses,” muses Winder.

M39-clackulator-Simon-WinderThe machine has one function: to calculate and display a square root. The user enters a number on a rotary dial, whose pulses are stored in binary by the system of relays. The start button activates a mechanical clock pulse generator that triggers every operation state with precision timing.

A full calculation takes about a minute. While the operations cascade through 480 relay switches, hand-wired into circuits, each closing relay declares itself by lighting up with a satisfying mechanical clack. A bell announces completion of the final calculation, and the answer displays on eight nixie tubes.

Winder will be bringing his fantastic contraption to Maker Faire Bay Area 2014.

For more, visit simonwinder.com/projects/relay-calculating-engine.

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Gregory Hayes is a helpful being who has lots of fun. He makes most of his living as a photographer and writer, and occasionally tweets @mootpointblank.

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