Sinclair's wrist calculator: would you wear it now?


This extravagant wristwatch is an early product designed by Sir Clive Sinclair, who went on to make the successful ZX series of ultra-miniaturized home computers. It was, by all reports, a surprise hit.

8 digits, red LED. ... Launched in February 1977. ... Was available only as a self-assembly kit, by mail order from Science of Cambridge, previously Sinclair Instrument Ltd., which had been founded by Clive Sinclair and to which he moved from Sinclair Radionics. ... Total price was only £11 Sterling (about US$20).

Now a staple of weird wristwatch lists, there remains a certain combination of technical amazement (in its native 1977, it was crazy small) and untrammeled nerdliness that infuses this particular model with an eternal charm. It does not, of course, actually tell you the time.

Sinclair Wrist Calculator [Vintage Calculators]
Sinclair watch will make a geek grin [Make]

Published by Rob Beschizza

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  1. It’s interesting to see the multi-use keys that were so integral to the ZX81 in an earlier incarnation!

  2. Would I wear it today? You damn right I would, if only to get people to ask me questions about it!

    That is one cool gadget, boy, and no mistake. I always thought the Sinclair DIY ethic was cool, and my first computer was a Timex-Sinclair 1000. A good friend at that time was a Sinclair fan and bought their scientific programmable calculator kit… it was this stylish, neat little thing that had a *violet* display.

    It looked pleasantly geeky, not too-stylish geeky like the HP-01 (which I never could have afforded).

  3. I actually bought one of these kits in 1977. It was a little bit like those FULL SIZE SUBMARINE ads in the back of comic books… it looked snazzy on paper, but the reality wasn’t quite as wonderful. It was unbelievably cheap and flimsy, and worked for about a day before it crapped out for good.

    One more thing… it was just a calculator, not a wristwatch. There were no clock functions whatsoever. That lessened its appeal considerably.

  4. I wonder what was with the design choice of the right-to-left, bottom-to-top key placement… I guess bottom-to-top is standard on calcs but right-to-left?

    And how were the function keys activated? And what’s with the miniUSB port on the side? So many questions…

    I love it, I want one.

  5. It was unbelievably cheap and flimsy, and worked for about a day before it crapped out for good

    But just imagine… wearing one of these, with x-ray glasses on, tooling around on your homemade vacuum cleaner hovercraft with a spy camera and a bowl of Sea Monkeys… man, you’d rule the neighborhood.

  6. I realize no one will probably actually ever read this, it being now nearly a week since this was posted, but…

    Futrell, I had the same question about function keys. So, I clicked through here to see if anyone answered. They didn’t, so I looked again, and puzzled.

    If you look carefully, you may note a few things. Every key except the zero has two symbols – one in the upper left, one in the upper right. The 4’s left symbol appears to be a dot (which could be multiplication), but 5’s left symbol is an “x” (which certainly is multiplication). Then, I guess, that the upper right function of a key is accessed by chording with 0, and the upper left function is accessed by chording with 4. For example, to do the operation “103 x 59”, you’d do 1, 0, 3, 4+5, 5, 9, 0+4.

    Of course, I never owned one, maybe it’s more harebrained than this. But, that’s how it looks to me like it works.

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