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Comment by daniel-cussen | Hacker News Reader

There is now a 17cm3 atomic clock chip on the market for about $2300, well under the price of a high-end watch. I'm surprised nobody's made a wristwatch with that.

The chip: CSAC SA.45s.

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Datasheet here:

http://www.chronos.co.uk/files/pdfs/sym/sa.45s.pdf

120mW, 3.3V? Totally doable as a wristwatch.

  120mW, 3.3V? Totally doable as a wristwatch.

I guess this is sarcasm? Typical quartz wristwatch power consumption is closer to .01mW.

You could do it with a rechargeable battery, like a smartwatch, though you'd be recharging it every night, like your phone.

Perhaps I should've said "wristwatch formfactor", you're right, battery performance would not approach cheap digital watch, not by a long shot. But at at 120mW, you'd be able to get a few hours out of it with a CR2032 cell, which is better than useless. Garmin made GPS wrist units that up until recently have done no better than this, although admittedly, there's probably more utility in having a GPS on your wrist than an atomic clock.

Your could write "HOURS AND HOURS OF BATTERY LIFE!!" on the packaging.

Yeah, but lithium coin cells are $5 each when your end user buys them at the grocery store.

Good point, that totally kills the economics of this project.

They have. http://www.ablogtowatch.com/bathys-hawaii-cesium-133-atomic-...

Because a >>$2300 wristwatch is a piece of jewelry, not a way to tell accurate-to-the-second time. Typically, it will have an intricate mechanical movement and be almost as accurate as a $5 quartz-driven electronic watch from the gift shop.

At that price point it's all about being unique. A quartz watch isn't unique - but a watch based on a $2300 atomic-clock-on-a-chip sure would be.

Absolutely. See Slyde watches: https://www.slyde.ch/ $5k+ for a watch with an LCD screen you can update via software. I appreciate they use high materials in the construction, but the profit margin on these must be huge.

Given that they're advertising military applications, I wouldn't be surprised if there are export regulations on such components.

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