[time-nuts] Most accurate clock on your wrist

David Forbes dforbes at dakotacom.net
Thu Apr 19 13:58:06 EDT 2007


Neon John wrote:
> I've been waiting with baited breath for a GPS watch.  NOT a NAVAID on
> the wrist but a simple GPS-synced watch.  It would seem to me that
> making a miniature GPS receiver would be much easier than making a
> WWVB receiver.
> 
> Unfortunately that watch ain't it.  Gad, they need a good industrial
> designer!  
> 
> Maybe they'll put the same electronics in a table/travel clock.  If it
> had a 1PPS connector on the back, so much the better :-)
> 
> John
> 

The Casio watch is rechargeable, since the GPS function drains the 
battery in two hours. Amusingly, it takes three hours to charge it, so 
the GPS drain current is higher than the charger's output!

Recharging a wristwatch is not my idea of a good time. It needs to be 
very easy to do. A USB-powered charger may be ideal.

I expect a practical GPS wrist-mounted timepiece would use the GPS only 
every couple of days to resync, giving time accurate to perhaps a few 
tenths of a second. You could always request a resync if you needed to 
know precisely what time it was.




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