That's a really good idea!!! (wish I'd thought of it)

It wouldn't be too hard to put in 'one-button time set' which would cycle
through the time zones.  Daylight savings time might be a bit more involved,
perhaps just let the user push the button to a different time zone each fall and
spring.

If you are marketing this in the US you can assume daylight savings time for all
but two states.  Set it on by default, and tell them they can toggle it on or
off by holding the time-set button down for 3 seconds.

The time zone and daylight savings time problem still remains with the WWV/WWVB
time broadcasts, and requires a similar solution.

The only difficulty is not whether the RTC lasts for 10 years, but whether it
has +/- 1 minute accuracy every ten years!  (ie, practically impossible, it can
be done, but not for cheap...)  I suppose if you design the liftime of the
product for 1-3 years you can probably get away with up to 2 minutes difference
after each year.

<humor>
PRODUCT NOTES: If your coffeemaker clock is running fast (ahead by 1 minute or
more) please place it in your freezer for 2 days.  Be sure to let it warm up to
room temperature before using it after it is removed from the freezer.  If your
coffeemaker clock is running slowly, please bake at 200 degrees Farenheit for 2
hours for each minute it is behind.  (caution: Product may be hot right out of
the oven!)
</humor>

Or even still, put the WWVB receiver in it with the RTC, and tell them to leave
it on their roof for a day if the time is wrong.  People will think your company
is crazy!

-Adam

"Giles L. Honeycutt" wrote:
>
> Well, do you need to do it?  Can a low power RTC work if it lasts
> for 10 years?  Set it on assembly of product.
> Just an idea, I don't know the constraints of the project.
>
> Best regards,
> Giles
>
> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Lance Allen
> Sent: Sunday, February 13, 2000 2:27 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: Internet Toaster
>
> >
> > I'm asked to incorporate some kind of module that communicates with an
> > external time standard (WWV, GPS, atomic time, whatever) that programs the
> > clock on appliances  (coffeemakers especially.)  You plug it in, it knows
> > what time it is.  Simple.
> >
> >
> > Not for me.  Anybody heard of these little modules?
> >
> > -- Lawrence Lile
>
> I think that the only practical way with present technology is to
> have a through-the-AC-mains comms that each appliance listens to
> with a master unit that publishes the time.
> The master unit can either be a GPS, Radio time receiver or
> whatever.
> So each house/facility has one of these master units and the
> appliances that need to know the time have cheap little decode
> units in them. That way you can control cross coupling of the
> superimposed HF in household mains circuits relatively easily,
> often not needing any coupling at all.
> You could even consider the dreaded X10.
>
> _____________________________
>
> Lance Allen
> Technical Officer
> Uni of Auckland
> Psych Dept
> New Zealand
>
> www.psych.auckland.ac.nz
>
> _____________________________