[time-nuts] Re: Crazy Clock

[Bob Camp]

Hi

Indeed, one could simply set any convenient clock to the “wrong time” and then
feed it a pps signal from any of a large number of possible sources. Been there /
done that. Lots of pps sources and lots of setups. It does indeed work.

Around here, it works (with the right offset) for a month or three. Somewhere along
the way something (there’s a long list …..) happens. If the something is major you
probably notice the issue. If the problem is minor …. it may go uncorrected for a
while. A one second jump is not all that easy to spot. Once I loose the correct offset, 
I loose the functionality that I’m after ….

My WWVB wall clocks go out when the battery dies. I replace the battery and 
pretty soon, they displays the right time. I can worry about other things and not about 
the clocks. I’d like the same sort of functionality in a clock that displays GPS System
Time. If it’s running, it has the right data to a “good enough” level of precision. 

So what is GPS System time that’s good enough? 

It needs to have the correct number of seconds offset from UTC. If that’s 18 today 
and becomes 19 next June, ideally it should handle that without operator intervention.

It needs to hit midnight at the right time of day. No daylight savings / summer time 
changes. If the GPS system thinks it’s midnight, that’s what the clock should say. 

Both of those things ( in the ideal case ) would set up from a cold boot all by
themselves. No operator intervention. The clock in this room comes up and so
does the one in that room and the one down over there. 

So yes, this is crazy. It’s not rational. It’s more than a bit insane. 

Sorry about that !!

Bob

> On Dec 15, 2022, at 8:08 PM, Louis Taber <ltaber at gmail.com> wrote:
> 
> This might be shy of what you are after, but it is a thought I have had for years now.
> 
> A GPS module with a pulse stretching circuit connected to an electromagnet near the pendulum on a grandfather clock.  
> 
> You would still need to set and wind the clock, but it seems that it would stay synchronized to the GPS signal.
> 
>   - Louis
> 
> On Wed, Dec 14, 2022 at 10:09 PM Bob Camp via time-nuts <time-nuts at lists.febo.com <mailto:time-nuts at lists.febo.com>> wrote:
>> Hi
>> 
>> I realize that this is a bit of an odd project, but this is Time Nuts …..
>> 
>> I want a analog wall clock that reads out GPS time. As far as I can tell, nobody
>> is crazy enough to make one and sell it in the open market. If indeed there is
>> one out there, that would be great. This does not have to be a project.
>> 
>> If it is a project, I’m lazy, I don’t want to set the thing and then count on it never 
>> missing a beat. I want a movement that has some form of feedback. The 
>> WWVB clocks have a movement like this. I could tear one apart and try to 
>> reverse engineer the guts. That sounds like. a project inside a project.
>> 
>> Does anybody sell feedback movements like this in the hobby market? If so has 
>> anybody used one and can vouch for it working for more than a few months? 
>> 
>> Indeed, doing it with a display of some sort would be easier in some respects.
>> For now at least, I’m looking for a mechanical gizmo with hands that move. 
>> If it reads out 12 hour time that’s ok. 24 hour time would be super cool, but
>> it’s not vital. 
>> 
>> Anybody know of a source?
>> 
>> Thanks!
>> 
>> Bob
>> 
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