[time-nuts] Re: Crazy Clock

[David G. McGaw]

1PPS into a toggle flip-flop such as a 74AC74 w/ feedback (AC has strong 
output drive, can run off 2V to 5.5V) followed by a differentiator 
(could be just an appropriate capacitor) could generate the bipolar 
pulses for a standard battery clock movement.

David N1HAC

On 12/15/22 2:59 AM, Bill Beam via time-nuts wrote:
> Relatively easy DIY project.  Most battery operated wall clock movements are driven
> by a two phase motor - positive pulse followed by negative pulse.  Many GPS modules
> provide a single phase pps output.  The problem is to generate the bi phase from the
> single phase pps.  I have a Brooks Shere system running that has a 'heart beat' signal
> available (one second on, one second off).  If that signal is applied thru a series capacitor
> (about 47-100 microF) it will be differentiated to provide the bi phase pulses.
> Remove the battery from the clock.  Locate the motor winding and apply the bi phase signal.
> I have had a couple of wall clocks driven by GPS for years.  It only missis a beat if the GPS goes down.
>
> Alternate solution is to use a micro processor on a chip (about $2.50) to generate bi phase
> from pps.  That takes about 4-6 lines of program, depending on the chip.
>
> Regards.
> Bill, NL7F
>
> On Tue, 13 Dec 2022 15:09:26 -0500, Bob Camp via time-nuts wrote:
>
>> Hi
>> I realize that this is a bit of an odd project, but this is Time Nuts G??..
>> 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, IG??m lazy, I donG??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, IG??m looking for a mechanical gizmo with hands that move.
>> If it reads out 12 hour time thatG??s ok. 24 hour time would be super cool, but
>> itG??s not vital.
>> Anybody know of a source?
>> Thanks!
>> Bob
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>
> Bill Beam
> NL7F
>
>
>
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