[time-nuts] Re: Crazy Clock

[Lux, Jim]

On 12/15/22 9:57 AM, Alexander Huemer via time-nuts wrote:
> As pointed out by other people already, there are several analog wall
> clocks out there that can be set by external means like NTP, GPS, etc.
> In my mind they all suffer from the same flaw, which is their
> functionality is restricted to advancing time in precise increments but
> don't "know the time". I.e. if power goes away and comes back, you'll
> have to set such clocks by hand, even though their motor function can be
> influenced. What is lacking is a set of 3 absolute position rotary
> encoders with 6° resolution like described at [1] which referenced [2].
> Somebody^{TM} should put such a clock together. 3 such encoders, a
> stepper motor with gears to arrive at 6°, the rest is just software.
>
> -Alex OE2AHL


There are clocks that pulse forward with one polarity, and reset to "top 
of the hour or day" with a negative pulse.  My middle school had them in 
the 1970s, and it was interesting to watch the reset cycle (at noon).  
Or, to be honest, it might be some sort of "power switching" protocol. 
That is, use 60 Hz to run, but some pattern of interruption sets it to a 
known time.  But I remember watching the minute hand snap to 12, then 
advance in discrete steps.