[time-nuts] Sidereal timekeeping

[Chuck Harris]

Hi Bob,

Certainly!  Silicon and programming is so cheap that you
can do wonderful things in tiny little spaces that takes
virtually no power to run.  A 12 pin PIC microprocessor
could easily add that level of control to such a clock
or watch motor driver.

I stopped looking at analog quartz wristwatches when they
were in the driving generation I described below.  I would
be shocked if there hadn't been an order of magnitude improvement
since then.

My personal preference is for highly jeweled totally mechanical
automatic winding  wristwatches.  My hobby compels me to have
high accuracy time and frequency around, but my life just
doesn't run with that kind of precision.

-Chuck Harris

Bob Camp wrote:
> Hi
>
> If you dig into the data sheets on modern watch driver IC's they get pretty crazy
> with the drive waveforms. They do a PWM / switcher like sequence on each drive
> pulse and look at the current in the coil. The objective is to just barely put in
> enough power to supply the torque required.
>
> Bob
>
>
> On May 19, 2011, at 7:35 AM, Chuck Harris wrote:
>
>> An actual quartz analog wristwatch wouldn't do something so mundane as to use a
>> 50uf capacitor to drive the coils.  They do this:
>>
>> DRIVER-A---------------------COIL-----+ ......................................|
>> DRIVER-B------------------------------+
>>
>>
>> And feed the drivers with these waveforms:
>>
>> 1.5V..........+-+.............+-+.............+-+......
>> ..............|.|.............|.|.............|.|...... A-------------+
>> +-------------+ +-------------+ +---...
>>
>> 1.5V..+-+.............+-+.............+-+..............
>> ......|.|.............|.|.............|.|.............. B-----+ +-------------+
>> +-------------+ +-----------...
>>
>> Where the pulses alternately come from A and B every second.
>>
>> If you use a PIC to drive the clock, the driver is easy to program in software.
>>
>> -Chuck Harris
>>
>> iovane at inwind.it wrote:
>>> I understand now why most analog wristwatches do tick every two seconds when
>>> the battery is low. I believed the logic used this trick to signal low
>>> battery.
>>>
>>> Antonio I8IOV
>>
>> _______________________________________________ time-nuts mailing list --
>> time-nuts at febo.com To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the
>> instructions there.
>
>
> _______________________________________________ time-nuts mailing list --
> time-nuts at febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the
> instructions there.
>