[time-nuts] Regulating a pendulum clock

Don Latham djl at montana.com
Sun Aug 8 23:02:04 UTC 2010


fast blow fuse, resonate the coil to the pwm frequency. Parts count small,
tinkering in software instead of breathing lead fumes or whatever noxious
stuff the Europeans have forced us to use...
Don

Bruce Griffiths
> No protection against external shorts or other undesired events.
> Extensive analog filtering to avoid creating an effective radiator of
> noise may also be necessary.
> Simple analog techniques are probably simpler/cheaper once the necessary
> filtering and protection are included.
>
> Bruce
>
> Don Latham wrote:
>> Hmmm lemme see. I think I'd use a 12 volt supply and two transistors
>> driven by two outputs on my Arduino,basic stamp,picaxe or other whizzie.
>> I'd then implement a PID controller essentially using the 1 sec pulse
>> from
>> the pendulum and the 1 sec pulse from my Rb, satellite receiver, crystal
>> clock, or whatever. The appropriate output pin will be brought to
>> ground,
>> and the other driven as a pdf with the rate given by the pid loop.
>> Temperature and even pressure corrections can be applied within the
>> gizzie
>> software. External parts, minimum. Opportunity to play with tuning,
>> maximum.
>> Don
>>
>> Bruce Griffiths
>>
>>> J. Forster wrote:
>>>
>>>> You are picking very unimportant nits.
>>>>
>>>> If there were a small noise spike from the opamp, it'd goose the
>>>> pendulum
>>>> a tiny amount. That would be corrected on the next swing.
>>>>
>>>>
>>> Heuristic analysis of this type is counter productive.
>>>
>>>
>>>> You are turning a trip to the corner store into an Apollo Moon
>>>> Mission.
>>>>
>>>>
>>> Reliability is paramount in a circuit that may be required to work for
>>> decades.
>>>
>>>
>>>> BTW, since the =drive does not to be bipolar, one of the NPN and PNP
>>>> transistors can be deleted. They never turn on. So you are left with
>>>> two
>>>> opamsa, =each with a simple emitter follower.
>>>>
>>>>
>>> The original request was for a bipolar drive.
>>> The lack of short circuit protection is poor design practice when
>>> driving an external load.
>>>
>>>
>>>> -John
>>>>
>>>> ==============
>>>>
>>>>
>>> Bruce
>>>
>>>
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>>
>>
>
>
>
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-- 
"Neither the voice of authority nor the weight of reason and argument are
as significant as experiment, for thence comes quiet to the mind."
R. Bacon


Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com




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