[time-nuts] GPSDO Alternatives

Don Latham djl at montana.com
Fri Dec 7 17:56:51 UTC 2012


but we could use a less expensive one. a simple light interruptor senses
the end of flow, a robust servo turns over the hourglass for the next
cycle. our favorite arduino counts seconds from the gps, and adjusts the
turnover appropriately. If magnetite sand is used, an external magnetic
field can provide rate correction for phase control rather than
frequency control?
A smaller version would generate the perfect 3 minute egg.
o gosh maybe this thread is petering out in my head
don L

Bob Camp
> Hi
>
> That is an impressive hourglass. In the context of the thought
> experiment "swap offer" - no, mine is not a work of art. It's only value
> is as a time keeper.
>
> Bob
>
> On Dec 6, 2012, at 10:37 PM, DaveH <info at blackmountainforge.com> wrote:
>
>> If you had an Ikepod, I might be interested.
>>
>> http://www.ablogtowatch.com/ikepod-hourglass-time-for-art/
>>
>> http://www.hodinkee.com/blog/2011/3/29/the-ikepod-hourglass-by-marc-newson-q
>> uite-possibly-the-coole.html
>>
>> http://www.ikepod.com/
>>
>> Dave
>>
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com
>>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Bob Camp
>>> Sent: Thursday, December 06, 2012 18:23
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] GPSDO Alternatives
>>>
>>> Hi
>>>
>>> Here's another way to look at this:
>>>
>>> An hourglass full of sand (with some attention) and a cesium
>>> standard are both ways to answer the question "what time is
>>> it?". Let's say you need a new $40,000 tube replacement in
>>> your 5371 and management asks "what else can we do?".  An
>>> hour glass  is indeed a "something else we can do". They both
>>> deliver an answer to the time of day question. Without
>>> defining what you actually *need* to do, they are both valid
>>> approaches.
>>>
>>> The problem comes when you look at the $40,000 repair charge
>>> and decide that building an hour glass is a lot cheaper.
>>> While that's true, it's far from the whole story. One way to
>>> quickly work some of this out is a simple swap proposition.
>>> Would anybody on the list trade their (working) cesium for my
>>> (working) hourglass? I'll pay shipping..
>>>
>>> Bob
>>>
>>> On Dec 6, 2012, at 9:03 PM, Mark Sims <holrum at hotmail.com> wrote:
>>>
>>>>
>>>> I think only TIMER2 on the AVR has the clk/4 limitation.
>>> The other timers can count at full speed.    I know that I
>>> have counted at 8-12 MHz before...
>>>>
>>>>
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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."
De Erroribus Medicorum, R. Bacon, 13th century.
"If you don't know what it is, don't poke it."
Ghost in the Shell


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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