> Here is another idea: how about subjecting the watch to 32KHz ultrasonic
> sound that beats with, and pulls the tuning fork?
I did this a couple of years ago with mixed results. I think
one reason is that the hp 32 kHz signal generator wasn't
stable enough and I probably dithered the poor tuni
In a message dated 12/2/2007 05:58:05 Pacific Standard Time,
[EMAIL PROTECTED] writes:
>And reading the watch face might be one of those minor
>details that kills the project.
>-Chuck Harris
Hi Chris,
thanks :)
This sounds like a fun two-member senior project..
Here is another ide
Hi Said,
It never ceases to amaze me what a creative mind
can come up with!
Be sure that you keep the temperature extremes down to
something that would be comfortable to your skin.
And reading the watch face might be one of those minor
details that kills the project.
-Chuck Harris
[EMAIL PROTE
Saturday, December 01, 2007 8:44 AM
Subject: Re: [time-nuts] Chronometer contest sponsored by IEEE Spectrum
> Hi Max,
>
> I haven't seen a quartz watch with a trimmer capacitor
> in something like 20 years.
>
> What they do now days is use a microprocessor with flash ra
Hal Murray wrote:
>> The thing is watches rates are dependent on how you personally wear
>> them. Some people's wrists are warmer than others, some people take
>> the watch off at certain times of day, others don't... If you wear
>> the watch normally, and measure your personal offset, you can adj
In a message dated 12/1/2007 07:23:05 Pacific Standard Time,
[EMAIL PROTECTED] writes:
>Twiddling the trimmer on those watches that do have one (really old watches)
>is not the right way to do the job. You will waste an incredible amount of
time
>moving the trimmer, and waiting only to fin
> The thing is watches rates are dependent on how you personally wear
> them. Some people's wrists are warmer than others, some people take
> the watch off at certain times of day, others don't... If you wear
> the watch normally, and measure your personal offset, you can adjust
> the crystal to
Twiddling the trimmer on those watches that do have one (really old watches)
is not the right way to do the job. You will waste an incredible amount of time
moving the trimmer, and waiting only to find that you overshot your mark. Here
is the correct way to do it:
Before you test, set the watch
Hi Max,
I haven't seen a quartz watch with a trimmer capacitor
in something like 20 years.
What they do now days is use a microprocessor with flash ram, and
the timing machine reprograms the microprocessor's second counter
to trip at the right time.
-Chuck Harris (amateur watchmaker)
Max Robins
-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of Max Robinson
Sent: Saturday, December 01, 2007 1:09 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Chronometer contest sponsored by IEEE Spectrum
In my experience watches come from the factory a
I found this article randomly this evening, it has some interesting
tidbits about quartz oscillators in watches. I had never heard of the
venerable Sieko "twin quartz" from 1978, good to +/- 5 seconds a year:
http://people.timezone.com/msandler/Articles/CarlosFinalParadigm/FinalParadigm.html
Max Robinson wrote:
> In my experience watches come from the factory adjusted to gain about 5
> seconds a month. The ones I have owned over the years seemed to be fairly
> stable in that. I have always wished there was a way for someone who is not
> a watch maker to open up such a watch and tu
To subscribe to the fun with tubes group send an email to,
[EMAIL PROTECTED]
- Original Message -
From: "Hal Murray" <[EMAIL PROTECTED]>
To: "Discussion of precise time and frequency measurement"
Sent: Friday, November 30, 2007 12:04 PM
Subject: Re: [time
On Nov 30, 2007 1:04 PM, Hal Murray <[EMAIL PROTECTED]> wrote:
>
> > With a little work you might be able to precisely calculate the
> > maxima of the parabola and precisely set the frequency independent of
> > temp and aging. Ha!
>
> What's the aging like for watch crystals?
>From a 32.768 kHz
> With a little work you might be able to precisely calculate the
> maxima of the parabola and precisely set the frequency independent of
> temp and aging. Ha!
What's the aging like for watch crystals?
What type of cut to watch crystals use? Are there any generalizations about
aging?
I don
> Are surplus parts such as Ebay OCXOs OK? (That's an 'open market' to me!)
I got eight 3 MHz OXCOs for $32. They don't have electric tuning, but the
one I played with seems pretty stable. It takes a significant dip if I grab
the can with my fingers but there isn't any obvious 24 hour pattern.
>> I think that I would start by looking at 32kHz watch crystals, I've
>> often wondered how good a timebase you can make out of one. The tempco
>> is a parabola around 25C with a max slope of something like 0.05 PPM/C,
>> so they are naturally a pretty good timebase with good aging
>> charac
Jeff Mock wrote:
> Jeffrey Pawlan wrote:
>
>> On Thu, 29 Nov 2007, David Forbes wrote:
>>
>>> It might be more fun to require that an OCXO be designed and built by
>>> the DIY-er out of commercially available crystals and resistors. That
>>> way, it's an engineering challenge instead of a p
In message <[EMAIL PROTECTED]>, "M. Warner Losh" writes
:
>If it wasn't for the $100 price point, I have exactly this in my
>office right now: Our product displays the time on 7-segment LEDs.
>However, our cost is somewhat more than $100 since we have an OCXO,
>a TCXO, a GPS receiver, an ARM and a
David Forbes wrote:
> At 10:42 AM -0500 11/29/07, [EMAIL PROTECTED] wrote:
>> IEEE Spectrum, the magazine of the Institute of Electrical and Electronic
>> Engineers, is issuing a D-I-Y challenge that may be of interest to the
>> members of this group. The goal is to build the most accurate possible
Jeffrey Pawlan wrote:
>
> On Thu, 29 Nov 2007, David Forbes wrote:
>> It might be more fun to require that an OCXO be designed and built by
>> the DIY-er out of commercially available crystals and resistors. That
>> way, it's an engineering challenge instead of a procurement
>> challenge, since I
In message: <[EMAIL PROTECTED]>
Jeffrey Pawlan <[EMAIL PROTECTED]> writes:
:
:
: On Thu, 29 Nov 2007, David Forbes wrote:
: >
: > It might be more fun to require that an OCXO be designed and built by
: > the DIY-er out of commercially available crystals and resistors. That
: > way, it
On Thu, 29 Nov 2007, David Forbes wrote:
>
> It might be more fun to require that an OCXO be designed and built by
> the DIY-er out of commercially available crystals and resistors. That
> way, it's an engineering challenge instead of a procurement
> challenge, since IEEE is about engineering.
>
At 10:42 AM -0500 11/29/07, [EMAIL PROTECTED] wrote:
>IEEE Spectrum, the magazine of the Institute of Electrical and Electronic
>Engineers, is issuing a D-I-Y challenge that may be of interest to the
>members of this group. The goal is to build the most accurate possible
>digital clock for under $1
IEEE Spectrum, the magazine of the Institute of Electrical and Electronic
Engineers, is issuing a D-I-Y challenge that may be of interest to the
members of this group. The goal is to build the most accurate possible
digital clock for under $100, accuracy to be measured before disciplining
with
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