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
Analog quartz clocks may be used as slave clocks.
You do not even have to disconnect the quartz movement.
Just find the coil
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:
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.
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
I am quite aware of the fact that quartz clocks and watches drive
their movements directly from their supplies with tailored pulses.
What I said was that a 0.5 Hz square-wave from a logic source
will drive these movements if you select appropriate values of
series capacitor and resistor.
Not
Michael wrote:
You are right, the right value for the crystal would be about 32859.27, but
I
thought that such a difference could be compensated in the circuitry,
that's
why I omitted the decimals.
before you get into grinding I have a question on your chosen frequency.
It doesn't square
On 5/18/11 2:18 AM, iov...@inwind.it wrote:
Michael wrote:
You are right, the right value for the crystal would be about 32859.27, but
I
thought that such a difference could be compensated in the circuitry,
that's
why I omitted the decimals.
before you get into grinding I have a question
...@febo.com] On
Behalf Of Bob Camp
Sent: Wednesday, May 18, 2011 8:09 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Sidereal timekeeping
Hi
The question can be easily worked out. A PIC running a 32,768 Hz clock will
pull X ua doing this or that. I don't know X as I
The motor is essentially a permanent-magnet stepper motor. The rotor
and stator have just 2 poles each, so the rotor has two stable
positions 180 degrees apart that provide holding torque. Thus, the
motor holds position with no input current for most of each cycle. To
move it, the drive applies
Hi:
Here are some photos of the inside of a quartz clock and some related
patent links:
http://www.prc68.com/I/QuartzClk.shtml
Have Fun,
Brooke Clarke
http://www.PRC68.com
David Martindale wrote:
The motor is essentially a permanent-magnet stepper motor. The rotor
and stator have just 2
It's been a while since I did it, but as I recall, a simple way of
driving the typical motor on a dime store clock is:
FF-Q-)|-MOTOR+
.|
FF-/Q+
The capacitor charges up during
measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Sidereal timekeeping
The motor is essentially a permanent-magnet stepper motor. The rotor
and stator have just 2 poles each, so the rotor has two stable
positions 180 degrees apart that provide holding torque. Thus, the
motor holds
Date: Wed, 18 May 2011 14:09:39
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Sidereal timekeeping
It's been a while since I did it, but as I recall
Analog quartz clocks may be used as slave clocks.
You do not even have to disconnect the quartz movement.
Just find the coil on the motor and drive it with a square-wave of
0.5 hertz,
in series with a capacitor (about 50mfd) and a resistor (about 200 ohms)
Each type of clock is different,
Hi
In a full sized wall clock, most of the power is to the motor. On a wrist watch
- it depends on how well the watch is built.
Bob
On May 17, 2011, at 12:37 AM, Hal Murray wrote:
As an alternative you could build an external circuit (a few uA at 3V
supply) and generate a signal to
Neville and Jim and all,
there are good pictures of tuning fork crystals at
http://en.wikipedia.org/wiki/Crystal_oscillator
I think it is the 8x3 mm in size, which is available from China (10 units for
2.5$ including worldwide shipping). Assuming as a reference the diameter of the
baseplate,
-nuts] Sidereal timekeeping
Jim Lux wrote:
On 5/16/11 2:58 PM, iov...@inwind.it wrote:
Neville,
at present I have not enough skill with micros to solve the problem.
I think I will try modifying a crystal. This would not be that difficult
using
a lapping sheet or the like. And opening the can
-nuts@febo.com
Sent: Tuesday, May 17, 2011 12:27 PM
Subject: Re: [time-nuts] Sidereal timekeeping
Hello list,
I tried that a long time ago, but the trap I went into was that the
capacitance of the 'scope probe was pulling the frequency down, so I ended
with a crystal too high in frequency...
I'm
-azur.fr
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Tue, May 17, 2011 8:27:14 AM
Subject: Re: [time-nuts] Sidereal timekeeping
Hello list,
I tried that a long time ago, but the trap I went into was that the capacitance
of the 'scope probe was pulling the frequency
-
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Tuesday, May 17, 2011 1:22 AM
Subject: Re: [time-nuts] Sidereal timekeeping
Jim Lux wrote:
On 5/16/11 2:58 PM, iov...@inwind.it wrote:
Neville,
at present I
interferometry with aperture synthesis).
YMMV...
Regards,
Jean-Louis
- Original Message -
From: iov...@inwind.it
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Tuesday, May 17, 2011 1:05 PM
Subject: Re: [time-nuts] Sidereal timekeeping
Hi Jean-Louis
On 5/17/11 7:01 AM, Jean-Louis Oneto wrote:
I realized that there was lot of way to avoid this [pulldown] problem,
but as I said, it was a long time ago (around 1976...), I was young and
inexperimented, and I just tried once on an almost broken 5 FF (~$1)
wristwatch, then I decided that the
To: time-nuts@febo.com
Subject: Re: [time-nuts] Sidereal timekeeping
On 5/17/11 7:01 AM, Jean-Louis Oneto wrote:
I realized that there was lot of way to avoid this [pulldown] problem,
but as I said, it was a long time ago (around 1976...), I was young and
inexperimented, and I just tried once
On Tue, 17 May 2011 11:52:53 -0400
Bob Camp li...@rtty.us wrote:
And you want to keep both sides of the tuning fork equal length to roughly
one part in 50,000 when you move it 1 part in 365.
May i ask, why this is important?
Attila Kinali
--
The trouble with you,
and frequency measurement
Subject: Re: [time-nuts] Sidereal timekeeping
On Tue, 17 May 2011 11:52:53 -0400
Bob Camp li...@rtty.us wrote:
And you want to keep both sides of the tuning fork equal length to roughly
one part in 50,000 when you move it 1 part in 365.
May i ask, why this is important
li...@rtty.us said:
In a full sized wall clock, most of the power is to the motor. On a wrist
watch - it depends on how well the watch is built.
Thanks.
I think that means that it's not silly to generate a PPSS (Pulse per Sidereal
Second) signal by counting to 364/365 of 32678 rather than
...@sfr.fr
Data: 16/05/2011 0.14
A: iov...@inwind.itiov...@inwind.it
Ogg: Re: [time-nuts] Sidereal timekeeping
Le 15/05/2011 23:39, iov...@inwind.it a écrit :
I don't think this will work as the divider chain will give wrong length
seconds.
Michael,
I'm just looking for shorter seconds, in order
On Mon, 16 May 2011 00:01:54 +0200 (CEST)
iov...@inwind.it iov...@inwind.it wrote:
Heh.. I cheated and used a 3325B to make whatever frequency we wanted.
(even better, you can use GPIB to change the frequency vs time to make a
clock that displays unusual things like height above horizon or
The background of my request is an OT story. Just to mention briefly, I already
have an ordinary (non-radio-controlled) clock machine which turns a miniature
torsion balance in a sealed glass vessel. It runs on a single AA battery. No
extreme accuracy needed. I wont to modify the rate to
Antonio,
it is quite easy to make an external circuit that uses a 32kHz xtal
and divides
it down to siderial seconds. It is also easy to drive most analog
quartz clock movements from
an external circuit.
Just what signal do you need? What frequency? and what does it drive?
(an alternate
Can't you just use a programmable crystal? Digikey will do this for
you prior to ship. Search on crystal, then under the field type,
filter by Programmed by Digikey. Four types pop up as in stock.
Not sure if they would meet you footprint requirement, but its worth a
shot.
Brent
On Mon, May
On 5/16/11 6:30 AM, brent evers wrote:
Can't you just use a programmable crystal? Digikey will do this for
you prior to ship. Search on crystal, then under the field type,
filter by Programmed by Digikey. Four types pop up as in stock.
Not sure if they would meet you footprint requirement,
Nope - you're right - most don't go below 1MHz. Got a little loose
with my K's and M's I guess. Kinda like - what's 3dB among friends?
My apologies for the stray lead. Thanks for catching it Jim.
Brent
On Mon, May 16, 2011 at 10:21 AM, Jim Lux jim...@earthlink.net wrote:
On 5/16/11 6:30 AM,
Neville,
at present I have not enough skill with micros to solve the problem.
I think I will try modifying a crystal. This would not be that difficult using
a lapping sheet or the like. And opening the can would be quite easy using hot
air. This is the fastest way for me, and the device will
On 5/16/11 2:58 PM, iov...@inwind.it wrote:
Neville,
at present I have not enough skill with micros to solve the problem.
I think I will try modifying a crystal. This would not be that difficult using
a lapping sheet or the like. And opening the can would be quite easy using hot
air.
or a fine
Jim Lux wrote:
On 5/16/11 2:58 PM, iov...@inwind.it wrote:
Neville,
at present I have not enough skill with micros to solve the problem.
I think I will try modifying a crystal. This would not be that
difficult using
a lapping sheet or the like. And opening the can would be quite easy
using
Hi Antonio,
the 32kHz Xtals are 2mm long tuning forks (that is what I believe
although I have not opened one).
You would have very little chance of modifying it and still have
enough Q left for it to oscillate.
As an alternative you could build an external circuit (a few uA at 3V
supply)
As an alternative you could build an external circuit (a few uA at 3V
supply) and generate a signal to inject into the existing Xtal osc with the
Xtal removed.
In a typical battery operated clock, what fraction of the power goes to the
oscillator and counter and how much goes to the motor?
Hi all,
does anybody out there have any ideas as where to find a 32859Hz crystal (1/2
that value would be better) to be used to replace 32768 crystals in ordinary
clocks? I think that 32768 crystals cannot be dragged that much. I've already
read the JimLux article somewhere on the web, but I
Le 15/05/2011 23:22, iov...@inwind.it a écrit :
Hi all,
does anybody out there have any ideas as where to find a 32859Hz crystal (1/2
that value would be better) to be used to replace 32768 crystals in ordinary
clocks?
I don't think this will work as the divider chain will give wrong length
On 5/15/11 2:22 PM, iov...@inwind.it wrote:
Hi all,
does anybody out there have any ideas as where to find a 32859Hz crystal (1/2
that value would be better) to be used to replace 32768 crystals in ordinary
clocks? I think that 32768 crystals cannot be dragged that much. I've already
read the
Hi Antonio:
Another way to do it is to use any common crystal (10 MHz would have
advantages) and a small PIC micro controller to generate the sidereal *
2^15 frequency.
Note this can be done to very high precision.
http://www.prc68.com/I/PIC16F88.shtml#PIT
Have Fun,
Brooke Clarke
jim...@earthlink.net wrote:
On 5/15/11 2:22 PM, iov...@inwind.it wrote:
Hi all,
does anybody out there have any ideas as where to find a 32859Hz crystal
(1/2
that value would be better) to be used to replace 32768 crystals in
ordinary
clocks? I think that 32768 crystals cannot be dragged
On 05/16/2011 12:01 AM, iov...@inwind.it wrote:
I think you're right that you can't drag a 32768 crystal down by one
part in 365. Maybe you could do it by opening the can and putting some
mass on the crystal resonator?
Some mass should be removed, not added. I was considering this
does anybody out there have any ideas as where to find a 32859Hz crystal (1/
2 that value would be better) to be used to replace 32768 crystals in
ordinary clocks? I think that 32768 crystals cannot be dragged that much.
I've already read the JimLux article somewhere on the web, but I
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