how to reduce speed/ amplitude of electronic pendulum??

[Franc Zabkar]

On Sun, 14 Oct 2012 02:32:28 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> put finger to keyboard and composed:

I've only seen one electronic pendulum. it used a sensing coil
to detect the approach of the pendulum, and fired a pulse to
add to the stored energy.

I'm not sure that would work correctly. You want the drive coil to fire at a
fixed frequency. Otherwise, the pendulum would be synched at its lower
native frequency.

Perhaps there are two different design philosophies.

In one case the pendulum is tuned to a frequency of 1Hz and the
electronic circuit functions to compensate for losses due to friction
and drag.

In the second case the electronic circuit provides an accurate crystal
controlled time base and it keeps the pendulum synced to this time
base.

In other words, perhaps in the first instance the pendulum is driving
the clock movement, while in the second case the clock movement is
driving the pendulum.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[William Sommerwerck]

"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message
news:8r5m78hbcm3eqg7kfcm9d1p0hkiqeairie@4ax.com...

On Sun, 14 Oct 2012 02:32:28 -0700, "William Sommerwerck"
grizzledgeezer@comcast.net> put finger to keyboard and composed:

I've only seen one electronic pendulum. it used a sensing coil
to detect the approach of the pendulum, and fired a pulse to
add to the stored energy.

I'm not sure that would work correctly. You want the drive coil to
fire at a fixed frequency. Otherwise, the pendulum would be
synched at its lower native frequency.

Perhaps there are two different design philosophies.

In one case the pendulum is tuned to a frequency of 1Hz and the
electronic circuit functions to compensate for losses due to friction
and drag.

In the second case the electronic circuit provides an accurate crystal
controlled time base and it keeps the pendulum synced to this time
base.

In other words, perhaps in the first instance the pendulum is driving
the clock movement, while in the second case the clock movement is
driving the pendulum.

What you say makes sense -- but the drive circuit will always compensate for
losses, regardless of design philosophy.

Therefore, it makes sense to have the pendulum swing a tiny bit slow, and
have the drive circuit force it to the correct frequency. This would also
make trimming the frequency a simple matter.

 

On Sun, 14 Oct 2012 13:49:46 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message
news:8r5m78hbcm3eqg7kfcm9d1p0hkiqeairie@4ax.com...
On Sun, 14 Oct 2012 02:32:28 -0700, "William Sommerwerck"
grizzledgeezer@comcast.net> put finger to keyboard and composed:

I've only seen one electronic pendulum. it used a sensing coil
to detect the approach of the pendulum, and fired a pulse to
add to the stored energy.

I'm not sure that would work correctly. You want the drive coil to
fire at a fixed frequency. Otherwise, the pendulum would be
synched at its lower native frequency.

Perhaps there are two different design philosophies.

In one case the pendulum is tuned to a frequency of 1Hz and the
electronic circuit functions to compensate for losses due to friction
and drag.

In the second case the electronic circuit provides an accurate crystal
controlled time base and it keeps the pendulum synced to this time
base.

In other words, perhaps in the first instance the pendulum is driving
the clock movement, while in the second case the clock movement is
driving the pendulum.

What you say makes sense -- but the drive circuit will always compensate for
losses, regardless of design philosophy.

Therefore, it makes sense to have the pendulum swing a tiny bit slow, and
have the drive circuit force it to the correct frequency. This would also
make trimming the frequency a simple matter.

To me the way that makes the most sense is to completely uncouple the

two functions. The accuracy of the cheapest quartz movement is far
better than you can get with the most precise pendulum. The most
efficient pendulum is one that oscillates at it's native frequency.
Googeling electronic pendulum drive circuit yields a great deal of
information, including some designs that simply provide a boost to a
pendulum at it's native frequency. Most of the designs did nothing to
optimize drive current.

PlainBill

 

[N_Cook]

<PlainBill@yawhoo.com> wrote in message
news:47co78586ojl4ikafjn43t4qf1fm4ccloj@4ax.com...

On Sun, 14 Oct 2012 13:49:46 -0700, "William Sommerwerck"
grizzledgeezer@comcast.net> wrote:

"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message
news:8r5m78hbcm3eqg7kfcm9d1p0hkiqeairie@4ax.com...
On Sun, 14 Oct 2012 02:32:28 -0700, "William Sommerwerck"
grizzledgeezer@comcast.net> put finger to keyboard and composed:

I've only seen one electronic pendulum. it used a sensing coil
to detect the approach of the pendulum, and fired a pulse to
add to the stored energy.

I'm not sure that would work correctly. You want the drive coil to
fire at a fixed frequency. Otherwise, the pendulum would be
synched at its lower native frequency.

Perhaps there are two different design philosophies.

In one case the pendulum is tuned to a frequency of 1Hz and the
electronic circuit functions to compensate for losses due to friction
and drag.

In the second case the electronic circuit provides an accurate crystal
controlled time base and it keeps the pendulum synced to this time
base.

In other words, perhaps in the first instance the pendulum is driving
the clock movement, while in the second case the clock movement is
driving the pendulum.

What you say makes sense -- but the drive circuit will always compensate
for
losses, regardless of design philosophy.

Therefore, it makes sense to have the pendulum swing a tiny bit slow, and
have the drive circuit force it to the correct frequency. This would also
make trimming the frequency a simple matter.

To me the way that makes the most sense is to completely uncouple the
two functions. The accuracy of the cheapest quartz movement is far
better than you can get with the most precise pendulum. The most
efficient pendulum is one that oscillates at it's native frequency.
Googeling electronic pendulum drive circuit yields a great deal of
information, including some designs that simply provide a boost to a
pendulum at it's native frequency. Most of the designs did nothing to
optimize drive current.

PlainBill

Perhaps you could gate the output drive by a divide by 10 counter on the
clock ouput and only power kick every tenth swing of the pendulum. Would
conserve battery and perhaps less amplitude of swing

 

[William Sommerwerck]

What you say makes sense -- but the drive circuit will always compensate
for losses, regardless of design philosophy.

Therefore, it makes sense to have the pendulum swing a tiny bit slow,
and have the drive circuit force it to the correct frequency. This would
also make trimming the frequency a simple matter.

To me the way that makes the most sense is to completely uncouple the
two functions. The accuracy of the cheapest quartz movement is far
better than you can get with the most precise pendulum. The most
efficient pendulum is one that oscillates at it's native frequency.

ALL pendulums oscillate at their native frequency. They can't help but.

Googeling electronic pendulum drive circuit yields a great deal of
information, including some designs that simply provide a boost to a
pendulum at its native frequency.

You're missing the point. The pendulum presumably drives the clock gears. If
all you care about is "efficiency", switch to an all-electronic clock with
an LCD.

If you're going to power the pendulum electronically, it makes sense to have
a system that keeps the pendulum running at the "right" frequency. The
system I described allows the pendulum frequency to be tweaked without
mechanical adjustments.

 

[Dave Platt]

In article <47co78586ojl4ikafjn43t4qf1fm4ccloj@4ax.com>,
<PlainBill@yawhoo.com> wrote:

To me the way that makes the most sense is to completely uncouple the
two functions. The accuracy of the cheapest quartz movement is far
better than you can get with the most precise pendulum. The most
efficient pendulum is one that oscillates at it's native frequency.
Googeling electronic pendulum drive circuit yields a great deal of
information, including some designs that simply provide a boost to a
pendulum at it's native frequency. Most of the designs did nothing to
optimize drive current.

One trick I have seen used, is to use a magnetic pendulum, and place a
drive-and-sense coil immediately beneath the center of its swing. The
drive circuit senses the beginning of the inductive pulse generated in
the coil as the pendulum swings down towards it, and then sends a
drive-current pulse through the coil to magnetize it and attract the
pendulum magnet just before it "reaches bottom" in its swing.

There are all sorts of tricks you can play with this approach. You
can use a Hall-effect sensor in addition to the coil (separating the
sense and drive functions). If you use a coil, you can detect the
height of the pulse during the pendulum swing in one direction, and
use this as a way of estimating the pendulum's speed... if it's high
enough, you don't need to "kick" the pendulum as hard during the next
swing (don't drive it at all, or reduce the strength or duration of
the drive pulse).

I've seen little "desktop toy" pendulum systems, or "rotating wheel"
toys, which use this approach. They can be rather mysterious, if the
drive/sense electronics are concealed in the base... the pendulum just
keeps swinging, or the wheel keeps rotating, with no visible drive
force and no tick-tock sound.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Dave Platt]

In article <k5hd6s$rts$1@dont-email.me>,
William Sommerwerck <grizzledgeezer@comcast.net> wrote:

You're missing the point. The pendulum presumably drives the clock gears.

I believe that the Klockit pendulum system being described here, does
not use the pendulum to drive the gears. It's described on their web
site as a "pendulum case assembly", into which you insert your
(separate) quartz clock movement. It has a separate battery.

If this is what the OP was using (as I recall), then the pendulum
system is a purely cosmetic add-on to the clock. It plays no part in
the drive, or time regulation of the clock itself... those are
entirely the role of the quartz movement assembly.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

On Mon, 15 Oct 2012 09:21:25 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

What you say makes sense -- but the drive circuit will always compensate
for losses, regardless of design philosophy.

Therefore, it makes sense to have the pendulum swing a tiny bit slow,
and have the drive circuit force it to the correct frequency. This would
also make trimming the frequency a simple matter.

To me the way that makes the most sense is to completely uncouple the
two functions. The accuracy of the cheapest quartz movement is far
better than you can get with the most precise pendulum. The most
efficient pendulum is one that oscillates at it's native frequency.

ALL pendulums oscillate at their native frequency. They can't help but.

Only true if you add the qualifier 'if there are no additional
forces'. A great deal of effort is required to ensure this is true.
Did you ever wonder why the best Grandfather clocks use weights to
provide power?

In a happier time my wife decided we needed a real pendulum clock on
the mantle of our new (to us) home. She picked up one (made in Korea)
that required monthly winding. With a little care I could adjust it
so it was correct at the begining of the month and again at the end of
the month. The force provided by the spring changed depending on how
tight it was, this changed the force on the escapement, which changed
to force applied to the pendulum. The clock would gain time at the
beginning of the month and lose it toward the end of the month.

Look attractive? Yes. Sound good? Definitely. Keep good time - no
way.

PlainBill

Googeling electronic pendulum drive circuit yields a great deal of
information, including some designs that simply provide a boost to a
pendulum at its native frequency.

You're missing the point. The pendulum presumably drives the clock gears. If
all you care about is "efficiency", switch to an all-electronic clock with
an LCD.

If you're going to power the pendulum electronically, it makes sense to have
a system that keeps the pendulum running at the "right" frequency. The
system I described allows the pendulum frequency to be tweaked without
mechanical adjustments.

 

[William Sommerwerck]

What you say makes sense -- but the drive circuit will always
compensate
for losses, regardless of design philosophy.

Therefore, it makes sense to have the pendulum swing a tiny bit slow,
and have the drive circuit force it to the correct frequency. This
would
also make trimming the frequency a simple matter.

To me the way that makes the most sense is to completely uncouple the
two functions. The accuracy of the cheapest quartz movement is far
better than you can get with the most precise pendulum. The most
efficient pendulum is one that oscillates at it's native frequency.

ALL pendulums oscillate at their native frequency. They can't help but.

Only true if you add the qualifier 'if there are no additional
forces'. A great deal of effort is required to ensure this is true.
Did you ever wonder why the best Grandfather clocks use
weights to provide power?

No, I never wondered, because I knew why. And it's energy, not power, by the
way.

 

[N_Cook]

<PlainBill@yawhoo.com> wrote in message
news:1ker78d72qtmc4cfo109qbut2rgp9jlibf@4ax.com...

On Mon, 15 Oct 2012 09:21:25 -0700, "William Sommerwerck"
grizzledgeezer@comcast.net> wrote:

What you say makes sense -- but the drive circuit will always
compensate
for losses, regardless of design philosophy.

Therefore, it makes sense to have the pendulum swing a tiny bit slow,
and have the drive circuit force it to the correct frequency. This
would
also make trimming the frequency a simple matter.

To me the way that makes the most sense is to completely uncouple the
two functions. The accuracy of the cheapest quartz movement is far
better than you can get with the most precise pendulum. The most
efficient pendulum is one that oscillates at it's native frequency.

ALL pendulums oscillate at their native frequency. They can't help but.

Only true if you add the qualifier 'if there are no additional
forces'. A great deal of effort is required to ensure this is true.
Did you ever wonder why the best Grandfather clocks use weights to
provide power?

In a happier time my wife decided we needed a real pendulum clock on
the mantle of our new (to us) home. She picked up one (made in Korea)
that required monthly winding. With a little care I could adjust it
so it was correct at the begining of the month and again at the end of
the month. The force provided by the spring changed depending on how
tight it was, this changed the force on the escapement, which changed
to force applied to the pendulum. The clock would gain time at the
beginning of the month and lose it toward the end of the month.

Look attractive? Yes. Sound good? Definitely. Keep good time - no
way.

PlainBill

Googeling electronic pendulum drive circuit yields a great deal of
information, including some designs that simply provide a boost to a
pendulum at its native frequency.

You're missing the point. The pendulum presumably drives the clock gears.
If
all you care about is "efficiency", switch to an all-electronic clock
with
an LCD.

If you're going to power the pendulum electronically, it makes sense to
have
a system that keeps the pendulum running at the "right" frequency. The
system I described allows the pendulum frequency to be tweaked without
mechanical adjustments.

Thats why fusees were invented, but could only compensate to a certain
extent

 

[William Sommerwerck]

units analysis ... probably isn't the right term, but I can't think of
what it is.

Dimensional analysis?

That's it! Thank you.

 

[Mike]

In article <k5e8vi$27d$1@dont-email.me>,
William Sommerwerck <grizzledgeezer@comcast.net> wrote:

units analysis ... probably isn't the right term, but I can't think of what it is.

Dimensional analysis?

--
--------------------------------------+------------------------------------
Mike Brown: mjb[-at-]signal11.org.uk | http://www.signal11.org.uk

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

[Leif Neland]

Efter mange tanker skrev N_Cook:

William Sommerwerck <grizzledgeezer@comcast.net> wrote in message
news:k5a0hr$64d$1@dont-email.me...
Excuse my ignorance, but how does your circuit
know when to apply a kick?

It doesn't.

Assume the pendulum is supposed to have a period of one second. You design
it to be a little bit longer, then make the driver circuit operate at
exactly one second. The pendulum will eventually sync with the driver.

Remember when TVs had hold controls? The principle is the same. The
most-stable operation is obtained when the oscillator runs a tiny bit slower
than it should, with the sync signals "kicking" it at the right frequency.



Human clocks are the same. Put a human in a cave, out of touch with the
outside world, and his natural day-length reverts to about 24.5 to 25 hour
days, requires the sun etc to sync him to 24 hour days

Not all people "run slow". Some "run fast". These are the people with
the nasty habit of waking up at 5AM pestering the other half until the
early birds go to sleep when the late risers want to have fun.

If you are locked in the office/shop/factory all the hours with
daylight, and never seeing the light of day during the winter, you can
get depressed; this can be reduced by, in the morning, looking into a
strong "wake-up-lamp" designed to have the spectrum of sunlight.



--
Husk křrelys bagpĺ, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.