Pendulum Clock with Atomic Precision 213
u19925 writes "Now you can get atomic clock precision out of your grandma pendulum clocks. Here is how it works: There is a camcorder fitted inside the clock which monitors the pendulum swing. It has an atomic clock signal receiver. It compares the pendulum swings with the atomic signal hearbeat. The camcorder also has an arm. If the pendulum clock drifts, then it uses its arm to push or pull the pendulum to make correction." It's not an April Fool's joke, but it is rather impractical.
Regularity? (Score:5, Funny)
Re:Regularity? (Score:2, Funny)
Pushing will protect you
Pushing is the answer
Humans must be pushed
Grandma is protected
Grandma has gone down the stairs
Here's the link (Score:1, Redundant)
Re:Here's the link (Score:1, Offtopic)
Re:Here's the link (Score:1)
Why not magnets? (Score:5, Interesting)
Re:Why not magnets? (Score:4, Insightful)
okay, the real question is why do this at all?
Why at all? (Score:1)
Re:Why not magnets? (Score:5, Funny)
Geez Batman, how are we going to figure this one out?
Quick Robin, to the article!
There is a growing shortage of people who are familiar with the workings of the large mechanical clocks on churches and public buildings, as routine maintenance tasks such as winding the clocks become automated. Yet they still need to be put forward an hour in spring and moved back again in the autumn without damaging their fragile mechanisms, some of which are 250 years old.
Re:Why not magnets? (Score:2)
Heck, there is a growing shortage of people who can set the clock on the camcorder needed to adjust the timing of their pendulum clock!
Re:Why not magnets? (Score:2)
Cheaper/easier solution: Put a big honking neon sign below the clock that says "[name of time zone here] Standard Time." Require other people to remember to add an hour for "summer"/"daylight" time when appropriate.
Re:Why not magnets? (Score:1, Troll)
Re:Why not magnets? (Score:3, Interesting)
Sure this pendulum thing seems kind of silly, but may be the feedback mechanism could inspire some new neural network neuron - a precursor to true AI!
You could be just trolling asking a ques
Re:Why not magnets? (Score:1)
Re:Why not magnets? (Score:3, Insightful)
Why not an active base instead? (Score:2)
Re:Why not an active base instead? (Score:2)
Easy (Score:2)
If an active base works for something this large, it can be scaled down, I'm sure.
Re:Easy (Score:2)
Why travel anywhere if you can just move the universe?
move the universe...now you're thinking (Score:2)
Re:Easy (Score:2)
I rather suspect a two-hundred year old building wouldn't put up with that abuse for very long.
Re:Why not magnets? (Score:5, Interesting)
These are not grandfather clocks, they are large public clocks and the movements are very old. The objective is to avoid human contact since people tend to break them advancing or retarding them for summertime.
So this is not a Rube Goldberg device, it is a piece of conservation technology :-)
The Westminster Tower Clock, with its famous bell 'Big Ben' is kept accurate by a warden who runs (ok shuffles, most jobs of that type go to aged war veterans) up a flight of stairs and adds or removes pre-decimal pennies from the pendulum bob. Ah you cry, but the time taken by a pendulum does not depend on the weight, well yes but the pennies slightly raise the center of gravity of the bob you see...
The camera bit sounds a little over the top, surely an led and a receiver???
Re:Why not magnets? (Score:5, Interesting)
I'm guessing that you mean an opto-isolator type circuit. Other possibilities, a magnet embedded in the pendulum and a hall-effect device near each end of the path of the swing or a coil attached to a circuit which will detect the inductance change caused by the pendulum's proximity, or just let the pendulum brush across a contact pair and complete a circuit.
Re:Why not magnets? (Score:2)
i wouldn't classify that as an opto-isolator type circuit, but i suppose you might
Re:Why not magnets? (Score:2)
Re:Why not magnets? (Score:2)
Re:Why not magnets? (Score:2)
Re:Why not magnets? (Score:2, Informative)
Slightly off-topic, but interesting none the less: a normal pendulum does not take the same time to reach the bottom no matter where it is released, contrary to popular belief. The correct curve is actually an inverted cycloid, and the finding of this curve was deemed the 'tautochrone problem.' Obligatory mathworld linkage: Tautochrone Problem. [wolfram.com]
O
Re:Why not magnets? (Score:2)
The original article makes no mention of a camera -- this appears to be sloppy summarizing on the submitter's part. The article says it's done with "infrared sensors", which sounds saner.
That's
Webcam is simple and cheap (Score:2)
Why not eliminate daylight savings? (Score:2)
So this is not a Rube Goldberg device, it is a piece of conservation technology :-)
Why not eliminate the Rube Goldberg device and get to the root of the problem: Eliminate DST [standardtime.com]
Re:Why not eliminate daylight savings? (Score:2)
(based on as assumption that 300,000,000 people each leave 2 60W bulbs burning when they are awake at night). You can quibble about the numbers if you want, but the point of a massive energy saving is the
Re:Why not magnets? (Score:1)
Re:Why not magnets? (Score:2)
Re:Why not magnets? (Score:5, Insightful)
The New Scientist article doesn't mention any camera's, camcorders (why should you record this anyway, it's over in a second
Still, this whole project is of course nuts. You love clocks (like I do !!) and than you have the honor to wind them every day, every Sunday at noon, or
Anybody can read the time from his cellphone. And using a GPS for the time-reading
Re:Why not magnets? (Score:2)
'Cause that's just not geeky.
Re:Why not magnets? (Score:1)
Re:Why not magnets? (Score:2)
Well if your going through all the trouble of retrofitting your antique timepiece with a nifty little oversight device, replacing/modding the pendulum is probably doable.....
New low for /. (Score:1, Offtopic)
Editors forgot how to insert links.
Any "HTML Programmers" care to help?
Re:New low for /. (Score:1, Offtopic)
For those of you too lazy to copy and paste... (Score:2, Informative)
Now you can get atomic clock precision [newscientist.com] out of your grandma pendulum clocks. Here is how it works: There is a camcorder fitted inside the clock which monitors the pendulum swing. It has an atomic clock signal receiver. It compares the pendulum swings with the atomic signal hearbeat. The camcorder also has an arm. If the pendulum clock drifts, then it uses its arm to push or pull the pendulum to make correction. " It's not an April Fool's joke, but it is rather impract
Parent is not a troll - Explanation moderators. (Score:3, Funny)
FIX DA LINK! (Score:2, Funny)
Sigh. I'd love to get a href, but where would I put it?
Re:FIX DA LINK! (Score:1, Funny)
Well, one suggestion [goatse.cx] immediately springs to mind...
speaking of impractical (Score:1)
Re: (Score:1)
Rube Goldberg (Score:4, Funny)
Re:Rube Goldberg (Score:2)
Erm... (Score:1, Redundant)
Ditto for the link (Score:2)
Try this [newscientist.com]
I was going to do this (Score:5, Interesting)
My plan was to put a magnet on the pendulum and then put the regulation mechanism on the reverse. This would measure each swing of the pendulum from the emf induced in a coil on the back of the clock. This would also be used to advance or retard the pendulum if necessary.
No you werent (Score:4, Funny)
C'mon, admit it.
Re:I was going to do this (Score:2, Interesting)
The Preview Button (Score:1)
...is there to prevent posters from making glaring errors in their submissions.
Maybe the editors should get one of those too. It's pretty handy for us peons who make mistakes all the time...
This just in ... (Score:1, Funny)
Atomic HTML checker? (Score:1)
More info and oblig typo joke (Score:1, Redundant)
Latency? (Score:5, Insightful)
Re:Latency? (Score:5, Interesting)
My computers and other appliances use crystal clocks which are very precise. But they slowly drift, and no correction is applied (except when I net sync my computer) so they drift and keep on drifting. Precise, but not accurate.
The net connection/camera/lever arrangement may not be as precise as an atomic clock, but it will be very accurate. See how it works? ;^)
Re:Latency? (Score:4, Interesting)
Then there's the story about the engineering students that noticed their professor never wore a watch, so they rigged something up to the power line to alter its frequency. They ran the clock fast he kept talking faster and faster to keep pace with the clock. I forgot how far they got before he noticed, but from what I remember, they had him compressing the class pretty much.
Re:Latency? (Score:4, Funny)
Date: Tue, 14 Dec 1993 13:50:47 PST
From: hcate.OSBU_North@XEROX.COM
Subject: Life 3.9 A collection of clean humor gathered on: 16 Jun 88
I got this from the June issue of "Discover"....
particularly satisfying incident in the early 1970's involved a math
professor who annoyed students by his mechanical, predictable
approach to teaching - his lecture notes were straight from his
book. One student got hold of a device that changed the normal
frequency in an electrical outlet to any desired value. He plugged
the classroom clock into it and, over serveral weeks, upped the
speed -first by 10 percent, then 12.5 percent, then 15 percent.
Each day the frazzled professor raced through the tried-and-true
lecture faster and faster, until finally he was reduced to
fast-forward gibberish.
Re:Latency? (Score:2)
School clock systems (at least back in my day :^) used a central signal with the power line as a carrier. Once a minute the cental time clock would send a signal to advance a minute. There was also a reset and advance hour signal so they could fix borfed clocks and leap forward/fall back.
Add a line filter to the clock, inject your own signals, piece of pie!
As for Brazil, they're in a bad way. That sort of variation shows that they're no
Re:Latency? (Score:2)
Sometimes two wrongs do make a right. On average.
Re:Latency? (Score:2)
Re:Latency? (Score:1)
OK, let's assume a worst-case latency of 1 second. Even with that extremely pessimistic assumption, you've still got a clock that is never more than a second off. Hell, assume that it doesn't actually adjust the pendulum until it's 3 seconds off; you've still got a timekeeper that will never be more than 4 seconds wrong. For an antique analog clock, you'd be crazy not to take that.
Compare that to my wristwatch, which is a far more capable timer than a pendulum clock. Even a quartz clock drifts over time;
Re:Latency? (Score:2, Interesting)
From the article:
"If the antique clock loses time, a small piston speeds it up with a gentle nudge on the pendulum; if it runs fast, the piston slows it down. Each day, the clock is kept accurate to a tenth of a second. "
duh... don't think that the precision is atomic..
what a crappy title?? "Pendulum clock with atomic precision"
also crappy description about camcorders and stuff that are never described..
the idea of this system is to prevent antique clocks from
It's not atomic precision.. (Score:3, Insightful)
Re:It's not atomic precision.. (Score:2, Insightful)
Hah! English clock robots! (Score:1)
I'm not sure why. Probably because it's British.
This was in Scientific American (Score:3, Interesting)
Re:This was in Scientific American (Score:2)
I've been fantasizing about updating this for modern technology, using the pulse-per-second output from a GPS receiver. You could even graft this on to the quartz system, using the quartz crystal as a temporary backup for when the
Re:This was in Scientific American (Score:1)
It always amazes me how people always invent ideas that have been around for a while. Temporal chauvanism!! ;-)
RTFA people (Score:5, Informative)
Nowhere in the article are the words 'camcorder', 'grandma', 'arm', etc.
It wasn't designed to fit into a grandmother clock and it certainly doesn't use a camcorder. It uses an infared sensor to sense pendulum location and a 'piston' to modify pendulum swing, and it is being used to automate maintenance on large clocks in churches, etc. It can also set the clock ahead and back an hour for daylight savings time.
Gotta be the worst case of can't be bothered to RTFA I've ever seen.
Now, anyone who thinks it would be better to replace the clocks in Big Ben with some modern electronic thing... well... probably ought to be shot. This doesn't seem like a bad way to get those big clocks to operate a good long time without human intervention.
Re:RTFA people (Score:1)
Digital Big Ben? (Score:1)
More RTFA (Score:4, Funny)
TFA also states that because we're talking about historic clocks, they can't go drilling holes into them and bolting stuff on. Hence the Rube Goldberg nature of these non-invasive mods.
Xix.
This is awesome... (Score:5, Funny)
Re:This is awesome... (Score:2)
We are the borg... (Score:4, Funny)
Not as impractal as it first looks (Score:5, Informative)
The clocks that are being regulated are tower clocks, they are observed by hundreds if not thousands of people a day. It would be nice to know that they are on time. It would also be a crime to rip out the old pendulum movement and replace them with an electric movement. Another feature is that the old antique system can run for several days in the event of a power failure, it just won't be quite as accurate.
The movements in these clocks are heavy cast iron units with large gears and very heavy pendulums. Using a magnet system to attempt to influence the timing rate would probably prove ineffective. However using some sort of system to raise or lower the pendulum by just a couple of millimeters will affect the timing rate by several seconds a day.
These clocks used to be wound once a week by hand and the time would have been reset at that time. These days most of these clocks have been converted to an automatic winding system, thus they see much less hands on maintenance, automatic systems for regulating the clock become much more attractive.
As a side note, the tower clock in London, commonly known as "Big Ben" ("Big Ben" is really the name of the bell that is used to count the hours) is regulated by adding or removing one or two old English Pennies, the one that were about the size of an old American Silver Dollar. The clock is regulated to be as on time as possible on the Queens Birthday and on New Years Eve.
Going even further afield some of you might get a kick out of the elaborate astronomical clocks that were designed in the 1800's. These were astonishing pieces of engineering that have been known to take an astronomer to figure out all of the settings required to set the clock.
I guess my passion for my vocation is showing, I hope that I was able to add something of interest.
Chronos
Re:Not as impractal as it first looks (Score:1)
It's not a clock... is it? (Score:2, Insightful)
Does that seem really frivilous to you too? This barely fits under "Stuff that matters"
Hope no one uses these clocks... (Score:3, Funny)
The piston will gradually stop the pendulum over 20 swings or so, avoiding any sudden forces. Then, 11 hours later, when it will be 1 pm British Summer Time, the piston will gently set it ticking again
So if lightning strikes the clock at 8:00 am, it will be stopped at 1:00, and no one will be able get their time machine back to the future...
Ultra-accurate mechanical clocks (Score:5, Interesting)
Re:Ultra-accurate mechanical clocks (Score:2)
When the clock first was announced, I remember reading that the point of it was not to keep accurate time, but to figure out how to create a device that could operate continuously for 10,000 years, surviving the changing social, political, technical, economic, and sociologic landscapes.
Today, after reading the site at length it seems they are using a traditional oscillator steered by the rotation of the earth. That's many orders of magnitude less accurate tha
Pentium Clock?? (Score:2)
So I'm thinking to myself, why would someone make a clock with a Pentium in it? What would be the point? Some kind of wi-fi enabled clock that turns on the wi-fi enabled coffee machine in the morning?
Then my brain woke up....
Long ago in Sci Am (Score:2)
Camcorder? (Score:3, Informative)
And why use a piston to change the swing? What's wrong with an electromagnet which wouldn't need to actually touch the pendlum?
Nick...
Atomic clock precision? (Score:2)
Seems like a quartz would do better than that!
Overengineered.
How ist this new or interesting? (Score:2)
or... (Score:2)
News flash (Score:2)
Conceptually.... (Score:5, Informative)
Consider where I work - we have a very accurate 10 MHz reference to sync all our RF gear to. We need that ref to be tracable to the National Bureau of Standards. Now, it would be somewhat impractical to check with the Bureau 10 million times a second (anybody want to run a fiber from Boulder to Wichita just for the time sync?).
Before I go on, let me point out the difference between precision, accuracy, and repeatability.
From a metrological standpoint, having more accuracy than repeatability is useless. Having more precision than accuracy is also useless. (Ignoring tricks like averaging for the moment.)
Back to the example. What we do is to have a very high precision and stable oscillator (we used to use a rubidium standard). It has a long term stability of about 10E-9 and a short term stability of 10E-12. In other words, over a short period of time the thing will drift not more than one part per trillion, and over the long term (days) it will drift about one part per billion.
Now, that is running next to a GPS receiver that gives us a time tick synced to the Bureau. Every second the GPS time is compared to the local time standard, and an error value is computed. That error value is averaged over a long period of time, and used to gently tweak the rubidium standard. Thus, over the long run the drift is reduced to level of the cesium clocks, about 10E-13.
So we have atomic clock accuracy but rubidium clock precision and repeatability.
Now, if you used the same sort of technique on a pendulum clock - measure the error between the clock and the GPS, average, filter, and apply - you would have atomic clock accuracy with pendulum clock precision. Granted, I would not want to use the clock's time for reporting astronomic phenomena where the precision must be very high, but for normal use this would be quite good enough.
That's the point! (Score:4, Funny)
Well, that's the point, isn't it? I mean, what's the point of being a geek if you can't do geeky, pointless things?
would it be entirely heretical (Score:2)
Or is the tremendous effort to keep the weights/pendulum the 'driver/regulator' for the clock mechanism the point? Maybe I'm just a mechanical clock philistine.
WTF? (Score:3, Insightful)
That's not having an atomically precise clock; that's using an atomically precise clock to automatically adjust your not-so-precise clock.
Why do you need a camcorder? (Score:3, Interesting)
This is not a pendulum clock. (Score:2)
Does this mean that I've bred a superhorse when I put a race horse in a trailer and drive him cross-country at 80mph?
Stupid headline detracts from otherwise neat hobby-hack.
Re:Why a camera? (Score:1)
Re:A clock is impractical? (Score:2, Informative)
Here is a good link with examples of why pendulum (gravity) based systems wouldn't be too practical.
http://media4.physics.indiana.edu/~kostelec/mov