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Ask Slashdot: Alternatives To "Atomic" Clocks?
Tony Isaac writes: "Atomic" clocks that you can buy in stores synchronize time using the WWVB shortwave band from NIST in Boulder. The problem is, this signal is notoriously weak, making these clocks very sensitive to interference by other RF or electronic devices, or less-than-ideal reception conditions. In many locations, these clocks are never able to receive a time signal, making them no better at timekeeping than a cheap quartz clock. There are other ways to synchronize clock time: NTP over WiFi, GPS, or cellular. The cheapest clocks that use NTP over Wi-Fi cost around $400. Really? And while there are plenty of GPS-enabled smartwatches in the $100 price range, there don't seem to be any similar wall clocks. Are there any reasonably-priced wall clock alternatives, that use something other than shortwave to set the time?
No wait, it's still atomic
“He’s not deformed, he’s just drunk!”
I think the problem that you're having with finding such a device is that it's simply not necessary at this point. People use their phones and such for the time. If they're buying an alarm clock, it's generally accurate enough as is, and if they're putting a wall clock up they're doing it for the ambiance as much as having the time available.
GPS indoors is iffy anyways.
I don't read AC A human right
The Global Positioning System can do more than just tell you where you are. It can also tell you when you are.
If it weren't for deadlines, nothing would be late.
"Are there any reasonably-priced wall clock alternatives, that use something other than shortwave to set the time?"
Buy an Amazon fire for under 50$ or any cheap tablet and use one of the clock apps.
WWVB Coverage Maps:
http://www.nist.gov/pml/div688/grp40/vb-coverage.cfm
it is not about being that accurate. it is about being accurate and no need to set it ever.kinda convenient
As cheap as 50$ on ebay, some are GPS-disciplined. Small, available. About the same tech currently on the GPS satellites themselves.
I have seen quite a few very well done setups that consist of a Raspberry Pi (or a clone), and a monitor or cheap HDMI TV.
If you want an analog clock, and not just a digital display of one, then you have a harder job cut out for yourself.
If you don't need real hands, you can buy inexpensive Android tablets for $25. Or buy a $300 tablet with a cracked digitizer for $30 (make sure the display is fine) and stick it in screensaver mode. (You can use a bluetooth mouse to operate it.)
Oh, don't do this if you're married and the clock is for one of the "good" rooms. B-)
In the U.S. it is extremely accurate. Any analog clock with a regular synchronous motor or digital driven by line frequency will keep near perfect time if the power doesn't cut off.
“He’s not deformed, he’s just drunk!”
I was just reading an article somewhere about cheap 40$ chinese tablets... not much use as tablets... but for something like this... you'd probably be able to set it up 'just so'.
a clock app, with wifi sync is trivial. a few settings to keep the screen on, and you'll leave it plugged in 24x7...
Clockmaker here, fix things like this for a living.
There is a simple analog battery movement with a secondary clock inside that resets the clock for DST and back again. They work well, are reasonably accurate and inexpensive. Pretty much a "replace single AA battery one a year and ignore it" movement. I have replaced several of the old "Atomic" movements with these.
If you want digital, we call them cell phones these days. :)
:)
Just buy a cheap DVB-T dongle like the RTL2832U and use any TV Broadcast to synchronize your NTP on it. Bonus you can play with GnuRadio for the same price. https://wiki.gentoo.org/wiki/T...
Cheapo tablet with custom clock, or being pi day get a raspberry pi or arduino and roll your own. Perhaps driving Nixie tubes.
Silence is a state of mime.
Maybe you can build a *transmitter* for DCF77 to re-distribute accurate time indoor?
WWVB transmits on 60KHz. This is longwave not shortwave - The wavelength is 5 kilometers.
To avoid seeing this message again, always shut down your computer properly by selecting Shut Down from the Start Menu.
And let it sync to an internet time server.
I've never had a problem with interference (*) that repositioning my atomic clock did not fix. Good models have a signal strength meter. Another thing to note is that you don't even need constant WWV reception. Good clocks will sync up when WWV can be detected. For well over a decade, my clock has never off by even one minute. It does not display seconds. Its battery consumption is also ridiculously low: 2 AAA cells last 2 years. So don't give up easily. Find a clock online for $50-100 and see how it goes. If you're truly stuck return it.
(*) 15 years ago I had 2 or 3 desktops that were always powered on, and they generated a lot of interference. Now I have one desktop that I rarely power on. The laptop, tablet, smartphone, and other devices don't make a dent in WWV reception.
Location: Michigan.
>" In many locations, these clocks are never able to receive a time signal, making them no better at timekeeping than a cheap quartz clock"
Yep. In the Mid-Atlantic (east coast) the signal is very weak and easily overpowered by just about anything. I have 7 atomic clocks in my house. Only 4 reliably get a signal and the other 3 have to be moved to different rooms to sync, which is very annoying. And the power/reliability changes pretty greatly throughout the year with the seasons.
There was a proposal once to add another WWVB transmitter to help but it never happened. I don't know why there isn't a standard based on FM radio- since just about all the FM stations now broadcast digital information, including the time. It is cheap and simply technology. GPS is not generally a good option because it doesn't penetrate buildings well and they and WiFi clocks are complex and expensive.
... but I kept losing it.
Anyway. Pi 2, $70 screen, $20 case. 5v adapter. Done.
Or a burner phone.
Ex: AT&T GoPhone - Motorola Moto E, 8gb memory, no-contract, Android Lolipop 5.0: $29.99
That gets you a battery-backed clock with a nice LCD display that includes GPS, WiFI, and Cellular. Build a little wooden frame or something for it, run a long usb cord to power, and plug it in. I'm certain there are loads of "dashboard" or screensaver style apps that'll display a clock and keep the screen on.
I'm honestly not sure why people aren't abusing these things more. That's SUPER cheap for what you get.
Just get a quartz clock and calibrate it.
People working on trains and airplanes etc. have to (or at least had to) get their watches calibrated. I remember calibrating my Seiko quartz watches myself back then (1970) to +/- 1 second a month. I could probably have done better.
http://tf.nist.gov/general/pdf...
Everything I write is lies, read between the lines.
I basically just wait two or three years and the tweak it manually. When I oversleep my alarm for an hour every morning, getting the number of seconds right isn't high on my priority list.
Argh... meant to include a link. The phone mentioned is currently onsale at bestbuy for $29.99. Other places, YMMV, but there's often something similar for a similar price.
Wait! I thought he already left...
You kids. in my day we used a schmitt trigger, a resistor, and a capacitor to keep time and we glad to have it. My grandfather used to feel his pulse and bang on a hollow log, so we had it easy. Atomic clocks. Luxury!
Some drink at the fountain of knowledge. Others just gargle.
I don't know if it's actually accurate or not, but it sure looks accurate.
Dear Slashdot: next time you want to mess with the site, add a rich-text editor for comments.
Are there any reasonably-priced wall clock alternatives, that use something other than shortwave to set the time?
Thousands of them, and they're very cheap! They use your hand to set the time by either pushing some buttons or turning a dial.
Glad I could help.
If you plan on building it yourself, there are plenty of accurate oscillators out there at ~100ppb. After a year, at worst you would be off by a few seconds. You would want to make use of a GPS PPS signal to perform the initial calibration but from then on it could run completely isolated from wireless and powerline references signals.
Here is an example oscillator rated for 50ppb http://www.conwin.com/datasheets/tx/tx395.pdf. It can be found on Digikey.
Changing the time twice a year, how fucking lazy are you?
Only the State obtains its revenue by coercion. - Murray Rothbard
Here's one on Etsy that can use NTP, GPS for $70. there's other for $30 out there if you google.
https://www.etsy.com/listing/2...
Some drink at the fountain of knowledge. Others just gargle.
The reason these things are expensive is because it's neither cheap nor easy to "just" implement something with WiFi-to-NTP. You need some sort of an interface to enter WiFi settings, you almost need an entire OS with a DHCP daemon, TCP stack, NTP daemon, you need the WiFi chip and be able to power it (you would hope) using a battery for ~1y. Then you also need a way to fix your clock either using a stepper motor or some sort of time stretching mechanism (where you ignore or add a number of ticks until you have 'corrected' the thing). Then you have to go through FCC regulations because you're creating a transmitter and that will set you back a few $1000's and months of engineering time. That's your entry cost without any ongoing 'tech support' you have to have live for people that can't figure out the thing, security updates (as if) and time zone and daylight savings management/updates.
That's a LOT to get done, even if you boot for a few minutes every 24h to sync the time (and what if you don't have a WiFi signal right then and there) and your market for that tech will be relatively low; most people don't mind spending 1 minute every few months fixing their $5-25 clock, having them spend more money only to get the privilege of changing their battery just as often as they need to change the time is not worth it, the product is dead before you even have it marketed.
If you need such accurate clock, they do exist, they are expensive because the people that need them neither see the direct cost nor have the objection to pay thousands for an accurate clock. The other 'markets' are so niche they already have custom products that don't rely on buggy WiFi/TCP/OS implementations.
GPS has similar cost problems as far as the tech goes, it takes too long to lock onto the required GPS satellites especially indoors where it just becomes a very expensive broken clock.
Custom electronics and digital signage for your business: www.evcircuits.com
That's how the banking system does it. The chips are cheap. If your house clock has to have better accuracy than 1 billionth of a second, then you need to re-prioritize. Heck, if your house clock is quartz based and you can't afford to lose a second per month on what you're looking at to cook and watch your favorite tee vee program and get to work on time, it's still bad.
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
The modern clock chips (eg the Maxim DS3231) are incredibly accurate, eg around a minute per year without user calibration.
http://theradioboard.com/rb/vi...
Alternatively there are many projects using a cheap GPS module to provide a time and date readout.http://geoffg.net/GPS_Synchronised_Clock.html
I'm not sure about commercial products though, sorry.
Changing the time twice a year, how fucking lazy are you?
Exceptionally so! :D
Actually the only analog clock left in my life is one that hangs on my office wall.
I never use it, but it came with the office and I can't be bothered to take it down.
I simply never set or adjust it. Eventually other people notice it's wrong or the battery is dead and fix the problem for me.
But I suppose the company and that clock may outlive my employment there, in which case the incorrect clock will become my replacements problem, and at least for me the problem will then be solved once and for all.
OP is obviously assuming that you'll leave the cell network connected to keep the time correct. That's the whole point of using a phone. Nobody is tracking a burner phone that has never been used, and even if somebody does bother to track it, what are they going to see?
-- Let us endeavor so to live that when we pass even the undertaker shall be sorry. -- M. Twain
Why that accurate? It's an illness that, as of yet, has no cure.
even without a sim card you should get wifi and use NTP. Also my phones have not been bad. Like "cheap quartz clocks" they are still pretty accurate. Seconds a month for cheap ones. Not really any real world case where it needs to be better.
If information wants to be free, why does my internet connection cost so much?
Chip Scale Atomic Clock - OK, at $1500 it's not super-cheap, but it's your own, it will work whether there is Internet or not. Heck, it will work whether there's civilization or not! Imagine having accurate time during the zombie apocalypse.
"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
https://www.google.com/search?...
An ESP8266 module with an LCD or LED display.
You would need an ESP module like the ESP-07 or ESP-12 with multiple I/O pins or a NodeMCU board to drive the display, but you can program it to sync with a time server every day or so over your wireless network.
You can add a DS3231 precision real time clock chip (cheap breakout boards are available on eBay) for better accuracy.
It's not just twice a year for daylight savings. My bedside clock is a pain because it's always out a couple of minutes. I don't know why. I set it to the correct time and within a couple of weeks it's a minute behind. By the time it's time to change the clocks it's about three minutes slow. And yes it's a digital clock. It doesn't bother me enough to always move the time forward. But it would be nice if once a week or even once a month if it would contact a time server and adjusted itself.
Then there are times when the power goes out. It'd be great not to have to go around and set the clocks on everything if they could just connect to a time server and set themselves. My bedside clock has a good battery and keeps the time when the power is out so I normally don't have to set that. But other clocks need to be reset.
Having an open time server for devices to connect to as part of router would be a neat thing so that you wouldn't need to set up devices to connect to your network in order to get to the Internet. Basically have a automatic guest network called 'TimeServer' that fire walled off from everything else. The router would get the time itself from a server and run a time server only accessible on this guest network. Then if a person has WiFi at home then all they would need to do is turn on this feature and any devices would be able to update their time.
Or just buy a cheap tablet, install Timely or My Alarm Clock and mount it on the wall
Total cost: About $50-$70
Total headache: None
LOL!
http://www.buxtronix.net/2015/...
Perl Programmer for hire
It's not just twice a year for daylight savings. My bedside clock is a pain because it's always out a couple of minutes. I don't know why. I set it to the correct time and within a couple of weeks it's a minute behind. By the time it's time to change the clocks it's about three minutes slow.
Obviously your clock is in a chronometric pocket where time runs a little more slowly.
When our name is on the back of your car, we're behind you all the way!
Get the cheapest Android tablet. Root it. Connect to local WiFi. Install ClockSync, some nice-looking clock and a blanking disabler. Hang on the wall.
There. NTP-synchronized wall clock.
(root is needed so that ClockSync could sync time without user interaction.)
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
The next logical step after atomic clocks seems to be hydrogen clocks, or "H-clocks" as they are known.
Better still, make a Pi into a Stratum 1 server:
http://www.satsignal.eu/ntp/Ra...
$400? No way!
What does WWVB stands for? I cannot find using my favorite search engine.
You can sync your computer or smart phone directly with NIST (aka WWV) by visiting http://www.nist.gov/pml/div688/grp40/its.cfm and selecting one of the sync options. The screen saver will work as your 'clock'.
"...and I can't be bothered to Take it down." The time you spent writing that was enough time to take it down. Sweet bejeebus, I've spent too many years building tools for internal customers who invent problems that take longer to verbalize than they do to simply work around.
Funny, because I have a cheap wall clock (less than $10) that I bought at Lowe's a few years ago and it keeps time perfectly.
So, your complete time solution includes a webcam in the antipodes, aimed at a second sundial.
Most common home alarm clocks use the powerline frequency to keep time. Most places use power at 60Hz but when I was in Japan, places north of Tokyo use 50Hz power. There was a switch on the back to set the frequency. Forgetting to change that switch would cause the clock to run fast/slow depending on where it was located. Perhaps yours has the same problem?
"Freedom in the USA is not the ability to do what you want. It is the ability to stop others from doing what THEY want"
I have been wearing a Seiko wristwatch for years now. It has a solar cell for a dial, and one day in bright daylight is more than enough for it to run all year (together it gets with the exposure from being worn daily). Right now, it still runs on the charge it got from me being in the Sonora desert, last summer. It is very accurate, with a deviation in the order of magnitude of a few seconds per year. When all those dumbos whipping out their cell phones when they want to know the time, I just flick my wrist. And with its large, white dial it just looks good.
Religous speak to God. Insane are spoken to by God. When all shut up, one can finally hear Shostakovich in peace
Sounds like an interesting Raspi or Embedded project. A mechanical NTP synced clock. I think I am going to try this.
The dangers of excessive individualism are nothing compared to the oppressiveness of excessive collectivism
For home use, who cares? Within +/- 5 minutes is more than good enough for everyday life.
For business use, the cost of a master/slave clock arrangement is peanuts if it actually matters (e.g. stock markets etc.).
For everything in between solutions will be expensive or homebrew.
There's a company in France and the UK: Bodet. They make their own GPS/radio controlled master clocks that can then send a signal over a licenced frequency across huge sites (30 acres+) to their client clocks.
They also have PoE based clocks and even speaker systems timed to the same signal. I promise you, they are not cheap.
Short of using a GPS module's output tied to some device displaying the time, that you make yourself, you're going to be hard-pushed to find a cheap system.
I speak as someone who runs two NTP pool servers, has all my gadgets at home and in work synchronised to GPS or NTP, and even has MSF-controlled clocks, watches and bedside alarm clocks (Daylight saving? Don't have to do a thing).
If you're out of the time signal range in your region, you're looking at GPS or NTP, and both require basically a computer somewhere (RPi or GPS modules on an Arduino, for example) doing the work, and a display of some kind (driving a traditional mechanical clock, or an LCD).
The replacement is mobile phones. I still have a radio controlled clock and rarely have issues with it. For a 3€ device it has survived a long time, and being Frabkfurt and CET based it has even handled changes to daylight savings time without any updates. That is pretty impressive, but if it died, my mobile phone would replace its function.
Hang a Kindle Fire with a clock dial app always on, up on your wall
Rome taught me patience and assiduous application to detail. Virtues which temper the boldness of great, general views.
Do you like DYI? Take a look here. http://www.instructables.com/i... It's for DCF77 (Germany Station) but surely it can be fitted for NIST.
San Jose Navigation's FV-M8 GPS module is available everywhere (including from Amazon) for less than $30. It has an NMEA output and a 1 PPS output for time synchronization. I haven't measured the time accuracy of this module, but the module it replaces had a measured time accuracy of better than 100 microseconds, the limit of the equipment I had to measure with.
This kind of thinking has killed the entire electronics industry, and is stifling innovation generally.
Why can't I buy an HD Radio/alarm clock for my bedside table? ("Nobody wants one, they use their 'smart' 'phones'," I'm told. So do you get up, open your eyes, so you can see the silly touch-screen to run things -- instead of having red LEDs (don't kill your night vision), a normal button for SNOOZE and a volume knob?) Why can't I replace my 10-year old DVR with another one that works with antenna broadcast? Same answer. Why do people use things like Instagram that don't even let you upload a picture from a normal PC? Same answer.
Lazy thinking like this is moving everything into the walled gardens of the megacompanies with oversight of the three-letter agencies, and sucking what little life remains in the do-it-yourself makerspace.
GPS clocks have lots of vulnerabilities and can be attacked easily. If you are in a stock exchange you to run rife is you spoofed a GPS signal. They also have limitations as to where they can be placed. The antenna length has limited reach and can't be too long either.
I have an idea for a PTP clock that I think would cost less than US$100 to make and would be unbeatable in terms of accuracy and security. The device would be placed on a PCIe board for ease of integration.
How's this from my home PFSense firewall? Seems my $60 MSI motherboard is pretty good at keeping time. -0.023ms offset after 512 seconds.
remote refid st t when poll reach delay offset jitter
==removed junk chars==
-ra.steadfastdns 216.86.146.46 2 u 388 512 377 14.234 -0.706 0.632
+rb.steadfastdns 216.86.146.46 2 u 144 512 377 14.356 -0.533 0.546
*dns1.steadfast. 216.86.146.46 2 u 400 512 377 14.826 -0.023 0.183
+time1.google.co 133.45.56.223 2 u 386 512 377 24.719 0.007 0.181
-time2.google.co 222.174.180.252 2 u 362 512 377 34.593 -3.214 0.550
-time3.google.co 63.32.115.164 2 u 354 512 377 38.754 -0.978 0.568
-time4.google.co 226.42.99.180 2 u 318 512 377 23.877 -0.292 0.398
My father worked in the new (and fancy) Lifeboat College in Poole, UK. Plagued by many design flaws (including direct line-of-sight from a corridor into a ladies cubicle via "architectural" windows), the steel beams that make up the structure partially blocks the timekeeping signal to the large deployment of time-syncing clocks. This makes for an amusing sight around noon, where all the clocks in the building would try to sync with the weak signal, and do many rotations round the clock face when the signal dropped out.
If you gave me a choice between a printer and a giraffe with explosive diarrhoea, i'll get my ladder and my raincoat
even without a sim card you should get wifi and use NTP.
This is the answer, though you may need a rooted phone and a third party app like ClockSync to make it happen (claimed accuracy '~1-20ms'):
https://play.google.com/store/...
seriously, or a kindle on sale. they are 40 or 50 bucks, have a 7" screen and can display photos, times, blah blah. the problem is hiding the power cable but *shrug* it could be worse
By and large, language is a tool for concealing the truth. -- George Carlin
I have had one of these for about 15 years. WWV, Solar and tough as nails. The newer ones even look better, I bought one for my dad that looks like a normal watch. Batteries last about 10 years if you wear short sleeves enough to charge them occasionally. Without a solar charge the battery lasts about 6 months. I have replaced the battery twice, they are about $20 and fairly easy to replace if you are handy and careful. Just watch out for the tiny springs.
Take it off the wall and throw it away. Use your cell phone or your watch for timekeeping. Problem solved.
Or perhaps a desktop computer? But, the clock predates him, so we don't know by how much, so if the wall it hangs on has gotten faded or dingy over time there may be a nasty shadow remaining when he takes the clock down. I would rather see the broken clock.
I am not your blowing wind, I am the lightning.
If you're in a penitentiary that doesn't allow phones inside for security reasons, that wall clock, or wristwatch, is a handy thing.
FTFY
I am not your blowing wind, I am the lightning.
From what I read from the OP, he wants a wall clock that keeps in sync. The first thing that comes to mind would be the Android tablets as posted above, as they can be synced via the cell network or NTP.
This might just be a niche market. Take an Arduino with Wi-Fi capability, add an inexpensive LCD touchscreen, add some code to handle timezones, manual time setting, and so on, and call it done. Toss in a FONA cellular antenna/modem whose sole purpose in life is to get the time from the cell network for accuracy, and that is another avenue of getting things working if Wi-Fi connections are not doable.
If you need accurate time, would a wall display clock really be the thing you are going for? I have an alarm clock and the sole reason I bought one was because I keep forgetting to change the summer/winter time and either come in too early or too late.
As nice as it is, I only look at the minutes and any other clock would be acutrate enough. moreover, since a few years I hardly use it as I have a phone with me that keeps the time. I also spend most of my time looking at a screen that has a time.
So as nice as it would be to have a cheap one that would be able to do what is requested, it is at most a nice-to-have not a must-have and if OP really thinks it is a must have, start selling one.
In all other cases: A standard clock wall is accurate enough. If precise time is needed, a clock wall will not be a good solution. Those who need a solution will already have one.
Don't fight for your country, if your country does not fight for you.
YMMV with the tablet. I own an Asus tablet that consistently loses a lot of time even though NTP is enabled. I know that NTP isn't blocked because unchecking the "Set time automatically" box and then rechecking it brings the thing into synchronization right away.
"Who controls the past controls the future. Who controls the present controls the past." -- George Orwell
Before before home internet made NTP possible, my £5 (US $7) kitchen analogue quartz wall clock from IKEA kept perfect time. Changed with the seasons, twice year as necessary, but it never needed correcting. It always felt ironic with all the other digital equipment (especially the pc) that this cheap and relatively unsophisticated AA battery-powered mechanism was superior.
Your wall clocks have zero drift? They are easy to get to without a ladder etc? Lucky you.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
Try getting a weight operated cuckoo clock. You have to adjust the pendulum up or down on the wooden stick to get the time rate close but it is never correct. If I can get it so it stays within a minute each day I am happy with it. So at least once a week you have to move the minute hand. And twice a day you have to pull the three weights back up to the top. Now talk about a lot of effort to keep time.
-- ssoorrrryy,, dduupplleexx sswwiittcchh oonn.. -Quote found on actual fortune cookie.
WWVB operates on a frequency of 60 kHz in the longwave band. Its primary purpose is to provide a digital radio signal for clock synchronization. Its sister stations WWV (in Colorado) and WWVH (in Hawaii) operate on 5, 10, 15 and 20 MHz in the shortwave band, and serve primarily as frequency standards, and to provide time and other information in audio format.
I am not a number - I am a free man!
<!DOCTYPE HTML>
// <!-- ;
// -->
<html>
<!--
Free "atomic" clock
Author: Matthew Mellon <Slashdot user 51228>
Copyright: This code is released to the public domain
Usage: Open this in a Web Browser. It will display a pretty darn close approximation to actual local time (adjusted for the difference in your CPU clock from reality). You could use this to turn an old phone into an "atomic clock" (emphasis on the quotes). The offset is re-checked hourly.
Notes: You might want to make this pretty using one of those new-fangled Cascading Style Sheets, or maybe you could display an SVG image of an analog clock and use a bit of scripting to update it. This step is left as an exercise to the reader.
-->
<head>
<title>Time</title>
<script>
var difference = 0;
var syncTimer
var updateTimer = setInterval(updateTime,13);
var req = new XMLHttpRequest();
function setTimers()
{
syncTimer = setInterval(sync,1000*60*60);
updateTimer = setInterval(updateTime,13);
}
function sync()
{
req.open("GET", "http://www.timeapi.org/utc/now", true);
req.onreadystatechange = function()
{
if (req.readyState == 4 && req.status == 200)
{
lastFetchedTime = Date.parse(req.responseText);
lastSystemTime = Date.now();
difference = lastFetchedTime - lastSystemTime;
echo(lastFetchedTime);
}
}
}
function updateTime()
{
ts = new Date();
ts.setMilliseconds(ts.getMilliseconds() + difference);
document.body.innerHTML = ts;
}
</script>
</head>
<body onload="setTimers(); sync(); updateTime();">
</body>
</html>
What I think some people don't know is that while the 60KHz WWVB signal penetrates most buildings very well, the antenna inside these clocks is a loopstick type, and is very directional; you have to know how it's oriented in the clock in question, and you need to know which direction Fort Collins is, so you can place the clock correctly. The Sangean atomic clock-radio I have in my bedroom even has the WWVB antenna in a separate housing on a cable, so you can orient it however you need to in order to get the signal. As stated above I have 4 of these type of clock (likely a 5th soon enough) from three different manufacturers, and all of them get synched at least 90% of the time. The worst that will happen is your clock will be off by a second or two until it's next scheduled sync, and if you can't tolerate that then I'd have to say you're expecting way too much of it.
Are YOU using the TOOL, or is the TOOL using YOU? Think about it!
Phones may not be accurate timekeepers if they are not connected to a network. But if they are connected to a cellular network they update their time regularly so they should do just fine. Smartphones also get time updates over WiFi, so they will stay accurate even without a cell contract. On some smartphones you can put the phone into airplane mode (which turns off all the radios) but then manually turn on WiFi; the cellular radio stays off if you do that.
Tablets will also serve nicely, even those cheap $30 Android tablets that are underpowered for most uses. Microcenter currently has a less-awful one for $35 new (though the display viewing angles are evidently poor), or you could use a $50 Fire tablet from Amazon, or somebody's old 2012 Nexus 7... you get the idea.
Take the wall clock down, disassemble it and remove the hands, then re-assemble and put it back up! Conversation!! 8-)
Except I would take pride in setting it each day from my wristwatch, so would not do that...
For almost a hundred years, many of the businesses and schools have wall clocks that set each day from a time pulse wire, that is wired thoughout the buildings. They were 60Hz electric and stayed pretty close over the day. At midnight the "master" clock would pulse the wire and all the others would jump to the midnight time. They just needed something to set the "master" clock to, in the main office. Some set it better than others.
You can get clocks, for a reasonable price, that stay within seconds for months or years. But it's not so easy to tell, when you buy it, just how accurate it will be.
The one we have was from a craft store, to make crafted clock faces and then just insert the mechanism. But I have seen others.
Maybe you just buy the cheapest clocks you can find? Not smart with anything... 8-)
My idea was to isolate the wireless network and only have it to do services such as NTP. You wouldn't have to configure the devices at all as they would automatically find the network and grab the time when needed. All you would need to do is click an option on your wireless router to turn it on. Not every device needs to be fully connected to the Internet. Timers to turn lights on and off, my stove, my microwave, and my alarm clock could all set themselves automatically with this but not suffer with the additional security holes of being fully on the Internet.
If you're in a facility that doesn't allow phones inside for security reasons, that wall clock, or wristwatch, is a handy thing.
Everyone has cell phones, but everyone also wants clocks. Humans!? What are you gonna do with them and their inconsistent ways until we're all replaced by robots (with their own built-in clocks)!?
A interesting idea but I just checked and it didn't.
As i said, for real world applications. Its a fucking wall clock in a house. Not a GPS sat. Oh and if you have ever done traditional navigation out at sea (i have), you would know that your never that accurate. Also a quartz movement is many times more accurate that a gimbaled mechanical chronometer. A temperature compensated quartz oscillator is down to parts per 100 million even a billion, cost a 100 bucks or so (i made some of my own GPS equipment in my masters). They don't give a shit about gravity and are far more robust. Get your anonymous coward head out of your shit hole, you have no idea what your talking about.
If information wants to be free, why does my internet connection cost so much?
sudo rdate -s time-b.nist.gov
Casteism
You can buy "radio controlled" clocks across the EU which rely on LF transmitters in Germany/UK/others.
These start at about $10 - https://en.wikipedia.org/wiki/...
WWVB operates a transmitter at 60kHz which is receivable across the lower 48 states. https://en.wikipedia.org/wiki/... and there are supposedly a large number of radio-controlled clocks available in the USA which utilise the signal.
There are known to be reception problems in the east coast of the USA (covered on the Wikipedia page) and NIST have attempted to (but been blocked from) setup an east coast transmitter. The NIST page advice should be noted. Modern houses with foil-lined insulation are effectively faraday cages at low frequencies and positioning of the clocks for best reception is important.
If you wish to improve the situation, mudge your congresscritter about it.