Casio G-Shock time sync radio

https://gshock.casio.com/intl/technology/radio/

by joos3 • 3 years ago

171 185 3 years ago

gshock.casio.com

Animats• 3 years ago

Great technology, works fine, at least 10-20 years old now.

_joel• 3 years ago

Time over radio has been a thing since 1927!

"A radio station at Rugby was first operated by the Post Office from 1926, with the call-sign GBR. From 19 December 1927, it broadcast a 15.8 kHz time signal from the Royal Observatory which could be received worldwide. It consisted of 306 pulses in the five minutes up to and including 10:00 and 18:00 GMT, with a longer pulse at the start of each minute. "

https://en.wikipedia.org/wiki/Time_from_NPL_(MSF)

ajhurliman2• 3 years ago

I have a wall clock that syncs with an atomic clock in Colorado, which was cool at first but I live in Arizona now which doesn’t observe daylight savings so it’s often wrong by an hour now.

johndavidback• 3 years ago

Yes but perhaps it reminds you of fond memories? Or just makes life a little more interesting - "Hey, dentist, sorry I'm an hour late!"

verandaguy• 3 years ago

Clearly the solution is to get Arizona to observe daylight savings!

ajhurliman2• 3 years ago

Or mount another hour hand on it that always tracks an hour ahead of the existing one with a label on which dates it’s applicable during. That’s a clean solution right?

bpye2• 3 years ago

All you need is a DIP switch or something on the back to let you set the offset.

ilyt13• 3 years ago

Just film it and display the video on monitor with 1h/23h delay, easy! /s

angled• 3 years ago

I have one of these in Hong Kong, which due to the mountains, doesn't get the China radio signal that reliably.

https://www.amazon.co.jp/-/en/Seiko-GP219W-Office-Satellite-...

Looks great, has a quiet sweeping hand, handles DST automatically provided you set the timezone correctly.

Grazester• 3 years ago

I have a citizen watch with this. Tends to keep time just fine. Though so did all my other quartz watches until the battery dies

ricc5• 3 years ago

Radio syncing is perfect for those who require accuracy down to the second.

huhtenberg2• 3 years ago

Quartzs don't auto-adjust to DST. A minor nit, but annoying.

tcmb2• 3 years ago

They misspelled Mainflingen, where the German DCF77 transmitter is located, as "Mineflingen", which is basically spelled phonetically (for English speakers).

rwmj4• 3 years ago

The website probably had a round trip through katakana which would explain phonetic spellings.

tcmb2• 3 years ago

Cool to have this multiband technology, but what about the southern hemisphere? Assuming they have time signal transmitters, too: Do watch manufacturers have different SKUs that can receive signals in the southern hemisphere? Is it possible to have a watch that receives these signals truly worldwide?

psychphysic5• 3 years ago

These days you'd probably use GPS/GLONASS etc.

firewolf34• 3 years ago

Yes, as others have stated this is an old technology. I don't really understand why this is not more common in the modern day. it's not really that expensive to implement and they did it with analog chips back in the day...

Why do we have to set the time on our clock radios or on our microwaves or whatever? Why don't they just always use this Tech. I don't understand. All you have to do is allow people to store an offset for the time zone, and RTC issues are a thing of the past.

psychphysic5• 3 years ago

It's easy enough to implement decoding and there are packaged antenna (ferrite rod and coil) and conditioner (auto gain amplifier with Schmitt trigger output).

V__• 3 years ago

Is it really not common? I don't thing I have seen a digital clock or modern wall clock which doesn't have it. I think my Microwave has it too. Onky my oven doesn't. Is it maybe more common in Europe?

freetime2• 3 years ago

I use a Phillips Smart Sleep alarm clock that doesn’t support this, despite being pretty expensive at around $100. I’m not even sure if the higher end model which costs twice as much and claims to be “connected” supports this feature.

pjerem• 3 years ago

I’m also in Europe (France) and during my entire life I never owned a single appliance with automatic time configuration (except for anything iot of course).

I have seen this automatic radio thing once in a very old alarm clock owned by my grandfather but that was probably in the end of the 90s.

layer83• 3 years ago

It’s common in clocks, but not in other appliances (nor in cars).

nonethewiser• 3 years ago

And daylight savings?

chriscjcj• 3 years ago

The time code transmitted by WWVB includes two bits to express the state of Daylight Saving Time.

  0 = Standard Time
  1 = DST Ending
  2 = DST in effect
  3 = DST Beginning

https://en.wikipedia.org/wiki/WWVB#/media/File:WWVB_time_cod...

https://en.wikipedia.org/wiki/WWVB

ricc5• 3 years ago

Radio syncing is perfect for forgetting about setting clocks for DST on/off because the sync automatically does that for you.

graypegg5• 3 years ago

It does feel like something that’s easy to cut from a bill of materials though, nothing else in the microwave relies on the time being accurate.

Probably not expensive to implement, but if you’re building a lot of them, I imagine the ~4cents per unit (maybe more, just guessing) adds up fast.

bpye2• 3 years ago

Whilst it maybe doesn’t need to be accurate, I have had an oven that wouldn’t turn on if you didn’t set the time…

bayindirh6• 3 years ago

My professor is a materials/mechanical engineer and in contact with many auto companies. He told me of the following dialogue:

    Prof: Why did you stopped adding passenger side handles? How much one cost?
    CarGuy: Around €1.50
    Prof: That's not much?
    CarGuy: A new car leaves the factory every 60 seconds.
    Prof: Oh.

For the lazy, that's €2,160/Day, €64,800/Month, €777,600/year.

lm28469• 3 years ago

nothing else in the microwave relies on the time being accurate.

The real question is why does your microwave gives time in the first place. Sounds like they had a display and didn't know what to show on it while the microwave wasn't actively used, I'd say drop the clock altogether

RealityVoid• 3 years ago

I would gladly pay 4 cents more just to never have to figure out how to set the time on my oven or microwave ever again.

ilyt13• 3 years ago

Probably more.

And they are too cheap to even put a capacitor in to cover for most short power failures

gm3dmo2• 3 years ago

There is already a time signal in the electrical grid:

https://www.meinbergglobal.com/english/info/time-synchroniza...

Why don't they just always use this Tech. I don't understand.

The bit's that get your oven to work don't need the time. Adding the bits for this is a cost and a thing that can fail because it can't receive the radio signal that equals a Dead on Arrival for your oven and a service call at least. When it's on a watch it's likely near your wrist which is likely near a window which likely means it can get the radio signal to sync.

toomuchtodo2• 3 years ago

Your citation is about using GPS as reference for electrical grid operations/control purposes (very common if your use case can rely on GPS versus local high precision time sources such as a cesium clock). If you were referring to using electrical grid frequency for time keeping, that is a suboptimal solution due to frequency stability nuance.

https://www.dhs.gov/sites/default/files/publications/GPS-PNT...

https://phys.org/news/2011-06-power-grid-disrupt-clocks.html

https://medium.com/@bramus/grid-time-or-why-are-clocks-in-eu...

https://www.entsoe.eu/news/2018/03/06/press-release-continui...

https://www.nist.gov/publications/time-and-frequency-electri... ("Due to the efforts of Henry Warren, inventor of the Telechron electric clock, electric power companies have been a source of time and frequency reference for the public for over a hundred years. However, advances in technology and changes in the electric power industry have generated a movement within the industry to end the time-reference service.")

Aloha• 3 years ago

As mentioned by a parallel commenter, your link doesnt say what you think it does.

That said, the most power line synchronization is useful for is clocking not time, and to be very honest, its only a consistent clocking source in some places (who perform adjustment to ensure a long term value of 50/60 Hz), which means it can be used to provide a clock source to keep a device in sync, which already knows the time, but cant be used for cold start of a device.

_trampeltier• 3 years ago

Usually yes, the frequency in the electric grid is pretty stable but ..

.. it's not really precise 50Hz, just +/- 50Hz.

.. there are more than just proof of concepts, you can tell from a video, when it was made from the backround noise from the main grid.

https://www.umiacs.umd.edu/publications/seeing-enf-natural-t...

.. a few years ago, was the European electric network several minutes to late, because not every country did pay for the electric power.

https://www.nationalgeographic.com/science/article/european-...

clusmore• 3 years ago

Note that an integer offset is insufficient. For example, Australian Central Standard time is +9:30 and Australian Central Western Standard Time is +8:45. I have a Seiko watch with a similar feature to this and I don't think it would work well in either of these timezones.

ilyt13• 3 years ago

You can just change timezone on watch and it keeps offset. But yeah, mine has like... one that isn't multiple of 30 minutes

pkulak• 3 years ago

That’s not even enough because different zones observe DST at different times, or not at all. You would have to enter your actual time zone, not an offset, like when you install an OS or something. And then if that zone ever changes, which happens a lot, the clock in your microwave will often, or always, be wrong. So now your microwave needs to be internet connected to download tz databases, and what are we even doing here.

ilyt13• 3 years ago

Have you...used them ?

My Protrek basically doesn't sync if I'm at home, and as it tries to start sync after midnight the auto sync near-never works. I installed DCF77-emulator app on phone to get around it.

My radio-synced clock works fine but comes with big (BIC lighter size but double the thickness) external antenna.

Probably much worse in microwave that's somewhere inside the house and not near window

All you have to do is allow people to store an offset for the time zone, and RTC issues are a thing of the past.

Just to clarify, we're talking about people who couldn't bother to put $0.2 capacitor to hold the RTC battery for the few hours the power is usually down, and you're expecting them to put whole antenna and radio in ?

Yeah, it isn't feature anybody will choose white goods for so it isn't in.

gh02t• 3 years ago

Damn I had never thought of the possibility that you could easily battery back the clock in a microwave/oven/etc despite being fully aware that it's trivial to do. We get a ton of brownouts and I gave up on keeping the clocks set. I want it.

basking2• 3 years ago

My dad loves his. I bought a new one for him after 15 years of use. Both watches were the correct time. He swims a lot in it, and the old one is much smoother than the new one. I love that guy.

layer83• 3 years ago

I have a number of DCF77 clocks in my home, including small alarm clocks. No external antennas. No issues whatsoever.

basking2• 3 years ago

My dad has a g-shock that lasted 15 years. He loves it. Model: MTG-M900DA-8CR. I bought him a new one a month ago, snd he almost cried because he was looking for this watch in garage sales. He asked me to set it, we looked and both watches were already set to the correct time down to the second. The face has a solar panel that you can’t see.

tysam_and2• 3 years ago

Oh....my gosh. That's the exact one I had growing up as a kid for years. Wow. The memories are flooding back now. Wowie. I faithfully charged it in the sun whenever I saw it run low, and one night woke up maybe somewhere between 1 and 3 A.M. to see it syncing. I was maybe, oh a little older than 7-8 at the time.

I felt so overwhelmed with excitement that I ran over and woke my sister up to tell her my watch was syncing with the atomic clock in New York. She did not nearly share my level of enthusiasm over the subject matter at hand.

Of all of the more stereotypically autism-related memories I have of little me, that one is one of my favorites. My passion and excitement at the time was so cute. :') <3

Ekaros4• 3 years ago

Just looking at those maps should explain part of it. There isn't enough coverage. So you end up with poor experience with substantial amount of people who do not get good signal.

This would likely result in lot of returns, warranty claims and so on. Just not worth it in general.

Gud2• 3 years ago

I have a 15+ years old G-Shock with this feature. When I was in Afghanistan in 2010, I would still occasionally get this signal. I suspect these coverage maps are quite conservative.

noAnswer2• 3 years ago

So you end up with poor experience

...as opposed to what? How is a blinking 12:00 a better experience?

mmcgaha• 3 years ago

It isn't more common because most folks don't need it it. I touch my digital watches twice per year and that is more than enough to keep them close enough. Of my two digital watches, one is 1 minute fast and the other is 45 seconds fast. They will both be fine until this fall when we change time again.

cbzoiav2• 3 years ago

The only thing I can think of is if it was widespread it would be a security risk. Not exactly difficult to broadcast a stronger signal with the wrong time.

Similar problem with GPS being used for clock sync in mobile/cell base stations in much of the US. You can buy an (illegal) jammer off Ali express and bring down a tower for very little money.

agos2• 3 years ago

I don't know where you live, but here broadcasting such a signal would mean having the police knocking at your door really quickly. Unauthorized broadcasts are taken very seriously

vbezhenar• 3 years ago

Probably because it's supported only in a few countries.

paulmd4• 3 years ago

another fun "we had a better solution in the past!" is using the 60hz AC sine wave as a time signal. The timebase is actually corrected for this use-case! there is absolutely no reason to use a piezo timer in any circuit that is plugged in to AC and the drift that typically occurs with piezos is so frustrating.

https://en.wikipedia.org/wiki/Utility_frequency#Time_error_c...

lr1970• 3 years ago

Why do we have to set the time on our clock radios or on our microwaves or whatever? Why don't they just always use this Tech.

The main reason is lack of reliability or better to say strong dependency of reception success from location of the receiver. My G-shock watch never synchronizes when in kitchen but gets sufficiently strong signal in the bedroom. Wrist watches are more mobile and have better chance to be in a good signal reception spot at least once in a while. A microwave, on another hand, is stationary and if out of luck (weak signal) that it is permanent. Not a good solution for time sync (and possibly complains from dissatisfied customers).

psychphysic5• 3 years ago

If you're interested in buying a Casio watch that does this they tend to be called Waveceptor, I'd recommend looking at one that's also solar powered (tough solar).

rwmj4• 3 years ago

Oceanus S100 is absolutely brilliant. Solar powered, radio time sync, titanium (so incredibly lightweight), waterproof, and looks like a dress watch. The only downside is they are only sold in Japan so you have to import them.

mewse-hn• 3 years ago

There's a Lineage LCW-M100TSE that should be a bit cheaper - titanium, sapphire crystal, radio sync. Also JDM though.

ekam• 3 years ago

The T200 is a great option too- you sacrifice the titanium for stainless steel but get more flexibility as the strap is removable (which IMO makes it more versatile). Beautiful dial too. I own one and I've been looking for watches with similar tinted crystal but haven't been able to find any that do it nearly as well.

symlinkk• 3 years ago

42mm is huge though

ricc5• 3 years ago

Or a G-Shock which uses the keyword "Multiband 6".

psychphysic5• 3 years ago

The only downside the G-shocks last forever and you'll never need another watch :)

ilyt13• 3 years ago

Also show up in other series, Protreks have it for example. Althought mine is not great indoors and even outdoors needs a bit of finangling to start the sync

somat2• 3 years ago

I specifically went with a battery model because I was not convinced that the battery in the solar models would actually last that much longer than the battery only model. While you can replace the battery in the solar models it is a proprietary part and considered watchmaker level service, while with the battery model it is normal service with a generic part. So I decided that replacing a battery every 5 years would not actually be that bad compared to trying to find a proprietary part every 10 years(A guess based on forum posts, so worthless).

All of which is a false economy. As I buy what is actually a cheap mass production watch as if it were some sort of heirloom piece that I will be passing down to my grand children. Anyhow, whats the point of being a geek if you can't overthink things sometimes?

psychphysic5• 3 years ago

I've replaced the lithium rechargeable in my Gshock once. It was quite easy I have to say but the buttons are fiddly.

I got the battery off eBay for about £16.

Straps are what give out first and I've been through about 4 where it's become unsightly or otherwise degraded.

itisit• 3 years ago

I'd be curious to see a proper signal map for this service. I've been the proud owner of a Casio Oceanus for a little over a year now. I can count on one hand the number of times the watch has synchronized via radio.

ricc5• 3 years ago

Yeah, the signal for this is rather weak so you would need to place your watch at least on a window's line of sight or, if it still doesn't work, right next to a window.

tjohns• 3 years ago

Here you go: https://tf.nist.gov/stations/wwvbcoverage.htm

Keep in mind antenna placement matters with these clocks. Different parts of the room can have very different signal strengths. Away from other electronics and near a window is all better.

joeig• 3 years ago

Back in school, we learned how basic binary protocols work using DCF77 as an example. We decoded it on a piece of paper. Good old times.

toomuchtodo2• 3 years ago

Related thread with local transmitters of time signal: https://news.ycombinator.com/item?id=27769403

https://github.com/hzeller/txtempus (A DCF77, WWVB, JJY and MSF clock LF-band signal transmitter using the Raspberry Pi)

ios and mac app: https://forum.audiob.us/discussion/49109/pips-a-radio-time-s...

(time sync over rf is super cool; I would be super interested if anyone has links to field surveys of time signal availability, potential gaps in coverage, and maps of said data.

gregsadetsky2• 3 years ago

Thanks for those references! I wanted to see what an SDR radio time signal detector would look like, and looking for "DCF77 sdr python" pointed me in the right direction -> [0] and [1]

A bit unrelated question: there are many web SDRs that let you listen to radio frequencies/stations such as [2]. Are there web / Emscripten SDR decoders that run in-browser? i.e. a full browser listening + decoding experience? For example, decoding a DCF77 time signal, or even just morse code?

[0] https://www.nist.gov/time-distribution/radio-station-wwv/wwv...

[1] https://github.com/henningM1r/gr_DCF77_Receiver/tree/main/py...

[2] http://websdr.ewi.utwente.nl:8901/

madengr• 3 years ago

This is mine. Select the timecode decoder:

http://kiwisdr.lounix.net:8073/

jowood• 3 years ago

Android app https://play.google.com/store/apps/details?id=jp.houryo.dcf7...

ggm• 3 years ago

I run this for my Citizen Skymaster on a picoPi. It works. Being within receiving distance of JJY in Yokohama IETF, and in Frankfurt near the german transmitter was wonderful, but I have an NTP synced dummy at home with a copper loop antenna and it works fine.

Using the HDMI lead interferes with the rPi GPIO signal being used to supermodulate the RF. As long as you don't drive the HDMI, its fine. I think its possible HDMI is an RF radiator.

The java/javascript trick with headphones works too.

1MachineElf• 3 years ago

I inherited one of these Casio Waveceptor watches from my father.

It routinely will set itself to a totally random time far into the past/future. I've wondered if maybe contemporary wireless devices interfere with the time sync radio. Another possible factor is the watch itself is ~20 years old.

ricc5• 3 years ago

Maybe it just needs a battery replacement?

tomduncalf• 3 years ago

Maybe Casio are using a Windows server heh (https://news.ycombinator.com/item?id=37151220)

ilyt13• 3 years ago

I also remember their NTP server being near-continously unreliable and having to change the ntp sync server on every install. I wonder if that's still an issue

creeble2• 3 years ago

It's not totally uncommon. I have a Waveceptor and several other clocks that use WWVB.

One works perfectly, most of the others are usually good, one gets off a couple of times a year (so therefore useless), and my Waveceptor has gone nuts maybe a couple of times.

It seems to be all about signal strength (and a little bit about battery strength).

I see at least one of those watches has GPS reception.

gxqoz• 3 years ago

I've used a series of them for over 20 years and never had this issue.

jiehong• 3 years ago

Got a Pro-Trek PRW-30, and this works flawlessly.

It syncs almost every night, and takes into account DST just fine.

topynate• 3 years ago

I spend most of the time out of range, but the technology is simple and robust enough that you can use headphones or a phone speaker as a very, very short-range transmitter. You hardly need to sync every day, either. I've had most success with https://einoko.github.io/DCF77.js/

tamimio2• 3 years ago

That’s very cool tool, thanks for sharing that

TrianguloY• 3 years ago

I have an alarm clock with this system (or I think it's this, it's from Oregon Scientific) and it has this "automatic clock sync" feature.

I have it disabled. Once it was set to a random time, and I lost an important meeting because the alarm didn't ring at the correct time. The usual time doesn't deviate more than a second or so every few years, when I need to change the batteries and set it again so it's useless.

This automatic feature would be perfect if it acted as a "press this button to setup" or at startup, but the issue is that the messages are sent very sporadically so you either need to wait almost a full day for it to sync (clocks are not always listening, so it needs to coincide the "push" and the "listen") or set it manually.

noAnswer2• 3 years ago

This automatic feature would be perfect if it acted as a "press this button to setup"

You press the receive button on the Casio.

but the issue is that the messages are sent very sporadically so you either need to wait almost a full day for it to sync

The signal is constant. You probably had bad reception. In case of DCF77 it needs one minute to transmit "date + time + parity". I have seen my G-Shock syncing in under two minutes.

gm3dmo2• 3 years ago

Casio are the best watches I've ever owned. Radio sync on a watch is awesome for creating "drop the mic" moments showing how far out the clocks are on a multi-million dollar machine in a datacenter despite how much the big consultancy thinks they are synced to UTP via "atomic clocks".

vlachen3• 3 years ago

I wore a G-Shock Wavecepter while serving in the U.S. Marine Corps. I recall that on both of my shipboard deployments (2004 and 2006) I was very excited to have my watch set time automatically. It indicated that I was finally nearing the U.S. East Coast. It helped to be an aircraft mechanic on night crew, as I was usually on the flight deck when it tried to set time.

deltarholamda• 3 years ago

It indicated that I was finally nearing the U.S. East Coast.

There is a plot device for a Tom Clancy novel in this little factoid.

strangattractor2• 3 years ago

Have solar atomic version. Don't wear it much these days. Mostly when I travel. Been on my dresser 2 years collecting dust but gets some sun. Picked it up the other day for a camping trip. It was both charged and had the correct date and time.

vlachen3• 3 years ago

My battery has given up the ghost, and it's probably in a box of stuff around here. At the time, putting a new rechargable in it was impossible. I wonder if that's changed now... Edit: Neglected to mention mine was also solar

jansan• 3 years ago

The newer ones go into sleep mode until they sense some movement. Each morning when I pick up my GW-M5610U-1 (of course with the titanium mod), the display is blank and then fills with data within a second or so. I really like the feeling that although I hopefully have a few more decades to live, this watch may be my trusted companion for the rest of my life.

p1mrx• 3 years ago

I wish Casio would bring back the WV-300 form factor: https://www.youtube.com/watch?v=t79GeZkTJLY

The closest modern replacement is the GMW-B5000, but that's quite large and expensive compared to what they were doing in 2008.

2-718-281-828• 3 years ago

not working in SEA, though :/ there are some tricks with apps synthesizing a electromagnetic radio signal via speaker activity but i never got this to work.

ilyt13• 3 years ago

I used "DCF77 Emulator" on android and had to get it very close to the phone's speaker to work

markdoubleyou• 3 years ago

My Pro-Trek syncs most nights in Seattle, but only if I leave it on a window sill with 12 o'clock facing southeast.

jcul• 3 years ago

Good read on the accuracy of radio controlled clocks: https://tf.nist.gov/general/pdf/2429.pdf

nabla92• 3 years ago

I have Casio GW-M5600. It's a perfect watch.

- Looks like classic G-Shock.

- shows correct time always (time sync)

- never runs out of battery (solar charging).

ilyt13• 3 years ago

Same with my pro-trek, aside from not working all that great indoors for sync.

Apparently Garmin have some Smartwatch that actually got low enough to also be pretty much constantly on Solar only power but after owning original Pebble I kinda healed myself from smartwatch hype before the fashion for them even started...

dingaling• 3 years ago

I have Casio GW-M5600. It's a perfect watch.

It's very large, though. I haven't found a radio-set 'square' Casio in the Baby G-Shock range which would be a better size.

nabla92• 3 years ago

No it's not. It's the size and look of classic small Casio.

I bought it maybe 10 years ago. I think it's "origin" series or something like that. They still sell them in ebay for ~$100.

friend_and_foe2• 3 years ago

I'm curious why we don't just use GPS's UTC time broadcast to set time? I understand that using GPS to track satellites and find location is power hungry, but I can't imagine that simply receiving a time and setting a clock is any more power hungry than this system.

JCM9• 3 years ago

GPS signals are much higher frequency and very low power and thus don’t work indoors. These HF time signals are way more powerful and can be detected inside buildings.

iszomer2• 3 years ago

In the interest of the previous reply, Casio's GBD-H1000 has the ability to time sync with GPS.

tw19842• 3 years ago

GPS signals are much higher frequency and very low power and thus don’t work indoors.

With a $20 antenna placed near the window, together with a modern receiver, it is easy to get nanosecond level of precision for GPS systems. Some receivers even have in-door precision specification.

GPS not only work indoors, in terms of timing, it works actually pretty well indoors.

Qqqwxs2• 3 years ago

GPS determines a solution for position and time simultaneously. It requires 4 satellites to solve for 4 unknowns (X, Y, Z, t). If you know your position you can solve for time using only 1 satellite, but a watch is always moving so it's position won't be known.

defrost• 3 years ago

You might want to rethink that.

There's no need to 'solve' for time - it's included in the raw data packet from any single satellite.

As any 'solution' carries an inherent error margin, the desire for an excess of sats doesn't stem from solving for time but the reduction of error.

paulmd4• 3 years ago

you understand the reason, GPS units are expensive and take a lot of power ;)

the GPS module itself is probably bigger than most of these watches, and the module itself probably costs more than most of the watches too! (probably something like $100). even if you can power it, which, the power consumed is probably 3-4 orders of magnitude more than the watch.

on the other hand, you have a point about receiving a signal and setting the clock, and I wonder if you couldn't parasitically drive this off the cell network... is there a local reference clock signal in the cell system that you could pull timestamps from and set the clock? cell signals are much much stronger than GPS and don't require constantly tracking satellites to maintain a fix. and while you still need some RF components (as does this casio watch, it's still acting as a RF demodulator!) they can presumably be much simpler and cheaper and lower-power.

(edit: actually I see some people here commenting some watches apparently do exactly this, so your "use the time reference from a single satellite and accept the skew from lightspeed" idea probably does work, although it's a smartwatch and runs its battery quickly.)

really I think most people do not even need continuous updates though. This is something you could build into a "charge cradle" for the watch and have the time reference sent via a data carrier on the inductive charge signal. which does open GPS sync back up a little bit (although wifi/bluetooth would be cheaper and just as good for most people) since the GPS can live in the cradle too.

people are talking about solar watches etc and to be honest if you've got 1-2 years of battery life who cares about solar? Pop it on the charge cradle once a year and charge it inductively. Inductive charging might actually be simpler/cheaper than even those micro solar panels watches and calculators use, and everyone has gotten into the habit of charging their smart watches overnight anyway. And if you do that, it allows you to do the cosmetics of the watch however you want, since you're not tied to having a big solar panel in part of it.

tamimio2• 3 years ago

Either get Gshock GWM5610-1 which is solar and synced for good price, or get Garmin Instict Solar for all bells and whistles and also unlimited power in theory.

DeathMetal3000• 3 years ago

I have the all black GW-2310FB. I’ll be honest, the gray digits on black background can be a little impractical in low light (it does have a very good backlit if you press the button). But it looks awesome and I have no regrets. Love it. And for those of you that are militant about your IDE’s dark mode, this could be the watch for you too. https://www.casio.com/us/watches/gshock/product.GW-2310FB-1/

IamTC• 3 years ago

Had the GW9400. Now using GWG2000

Works flawless in Seoul and Beijing. A month in South Bay and flawless too.

There is no signal for this back home in Singapore. What I do - since we also don't know when they're gonna shut off the radio towers - is use an app on my Tab S8 Ultra, set my watch's time zone to Tokyo, leave watch right next to speaker and go do something else. After some beeps and minutes : my watch time is readjusted.

No fiddling.

wsc981• 3 years ago

I just wish this time sync feature wasn’t limited to only Western world and East Asia.

A nice feature, but not usable in Thailand, where I live.

BHSPitMonkey2• 3 years ago

Another comment[1] describes a simple way to sync these devices just by playing a sound from a device with a browser.

I also think most (all?) timepieces with a GPS antenna will sync with good enough precision when you have line of sight to the sky.

globular-toast• 3 years ago

I've been using a radio controlled clock for many years. At some point I noticed it was more frequently reporting it had been unable to sync properly. I'd never noticed this before. Turned out the UK time signal had moved from Rugby to Anthorn. It really seemed to negatively impact reception.

veave• 3 years ago

I have one in the south of Spain and it doesn't work practically anywhere and definitely not where I sleep (since it can be set to synchronise after midnight automatically)

I bought it in part because of this feature and it was quite sad. These quartz watches are good but they still drift substantially after a few months.

Thankfully I heard of the DCF77 emulator app thanks to this thread and I will use it.

saagarjha• 3 years ago

I had one of these when I was a child. I now have an Apple Watch on my wrist, go figure.

spookie2• 3 years ago

For anyone in the Iberian peninsula, I've had some luck using UK's radio on mine. Be mindful to try it at night, and if the meteorological conditions allow.

Hope there were more stations...

maratc• 3 years ago

That was (and still is) a great technology, but in the last couple of years Casio has bluetooth-enabled watches that can sync with your phone (that is syncing with the base station, which syncs with GPS). Bluetooth adds about $10-20 on top, but works indoors and outdoors, day or night or on-demand, all around the world.

(The usual Casio G-Shock time deviation is under 20 seconds per month, so there's that.)

tempodox• 3 years ago

My $0.02: Junghans solar radio watch. Analog display, smartphone app. Runs up to 21 months when fully fed. Never buy a battery again.

https://www.junghans.de/en/collection/watches/junghans-radio...

hammeiam• 3 years ago

Your $0.02 costs $1500

19h• 3 years ago

I’m from Germany — we drove to Arizona from California a few years ago and were too late for check in which was super annoying. I got a SEIKO Astron watch that synchronizes the time via GPS after that and couldn’t be more satisfied; it also runs on solar and holds a charge of 6 months for when there’s no sun (i.e. Antarctica). This watch is so precise it’s my absolute time reference. When I’m traveling I keep my Apple Watch at home and only wear the SEIKO; the Apple Watch is pointless anyway if you’re stuck in the desert for more than a few days.

Casio G-Shock time sync radio

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