I wanted a clock that never needed setting. Things escalated(arstechnica.com)
arstechnica.com
I wanted a clock that never needed setting. Things escalated
https://arstechnica.com/gadgets/2026/07/i-wanted-a-clock-that-never-needed-setting-things-escalated/
22 comments
I did went GPS+ntp route.
I have a few raspberry pis on my lan that serve NTP time. (you need more than one)
Over the years I've experimented with various flavors.
Right now I have a mix:
1) a pi3 with a gps hat and a battery backup for the pi itself. It uses ntp 127.127.20.20 for gps time, and 127.127.20.28 for PPS. The SMA antenna goes to receiver at the window
2) a pi3 with USB gps on a cable going to the window
3) a pi4 same as above, but with a tiny battery backup rtc attachment
4) a pi5 with usb gps + the new RTC with an added rechargable battery backup
usually, when power goes out, a few reboot, but #1 stays up if <1hr without power. If power outlasts the pi with battery backup, the RTC battery backups take over. strangely #1 doesn't reboot when it has power, some artifact of the battery backup hat - I have to manually reset it.
I've also kind of wondered if GPS might be able to give you a time less accurately but quicker. Sometimes I look at the NMEA GPS output, and it sometimes doesn't have a position fix, but it does give out a time + week number
(this is all for no good reason, just yak shaving.)
I have a few raspberry pis on my lan that serve NTP time. (you need more than one)
Over the years I've experimented with various flavors.
Right now I have a mix:
1) a pi3 with a gps hat and a battery backup for the pi itself. It uses ntp 127.127.20.20 for gps time, and 127.127.20.28 for PPS. The SMA antenna goes to receiver at the window
2) a pi3 with USB gps on a cable going to the window
3) a pi4 same as above, but with a tiny battery backup rtc attachment
4) a pi5 with usb gps + the new RTC with an added rechargable battery backup
usually, when power goes out, a few reboot, but #1 stays up if <1hr without power. If power outlasts the pi with battery backup, the RTC battery backups take over. strangely #1 doesn't reboot when it has power, some artifact of the battery backup hat - I have to manually reset it.
I've also kind of wondered if GPS might be able to give you a time less accurately but quicker. Sometimes I look at the NMEA GPS output, and it sometimes doesn't have a position fix, but it does give out a time + week number
(this is all for no good reason, just yak shaving.)
Floridian here. WWVB has never worked for me indoors (never tried outdoors). I've tried multiple vendors' clocks in multiple houses (wood frame and concrete). I assume the coverage is fine outdoors or with a sufficiently large antenna, but none of the clocks I've seen even have a mechanism to connect such an antenna. I could hack one, but then it would probably stop being cheap and reliable.
I'd love to buy an off-the-shelf WiFi+NTP clock, but everything I've seen is very expensive, intended for commercial timing applications or synchronizing clocks across a campus.
I'd love to buy an off-the-shelf WiFi+NTP clock, but everything I've seen is very expensive, intended for commercial timing applications or synchronizing clocks across a campus.
I was going to mention an Atomic Clock. I use one in an RV and it sets itself even outside of cell phone range. I know it uses a radio signal of some type but I have no idea how it works. It rights itself within a few minutes of time changes, battery loss, or the like.
It's fascinating reading if you're interested in finding out the details: https://en.wikipedia.org/wiki/WWV_(radio_station)
We’ve come full circle.
https://news.ycombinator.com/item?id=46952384
https://github.com/tanvach/clocksync
https://github.com/kangtastic/timestation
https://github.com/hzeller/txtempus
WVB: A Tiny WWVB Station - https://news.ycombinator.com/item?id=13258631 - December 2016 (49 comments)
https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
https://news.ycombinator.com/item?id=46952384
https://github.com/tanvach/clocksync
https://github.com/kangtastic/timestation
https://github.com/hzeller/txtempus
WVB: A Tiny WWVB Station - https://news.ycombinator.com/item?id=13258631 - December 2016 (49 comments)
https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
It's a clock. Does it really have to have remote updating, a command line interface, an Internet connection, and HomeKit integration? That's too IoT.
I have three La Crosse clocks that run off the NIST time signal out of Boulder, CO, and need their AA battery replaced maybe once a year. The real challenge is running such a thing on a small battery for a year.
I once made a small clock that displayed "A LITTLE AFTER SIX" and such, changing its text every five minutes. Needed a power connection, though.
I have three La Crosse clocks that run off the NIST time signal out of Boulder, CO, and need their AA battery replaced maybe once a year. The real challenge is running such a thing on a small battery for a year.
I once made a small clock that displayed "A LITTLE AFTER SIX" and such, changing its text every five minutes. Needed a power connection, though.
I'm close to DIYing it also. I have two of the la crosse clocks. One works well. The other consistently fails to update. It would be cheaper to buy a new one to see if it's a dud or that location, but I already gave up on it and modified it to have a programmable LED strip integrated into it to visually indicate to my son when it was ok to get up for the day (before he could read a clock).
So, ironically, I've ended up with a non-automatic atomic clock that instead contains a raspberry pi pico w that speaks ntp and has a programmable LED strip. That I have to manually set every DST transition, although the LED controller handles it just fine.
So, ironically, I've ended up with a non-automatic atomic clock that instead contains a raspberry pi pico w that speaks ntp and has a programmable LED strip. That I have to manually set every DST transition, although the LED controller handles it just fine.
I'm with you. I like the DIY, take-things-into-own-hands drive and exploration. I think the next iteration would be nice as a back-to-basics learning journey, to see how less can be more, and explore the possible tools. (e.g. likely settling on a more elegant setup as you imply)
I feel like if you were gonna overthink this, you could’ve done something really cute and clever.
Like an AI that stares at the window and figures out which angle the sun is coming in, then makes a determination on what time it must be.
Then while it’s not sunny or can’t figure it out, it has dead reckoning, but it’s constantly looking at angles of shadows that determine if the time has drifted.
Like an AI that stares at the window and figures out which angle the sun is coming in, then makes a determination on what time it must be.
Then while it’s not sunny or can’t figure it out, it has dead reckoning, but it’s constantly looking at angles of shadows that determine if the time has drifted.
It would just start counting
"One, the path not taken, started with an Arduino or Arduino-like microcontroller. The other began with a Raspberry Pi or Pi-like computer-y thing. I went with the Pi, variously using both a Raspberry Pi Zero W and Zero 2 W."
Ok, so instead of bumping your clock +- one hour twice a year you preferred distro upgrades?
Ok, so instead of bumping your clock +- one hour twice a year you preferred distro upgrades?
This reminded of this other clock project:
https://mitxela.com/projects/precision_clock_mk_iv
Also: I reckon the closest best-value watch alternative that ticks most(?) of the author's boxes is the Casio GW-M5610-1ER, so long as you are inside a radio-controlled time area.
Also: I reckon the closest best-value watch alternative that ticks most(?) of the author's boxes is the Casio GW-M5610-1ER, so long as you are inside a radio-controlled time area.
Casio also has cheaper "wave ceptor" models that do this. If you get one from Japan you can get a nice-looking rectangular model.
I feel this article's premise too much. That's exactly the sort of clock I wanted to get my mom as a gift.
Why is it so dang impossible to find a not trash simple LED clock that's 'large print', 'the right color', and not annoyingly too bright?
A deluxe model might include a day of the week bar or dot and a month / day in month number (smaller than the time, mostly people care about the time)
Why is it so dang impossible to find a not trash simple LED clock that's 'large print', 'the right color', and not annoyingly too bright?
A deluxe model might include a day of the week bar or dot and a month / day in month number (smaller than the time, mostly people care about the time)
My parents rely on mechanical clocks, adjusting and ‘winding’ weights almost every day, they take great joy and pride from the fiddling. It’s fun to hear the clocks announce the hour and slowly hear them drift over time.
I think too bright would be an issue with any LED display. Even lights on my modem in a different room are a bit much, I turn it off at night.
I've had the same struggle. There are some decent LED clocks with up to 1" displays (high), but any further and you get weird colors or glaringly-bright displays.
The best options are expensive clock displays from like Time Machines, MasterClock, etc... but they are not cheap and not meant for consumers.
The best options are expensive clock displays from like Time Machines, MasterClock, etc... but they are not cheap and not meant for consumers.
I knew if I scrolled through the comment section I'd find geerlingguy!
I found the following that works quite well
https://www.amazon.com/dp/B0CWKYRS84
(the LEDs come in different colors)
https://www.amazon.com/dp/B0CWKYRS84
(the LEDs come in different colors)
Did you look at memory clocks?
I just use one those awtrix clones made by ulanzi, multiple open source firmwares for it since esp32 based.
NTP, http api for displaying alerts, and mqtt support
No need for me to reinvent the wheel, works a treat mounted above my monitor
No need for me to reinvent the wheel, works a treat mounted above my monitor
Edit: I was wrong! original post below:
> Battery-backed self-setting “atomic” clocks that get their updates via the cosmic ether have been a thing for years and get me most of the way there, but damned if I could find one with a red seven-segment display that I liked (maybe someone else’s search kung-fu is better than mine?)
I found this with ~5 minutes of searching. I think it meets your critera: https://www.amazon.com/Sharp-Digital-Alarm-AccuSet-Automatic...
(Regardless, cool project! I think yours still looks better than this one)
> Battery-backed self-setting “atomic” clocks that get their updates via the cosmic ether have been a thing for years and get me most of the way there, but damned if I could find one with a red seven-segment display that I liked (maybe someone else’s search kung-fu is better than mine?)
I found this with ~5 minutes of searching. I think it meets your critera: https://www.amazon.com/Sharp-Digital-Alarm-AccuSet-Automatic...
(Regardless, cool project! I think yours still looks better than this one)
The clock you've linked is not an atomic clock. It has a pre-programmed clock with a battery keeping it going. If that battery dies, you still have to set the time manually.
Oh you're right! I was tricked by "AccuSet technology automatically sets the correct time when plugged in. No programming, no confusing buttons"
The author's primary lament is clocks that cannot withstand power flickers, yet every sub-$10 mains voltage clock from Walmart and Target that I've ever seen will take a 9V battery to make them resilient against such power interruptions.
Might want to flip the clock over and check for a battery door before starting next time.
Might want to flip the clock over and check for a battery door before starting next time.
LED segments may be nice, but why not go full out Nixie tube? There are several kits out there, but for the DIY ethic, you can add WWV sync - and even watch the synchronization process - with this fellow's project:
https://www.youtube.com/watch?v=smUwbzA9SEo
https://www.youtube.com/watch?v=smUwbzA9SEo
This really screams esp32/esphome, and as you'd expect, there are already dozens upon dozens of such projects https://github.com/mfactory-osaka/ESPTimeCast
The atomic time radio station WWVB does in fact broadcast a daylight saving time bit. A good atomic time clock should accurately update for DST (though Amazon reviews for a clock like this one is pretty mixed: https://www.amazon.com/Crosse-Technology-617-249-Curved-Atom...)
My La Crosse wall clock does support the DST bit, the switch on the back only sets whether you live somewhere that recognizes it or not. Twice a year I try and stay up to watch the clock hands zoomin around during the changeover
I've been using an old iPad as a clock for a while. The "Clocks" app I installed lets me configured 5 different alarms (quite handy since my week varies a lot).
I want a beautiful eink clock that gets its time from gps/gnss. It seems too much to have to collect a clock to wifi. Just turn it on and it should work.
Indoor GPS reception is spotty, especially in urban / high-rise environments, so I don't think that's a realistically marketable product. Not unless you some have some window- or balcony-mounted probe, which would then require battery changes (although I suppose you could make it solar-powered).
There already are clocks with GPS (but maybe not eink): try searching for seiko space link clocks eg https://www.sakurawatches.com/index.php?route=product/produc...
This is what I’m working on right now. It lasts about 3 months on battery updating every minute, except every five at night. I’ve been meaning to switch to a word clock to make it last longer.
Indoor signal reception problems though
There are lots of modern alarm clocks that pair via Bluetooth to your phone and auto-set the time from the phone’s time. No internet connection or NTP server needed.
But a smartphone's time is set how? Via the mobile network (NITZ) or NTP (SNTP)! And what protocol is going across the Bluetooth connection but SNTP? In NTP terms, your alarm clock is now in a stratum below the smartphone, and with only one source of truth, not a good situation.
Given that most alarm clocks only show hours and minutes, I'm not sure micro or nano second accuracy really matters. Provided my alarm clock is within a few minutes of the correct time I don't really care.
I meant the clock itself doesn’t need an internet or local network connection, with which it could do things other than syncing the time.
Then I think this is a trap to get some kind of proprietary app onto your phone.
The clock could set itself from radio signals: standards-compliant.
The clock could have WiFi or Ethernet and use [S]NTP: standards-compliant.
The clock could have a SIM and use NITZ: standards-compliant.
But BT it is. So now rather than having a dependency on standard or generic resources, it requires a BT pairing with the right kind of phone Ridiculous.
The clock could set itself from radio signals: standards-compliant.
The clock could have WiFi or Ethernet and use [S]NTP: standards-compliant.
The clock could have a SIM and use NITZ: standards-compliant.
But BT it is. So now rather than having a dependency on standard or generic resources, it requires a BT pairing with the right kind of phone Ridiculous.
There have been mass-produced don't-need-setting clocks for just under a hundred years now, the first Jaeger-LeCoultre Atmos clock, https://atmos-atelier.de/en/atmos-uhr/, being produced in 1928. You don't wind them up, you move a lever across to unlock them and then they keep running by themselves. The du Millénaire model won't need resetting until 3000AD, although perhaps that range may be a tiny bit optimistic.
How does it handle DST?
These aren't even self-setting, let alone self-adjusting. They are merely self-winding.
In fairness "merely self-winding" is quite the existential ambition for some.
* http://www.ocelotfactory.com/hoban/mouse.html
* http://www.ocelotfactory.com/hoban/mouse.html
+/- 1 minute for month? holy smokes. does not qualify as self setting.
Hooking that up to NTP would be quite a project.
What are you talking about, those will drift out of accuracy in a month
"setting the clock" means adjusting time, not powering
"setting the clock" means adjusting time, not powering
Wouldn’t it make more sense to build a GPS clock?
I can't decide how I feel about this article. On one hand, it's great. It's great that the author wanted to get something done, and thanks to the marvels of modern tech, they could do it with very little effort.
But on the other hand... gosh, this was about the simplest software engineering challenge imaginable (toggle some I/O pins) and the simplest design task imaginable (make a featureless rectangular box). And the author - a technologist! - isn't just saying "I wanted to try out some new tech". They're saying "this was too hard, I needed help from an LLM" ("would absolutely not be able to meet this challenge", "hit another wall").
And that... I mean, I just don't know what to make of this. Were we always like this? Are LLMs making us like this? Is it good? Is it bad?... and don't give me the calculator analogy...
But on the other hand... gosh, this was about the simplest software engineering challenge imaginable (toggle some I/O pins) and the simplest design task imaginable (make a featureless rectangular box). And the author - a technologist! - isn't just saying "I wanted to try out some new tech". They're saying "this was too hard, I needed help from an LLM" ("would absolutely not be able to meet this challenge", "hit another wall").
And that... I mean, I just don't know what to make of this. Were we always like this? Are LLMs making us like this? Is it good? Is it bad?... and don't give me the calculator analogy...
To be fair, I did the research, the BOM, the systemd service and timers, the packaging, most of the installer, and the deployment pipeline myself. It's just the python and the Fusion modeling I needed LLM help with. Coding beyond bash scripting is just not something I'm good at, and at 48, I've kind of accepted that it's not ever going to be no matter how hard I try.
Edit: retracted, but left up for context
The article itself appears to have had help from an LLM, too.
The article itself appears to have had help from an LLM, too.
Go look at the editorial policy from Ars. Lee just writes like that; it's his style, it always has been.
nope. i was using em-dashes and semicolons before they were cool.
I believe you (and sorry, I do think I was wrong), but for the record I wasn't judging based on punctuation.
If you think you need your alarm clock to be accurate down to the subsecond, you need to talk to someone about your anxiety.
I think a single clock-output-only microcontroller would be nifty. Something where you can save settings, such as NTP servers and an all time change dates, but that’s it. Pair it with PoE Ethernet and you wouldn’t even need a power supply, only an Ethernet jack in the wall. With the right display you could make it super thin.
POE clocks are SURPRISINGLY expensive.
https://www.american-time.com/shop/?fwp_product_brand=power-...
Someday, my precious, someday. (My dream clocks would have a smooth-sweeping second hand, no ticking (silent) and be PoE and NTP.)
https://www.american-time.com/shop/?fwp_product_brand=power-...
Someday, my precious, someday. (My dream clocks would have a smooth-sweeping second hand, no ticking (silent) and be PoE and NTP.)
All these other responders. Goodness. It’s a clock. It’s a fun little project they made *FOR FUN!*.
Did everyone forget that hackers and engineers like to have fun? Seriously.
Someone at Open Sauce this year made a friggin CRT-based VR headset. Why? Why not.
Did we forget where we came from? Does everything have to be optimal?
Did everyone forget that hackers and engineers like to have fun? Seriously.
Someone at Open Sauce this year made a friggin CRT-based VR headset. Why? Why not.
Did we forget where we came from? Does everything have to be optimal?
>"...but damned if I could find one with a red seven-segment display that I liked..."
Funny but I have one which updates time "via the cosmic ether", has big red 7-seg LEDs and as cherry on top it has laser LED based projector that displays same big red 7 seg digits on whatever surface one points it to - ceiling in my case. I bought it decades ago in RadioShack
Funny but I have one which updates time "via the cosmic ether", has big red 7-seg LEDs and as cherry on top it has laser LED based projector that displays same big red 7 seg digits on whatever surface one points it to - ceiling in my case. I bought it decades ago in RadioShack
so basically NTP!
There’s a time zone setting offset slider and a DST slider. I basically touch it twice a year, maybe another if I move time zones. I’ve only had to touch it for DST (never switched time zones). Takes me conservatively 10 seconds to find and flip, so it’s taken me 460 seconds or a little under 8 minutes in the past 23 years to do time adjustments.
While these efforts are definitely fun hobby projects, there are cheap reliable solutions out there with minimal intervention that consume the NIST radio signal for time.
Just for anyone interested who wasn’t aware there’s some “old school” time broadcast solutions out there too besides NTP: https://www.nist.gov/pml/time-and-frequency-division/time-di...