[HN Gopher] Converting a $3.88 analog clock from Walmart into a ...
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Converting a $3.88 analog clock from Walmart into a ESP8266-based
Wi-Fi clock
Author : tokyobreakfast
Score : 343 points
Date : 2026-02-09 16:26 UTC (6 hours ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| kotaKat wrote:
| Of note, having recently shopped at Walmart for a self-setting
| alarm clock (what I once knew to be "atomic"):
|
| Apparently the entity today known as Sharp sells "AccuSet(tm)"
| branded clocks that "automatically set time"... but they're just
| factory pre-set with a button cell and they include a slider on
| the bottom to set a timezone offset (only for US timezones). If
| you're lucky, the clock's battery is still good and the clock
| "set itself" out of the box several minutes late.
|
| If you're unlucky - surprise, you get to manually set the time
| anyways.
|
| https://www.amazon.com/Sharp-Digital-Alarm-AccuSet-Automatic...
| relaxing wrote:
| You want a self-setting radio clock that receives the LF
| broadcast from WWVB.
|
| There was a kerfuffle a few years back about the funding for
| the station being cut, but luckily that did not come to be.
| orev wrote:
| These clocks are irritating because they show up in the results
| when searching for "radio atomic clock" and similar, and it can
| be very hard to figure out if they actually use the WWVB radio
| signal. I've concluded that none of them do, because WWVB is
| only reliable in (most parts) of the US, and companies only
| want to make things that appeal to a global audience now. La
| Crosse seems to be the only one that makes them, and
| unfortunately most of their designs lack any style (i.e.
| they're ugly).
| geerlingguy wrote:
| It's like they hired a design firm in the early 00's and
| decided that design language is the peak of human horology...
| I wish they'd make a couple new designs.
| drivers99 wrote:
| There are actually other time signals around the world.
|
| I had a Casio wave ceptor (one with analog hands which it
| doesn't look like they sell anymore; I should have kept it).
| Anyway, looking at a model that's currently available
| (WV-200R, but there are 2 other models available), its manual
| says it gets signals from "Germany (Mainflingen), England
| (Anthorn), United States (Fort Collins), [and] Japan."
|
| I was curious so I looked those up:
|
| Mainflingen DCF77 77.5 kHz
|
| Anthorn 60 kHz
|
| Fort Collins WWVB 60 kHz
|
| Japan looks like they have Mount Otakayoda 40 kHz, and Mount
| Hagane 60 kHz.
|
| There are also some other countries that have time broadcasts
| (e.g. France. Anywhere else?) but not that that watch uses.
| jonathanlydall wrote:
| Clocks which are designed to be able to auto set their time in
| the US will actually also do the auto setting at least as far
| away as Johannesburg, South Africa.
|
| I know this because when my mother was visiting the US over a
| decade ago, she found a clock she felt was aesthetically
| perfect for her psychology practice room at her house.
|
| Twice a year the clock changes its time to be 10 hours (or
| thereabouts) behind, no doubt due to daylight savings change
| over.
|
| So she has to readjust the time whenever this happens which she
| says she doesn't really mind.
| DesiLurker wrote:
| makes me wonder what if I just wanted to sync with nfc every once
| in a while. wifi seems overkill for this. maybe it could be done
| much cheaper with nfc sync witha phone twice a year?
| yjftsjthsd-h wrote:
| ESPs are so cheap that you couldn't possibly save _very_ much
| money, and the way economies of scale work it may or may not be
| cheaper to use NFC anyways.
| phh wrote:
| An ESP32-C3 Super Mini can be found for below 3$ (cheapest I
| had was 1.58EUR). Since the original clock is 3.88$, it can't
| be that much cheaper.
| sowbug wrote:
| We've been shopping for a simple bathroom clock to replace our
| final Amazon Echo and leave that increasingly dystopian
| ecosystem. There are some models that use Bluetooth on your
| phone to sync the time. I could imagine BLE being a good low-
| power and relatively stateless solution. But given our goals,
| we're not going to install an app on a phone just to maintain a
| wall clock. (I'd be fine if Android provided BLE time sync as a
| built-in service.)
| russdill wrote:
| Home assistant has pretty good BLE capabilities. But
| honestly, as has already been pointed out wifi is already
| really cheap.
| pantalaimon wrote:
| You often have a radio clock source like DCF77 that all those
| radio controlled clocks use
| albertsikkema wrote:
| Great idea!
| teraflop wrote:
| Cool project!
|
| The most interesting part, IMO, is the "SRAM with EEPROM backup"
| chip. It allows you to persistently save the clock hands'
| positions every time they're moved, _without_ burning through the
| limited write endurance of a plain old EEPROM. And it costs less
| than $1 in single quantities. That 's a useful product to know
| about.
| sowbug wrote:
| I'm not sure if this is the same technology, but regardless
| it's also cool: https://www.adafruit.com/product/1897
| mftrhu wrote:
| Not quite - the chip the article refers to is the 47L04 [0],
| which is "just" NVSRAM built out of a RAM + EEPROM. I _do_
| agree on FeRAM being cool, though - I have a few I2C chips en
| route, and I can 't wait to get my hands on them.
|
| [0] https://www.microchip.com/en-us/product/47L04
| qwertox wrote:
| Thanks to both of you for bringing FRAM onto my radar!
| summa_tech wrote:
| You could also consider MRAM. Which is available in larger
| sizes - up to 4 Mbit on SPI bus in the MR20H40, and 128
| Mbit in EM128LXQ (but it gets unreasonably expensive when
| this big).
|
| https://www.everspin.com/family/mr20h40?npath=259
| ssl-3 wrote:
| That's really neat. TIL.
|
| So the way this works seems to be this: It's an SRAM and an
| EEPROM in one little package along with a controller that talks
| with each, with a little capacitor (this clock uses 4.7uf)
| placed nearby.
|
| The SRAM part does all of the normal SRAM stuff: It doesn't
| wear out from reading/writing, and as long as it has power it
| retains the data it holds.
|
| The EEPROM does all the normal EEPROM stuff: It stores data
| forever (on the timescale of an individual human, anyway), but
| has somewhat-limited write cycles.
|
| The controller: When it detects a low voltage, it goes "oh
| shit!" and immediately dumps the contents of the SRAM into
| EEPROM. This saves on EEPROM write cycles: If there are no
| power events, the EEPROM is never written at all.
|
| Meanwhile, the capacitor: It provides the power for the chip to
| perform this EEPROM write when an "oh shit!" event occurs.
|
| When power comes back, the EEPROM's data is copied back to
| SRAM.
|
| ---
|
| Downsides? This 47L04 only holds 4 kilobits. Upsides? For
| hobbyist projects and limited production runs, spending $1 to
| solve a problem is ~nothing. :)
| bonsai_spool wrote:
| What's the purpose of using an LLM to write a comment here?
| ssl-3 wrote:
| "Hey, someone _on the Internet_ used decent diction!
| Obviously, this means I must accuse them of being a bot! "
|
| (Hey Dang. Can we get a ban button? There's a few people
| here that are impossible to conduct rational discourse
| with. My sanity would improve if they were simply gone from
| my view.)
| ninalanyon wrote:
| You could create a browser user script to do it locally.
| ssl-3 wrote:
| That's not a terrible idea.
|
| An extra UI element or two should be enough. Maybe with
| sticky options for collapse-by-default or hide-by-default
| at the top of each HN comment section.
|
| And the list of usernames can be stored and edited in the
| purveyor's HN bio (in plain text, like a monster), so
| that it works automatically across devices.
| bonsai_spool wrote:
| You've edited the response since you posted it. I think
| there's a difference between diction and the standard
| output of ChatGPT et al.
| ssl-3 wrote:
| I'd like to say that I'm sorry that you feel that way,
| but frankly: My ability to feel anything empathetic about
| you dwindles by the moment.
|
| Please stop fucking with people in this way. It's
| callous, unnecessary, and antithetical to the greater
| good. We don't come here to get accused of things.
|
| (edit: Today, I learned about the existence of a chip
| that does a clever thing. That made me curious: After
| all, I've been passively wondering for -decades- about
| how electronic things remember their previous state
| without power, and without hammering an EEPROM.
|
| I could have learned more about this at any time over the
| years, but I just never bothered with doing so.
|
| And today, it was right in front of my face -- with a
| part number! That gave me a very easy place to start, so
| I started.
|
| I read up on it a bit using the datasheet and a
| whitepaper. I learned some about how it does that clever
| thing, and I wrote a few sentences about this new-to-me
| stuff in a way that I felt would be approachable and
| appreciated by this particular audience.
|
| _That 's_ what we're here for -- to be curious, to share
| ideas, and to learn stuff from others. Not for fucking
| with people.)
| Dachande663 wrote:
| Upvoted because this stinks to high hell of an LLM
| response. Half the GPs comments seem to be in a similar
| vein. It's such a shame but you can't fight the trolls so
| don't take it to heart.
| monocasa wrote:
| I do like the frams too for similar use cases.
|
| Particularly I like that I can get those large enough to stick
| a ring buffer from debug out on them as well and get crash logs
| from embedded systems despite the debug uart not being tethered
| to a dev machine.
| jccooper wrote:
| See also the "Ventinari clock":
| https://github.com/iracigt/ventinari-clock
| https://www.akafugu.jp/posts/products/vetinariclock/
| sowbug wrote:
| If you like this but don't want to get your hands as dirty, have
| a look at the Crazy Clock:
| https://www.tindie.com/products/nsayer/crazy-clock/
|
| I got one for my daughter. The erratic ticking eventually became
| a distraction when she was studying, so we have retired it for
| now. But we got a lot of amusement out of it.
| avidiax wrote:
| > Early clock - keeps time anywhere between 0 and 10 minutes
| fast. For those who like to set their watch ahead to avoid
| being late. This clock keeps you from trying to "compensate,"
| because you never know how early it is at the moment.
|
| That's pretty genius for many ADHD-type folks. Only problem is
| a modern household has many clocks in view, so you'd need to
| commit to just not setting them.
| javawizard wrote:
| Oh now that would be a fun version 2 challenge: have all the
| clocks in one household synchronize such that they're all
| early by the same amount at any given time.
|
| Easy enough for wifi enabled ones: a UDP broadcast to
| discover other clocks on the network, then sync how you will.
|
| For non-wifi-enabled clocks, perhaps something like a CH572
| would do the trick: a $0.20 RISC-V microcontroller with BLE
| support that all the clocks in the same vicinity could use to
| talk to each other.
|
| You could really mess with your neighbors if they had the
| same clocks and you were within range...
| seg_lol wrote:
| You don't already do this with the NTP servers under your
| control?
| javawizard wrote:
| If I had any NTP servers under my control, I probably
| would :)
| password4321 wrote:
| Yes I'd have to convince Apple to play along on the iPhone
| and watch.
| Spivak wrote:
| If you want a pure software solution get yourself an old atomic
| clock and https://github.com/jj1bdx/WWV play some tunes to set
| the time.
| bityard wrote:
| The repo you linked to is a WWV simulator, WWV broadcasts the
| time via _audio_ (double-sideband amplitude modulation) at
| various fixed HF frequencies. SOME clocks might be able to
| automatically receive and decode this signal, but not many.
| There is also a web version here: https://wwv.mcodes.org
|
| Radio controlled ("atomic") clocks get their signal from WWVB,
| a long-wave station in Colorado. Its signal is just a carrier
| and data is encoded via pulse-width modulation and phase
| modulation. People have built local, low-powered WWVB
| transmitters to sync their watches and so forth in areas where
| WWVB is hard or impossible to receive. It's not a good idea to
| build one of these unless you REALLy know what you're doing
| because radio signals can travel farther than you expect, and
| the FCC takes a rather dim view of intentionally broadcasting
| your own signal (to any distance) without a license to do so.
| buescher wrote:
| There's a digital code as part of the WWV transmissions (!)
| but you're right that the typical "atomic" clock doesn't
| sychcronize to the HF stations.
|
| There are weak wwvb simulators out there as phone apps and
| such that depend on using EMI to sync your clock. Like the
| old AM radio bus noise music hack.
| https://github.com/kangtastic/timestation?tab=readme-ov-
| file...
| riskable wrote:
| I want to see someone convert one of those cheap projection
| clocks like this: https://www.homedepot.com/p/La-Crosse-
| Technology-5-in-Color-...
|
| The red projection is _just_ the right brightness (at night) but
| it sucks that it 's not wifi-enabled so you can't just get it to
| NTP sync (or hook up a GPS receiver). The projector part of the
| clock is a separate device that's attached to it via a ribbon
| cable. I would reverse engineer it myself but I haven't got the
| time.
|
| Ideally, I'd want a matrix of LEDs projected on to the ceiling so
| I could get more info than just the time. Such clocks exist but
| they're super duper expensive! Example: https://buyfrixos.com/
| lostlogin wrote:
| Undermining the spirit of HN: By the time you've spent a few
| hours hacking away and bought any parts, that price is probably
| not too bad.
| stavros wrote:
| That's assuming you don't like hacking and would pay to not
| have to do it, which is generally not the case around here.
| lostlogin wrote:
| I'm think you can go further than that.
|
| Days spent modifying cheap electronics is absolutely
| encouraged.
| hackingonempty wrote:
| Buy the premade thing and hack something new.
| seg_lol wrote:
| Cheap electronics are just the feed stock, the basis
| function for your new creation. Why start with raw matter
| when you can get fully formed matter for less.
| mmsimanga wrote:
| +1 I have a couple of digital.clocks from Temu. They look nice
| but cannot keep the correct time. They slowly edge ahead and in
| a month they are about a minute ahead. It is annoying having to
| correct the clock and would be great if they time from WiFi
| connected source.
| stavros wrote:
| If you're looking for something low brightness, I made one:
| https://www.stavros.io/posts/i-made-another-little-bedside-c...
| ElevenLathe wrote:
| The one you linked claims to have "Atomic Time" which usually
| means syncing by radio from WWV/WWVB. I have several cheap
| wallclocks like this (though none with a projector) and they
| are always accurate with no noticeable drift AFAICT. Have you
| tried that particular one and found its accuracy wanting? I
| think, in principle at least, there should be less jitter in
| this method than using NTP over a computer network.
| cptskippy wrote:
| With a resolution of one second, I think most people would be
| hard pressed to distinguish between NTP and WWV/WWVB time
| keeping devices.
| Animats wrote:
| Right. WWVB clocks running off the 60KHz pretty much solve
| the clock problem in the US. All my clocks at home are basic
| LaCrosse analog clocks. They have the internal sensors needed
| to tell when each hand is straight up, so they can set
| themselves without user input. On power up, they step until
| the hands are straight up, then sync when they get an update.
| You have to set the time zone with a switch when installing.
| Only the four US time zones are available. Battery life is
| 1-2 years, which is pretty good for a device with a radio.
|
| There are UK and Japan clocks that work similarly, but use
| national time sources. There are G-Shock watches which
| synchronize from multiple sources. While running on solar
| power. Those keep accurate time with no maintenance. That's
| an impressive achievement.
| js2 wrote:
| > WWVB clocks running off the 60KHz pretty much solve the
| clock problem in the US.
|
| YMMV depending upon location. I've never gotten a WWVB
| clock to work in North Carolina. On the East Coast, the
| signal maybe sorta works for a few hours overnight:
|
| https://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi
|
| They also don't transition DST automatically, so you're
| pulling them off the wall twice a year unless you're in one
| of the rare US locations that don't adhere to the DST
| silliness.
| zymhan wrote:
| I'm fairly certain the radio time signal has a mechanism
| to convey daylight savings, I've had alarm clocks that
| managed DST without any input.
|
| > The DST status bits indicate United States daylight
| saving time rules.
|
| https://en.wikipedia.org/wiki/WWVB
| alnwlsn wrote:
| Depending on how dark your room is you might get by with an
| ordinary but bright LCD screen and a camera lens. There's a
| pretty common 240x240px, 1-inch square TFT display on amazon or
| other usual places you might start with.
| btheconqueror wrote:
| Some clocks also update over radio. Oregon Scientific used to
| make the best bedside atomic clock ever. Super simple, with the
| projector, was an atomic clock that updated automatically via
| radio and had a pleasant, crescendo alarm that would start off
| nice and get more aggressive. They don't make it anymore :/
| avidiax wrote:
| How does this keep track with DST?
|
| Looking at the code [1], it looks like if the actual time is 1
| hour ahead of the displayed time, then we get 10 pulses per
| second to leap forward. Otherwise, the clock stops running for an
| hour to fall back.
|
| https://github.com/jim11662418/ESP8266_WiFi_Analog_Clock/blo...
| sowbug wrote:
| You have two choices: either assume everyone is asleep at 2 am
| and won't notice when it happens, or else advance 11 hours. My
| LaCrosse clock does the latter.
| gspr wrote:
| And that's pretty much fine for a project like this, seeing as
| most (all?) locations jump you between DST and not DST at
| night. So the clock will be off at most for an hour during the
| night.
| floatrock wrote:
| Yeah, project needs a time-lapse video of their analogue DST
| transition event.
| Dachande663 wrote:
| I'm currently making something similar but using a BKA30D-R5 (a
| dual stepper motor used in car dashboards) and a hall sensor to
| zero the hands.
| russdill wrote:
| Yes, this project screams for some kind of sensor to detect
| when the hands reach some known position.
| Dachande663 wrote:
| Yeah, it's super quick to start with a MK I eyeball to set
| them, but having a sensor just avoids any drift. I got away
| with using one by taking a reading and moving the other hand
| to check they weren't on top of each other already, and then
| doing a full rotation between readings.
| dheera wrote:
| Some years ago I made a ESP-based clock that used 60 LEDs in a
| circle that project RGB shadows via a cone at the center. I used
| the same WeMos D1 Mini board.
|
| https://github.com/dheera/shadow-clock/
| bityard wrote:
| I remember seeing this on Hackaday. Very clever idea!
| MrVitaliy wrote:
| Cute, but the original clock used to run on AA battery that needs
| a replacement every two years or so, and now it needs a power
| supply. Or some big battery recharge/replacement every few hours
| maybe days.
| debbiedowner wrote:
| How different is this to something you can buy like:
| https://www.amazon.com/ihreesy-Movement-Mechanism-Silent-Rep... ?
| TechSquidTV wrote:
| Well I notice that one is $36
| xandrius wrote:
| One is hacked and the other one is bought?
| freedomben wrote:
| Hell yeah, this is some badass hackery, and the type of stuff I
| _love_ seeing on HN. In the last decade or so as more and more
| stuff becomes locked down and hacker unfriendly, I 've found
| myself longing for simple things I can hack on. If I ever get to
| a point where I don't have to work for a living, one of the
| things I'd like to do is build everything from little gadgets up
| to major appliances that are simple, reliable, and hackable for
| people who want to. It pains me that my appliances have full
| computers driving them but I can't get access to them. Kudos for
| this awesome work and phenomenal write-up!
| ortichic wrote:
| Sorry if this is a dumb question, but do you guys not have radio
| controlled clocks outside of Europe? If I got it right, the only
| purpose of this project is to always display the correct time.
| Radio controlled clocks do exactly that. They are cheaper than
| the one ESP board, and run years on a single AA battery. No WiFi,
| tinkering, setup, or cables necessary
| qwertygnu wrote:
| Googled "radio controlled clock" and seeing results from
| $20-$200, lots of inconsistency in what the product is.
| alnwlsn wrote:
| These are usually marketed as "atomic time" or "atomic clock"
| here in the US.
| jcalvinowens wrote:
| If you think _this_ is overengineered, I built one that will
| really offend you: https://github.com/jcalvinowens/wallclock :)
|
| The point is to have fun and learn something, not really to
| solve a problem in a practical sense. The radio controlled
| clocks are _extremely_ unreliable where I live.
| haunter wrote:
| There are time signal stations all over the world, WWV is the
| most prominent US one
| https://en.wikipedia.org/wiki/WWV_(radio_station)
|
| https://en.wikipedia.org/wiki/Radio_clock#List_of_radio_time...
| js2 wrote:
| We do, but I've never had a WWVB clock work for me in North
| Carolina. I've tried a few of them. The US is a big place and
| for whatever reason, there aren't that many clock signal
| transmission towers (AFAIK, the only one in the US is in
| Colorado).
| moduspol wrote:
| I'm in WV, but could only get my clock to set itself when put
| on the correct SW-facing wall.
|
| Obviously it defeats the purpose a bit if I need to move my
| clock to a different wall and wait 12-24 hours for it to set
| itself.
| KaiserPro wrote:
| There is (https://www.nist.gov/pml/time-and-frequency-
| division/time-se...) and in some conditions you can receive the
| time signal in the UK.
|
| Our office manager bought some US tuned radio wall clocks, and
| every now and then they would jump 8 hours forward. I assume it
| was down to solar weather making propagation changes
| (https://en.wikipedia.org/wiki/Sporadic_E_propagation)
| gambiting wrote:
| That is very cool.
|
| As for the problem of detecting the current position of hands -
| Casio solved in in watches with their Tough Movement mechanism,
| where there is a tiny tiny hole in the dial with a sensor behind
| it - the watch will check if the hands are over it when expected,
| and if not, automatically adjust - so even if a watch suffers a
| major impact that might move the hands, they will re-allign
| themselves. Such a clever and simple solution.
| js2 wrote:
| This is great. I spent years looking for an affordable battery-
| powered WiFi clock that syncs via NTP since where I am, the WWVB
| clocks never pick up the radio signal.
|
| I never considered making my own. Anyway, about two years ago
| this option popped up on Amazon. I've been happy with it:
|
| https://www.amazon.com/OCEST-Wall-Clock-12Inch-Auto/dp/B0DJS...
|
| I'm guessing internally it's not much different than the DIY
| clock in this submission.
| moduspol wrote:
| Thanks for sharing this. I, too, have spent years trying to
| find an analog-style clock that is completely hands-off for
| adjustments (power outage, DST, drift correction) and it looks
| like this one handles it all.
|
| It feels like in 2026 this should be something default and
| assumable, but alas, it is not.
| accrual wrote:
| It'd be interesting to see the logs or data on how the physical
| movement falls out of sync. It probably even correlates with
| temperature and humidity.
| retired wrote:
| I'm curious how long it takes for the hands to drift to the point
| where the time difference is perceivable. Luckily the 30
| millisecond pulse time is configurable.
| montroser wrote:
| What I really want is one of these powered by gps. The time
| already comes for free in the signal, and from your location you
| can derive the time zone. That way DST is accounted for
| automatically, but you don't have to set up and rely on wifi.
| This would be truly zero-config and always correct.
| womod wrote:
| There's quite a few clocks available that get their time over
| the air from the NIST WWVB radio station[0]. They usually have
| a little switch on the back if your area does/doesn't observe
| daylight savings.
|
| [0] - https://www.nist.gov/pml/time-and-frequency-
| division/time-di...
| IncreasePosts wrote:
| You would still need some kind of configuration because the
| start of DST can change year to year, and this is not accounted
| for in the time signal from GPS
| montroser wrote:
| Good point that DST dates can technically change -- but in
| practice it doesn't really change on a year-to-year basis.
| The current law establishing the start and end dates in the
| US has been in effect unchanged for the last ~20 years.
| ssl-3 wrote:
| GPS isn't too hard, either.
|
| The receivers are inexpensive ($5-$10 for the kind of accuracy
| that's useful here) and it's not hard to parse the NMEA strings
| and PPS they output into a spooky-accurate internal clock. It
| only takes a few connections and an antenna to integrate GPS
| into an MCU like an ESP (or an SBC like a Raspberry Pi or a
| whatever).
|
| Like, really: The hardware is ridiculously easy.
|
| The only difficult part is the code. But as we can see from
| this posting, the clock-driving bits are already written and
| are available for use.
|
| Just graft in the GPS parts instead of the NTP parts, add your
| DST/location rules if you really must (hint: that part is
| harder than it sounds), and send it.
|
| (And if the code still seems arduous, then remember: This is
| the kind of work that a reasonably-focused person who is armed
| with a decent bot can put together over a cup of coffee or two,
| even if they don't speak C. It may be popular here to poo-poo
| the bot here, but it's completely OK to get some help. Don't
| let pride get in the way of having fun, learning things, and
| building neat stuff.
|
| The tailor doesn't lament the invention of the cotton gin.)
| SoftTalker wrote:
| Now do a old fashioned mechanical pendulum clock. You'd probably
| need some kind of worm gear drive to move the pendulum bob up and
| down.
| cyberax wrote:
| I was looking at the way they did the position sync. And they
| didn't :(
|
| OK, here's how I'd do it: add small magnets at the bottom of the
| clock hands, and use the ESP's built-in Hall effect sensor to
| detect them. You can distinguish between hands using the magnetic
| field orientation.
| rballpug wrote:
| Keeping time in terms of hash-sigs that are in 64 bit
| architecture instance.
| timonoko wrote:
| On that note: _Converting EUR0 scrap into EUR400 video editing
| deck_. https://www.youtube.com/shorts/KlWYC6mzVkQ
|
| https://github.com/timonoko/Jogwheel
| kfarr wrote:
| What a great idea. Legacy VCR controls upcycled for digital
| control! There's a lot of those old decks and LANC deck
| controllers lying around...
| timonoko wrote:
| This is a hard problem. Solvable only with try and error.
|
| Those signals are just weird mess of coils, switches and
| resistors.
|
| ESP32 clock speed may also be a contributing factor.
| greenie_beans wrote:
| lol i just bought this same clock cuz it was cheap and had no
| tech except the clock
| j45 wrote:
| Keeping the clock analog was clutch.
| ChuckMcM wrote:
| Pretty awesome. The only thing I would change is to put a USB
| battery between the usb wall power and the D1 mini. That way for
| power outages of < a couple of days or so you're clock will be
| fine.
| diimdeep wrote:
| I've tried similar project, as it turns out it is surprisingly
| hard to reliably move second's hand and not wobble in place, you
| need to drive quartz motor so precisely to make gears move.
|
| Post don't go into detail about schematic, but resistors and
| diodes around motor is to properly drive motor and protection
| from Inductive kickback (Flyback)
| https://www.microtype.io/blog/h-bridge-circuit-design
| staplung wrote:
| This is cool but it seems like it would be liable to drift. I.e.
| it "knows" the correct time but doesn't have any way to figure
| out that it's been driving the movement fast or slow by some
| number of milliseconds. Eventually, that will pile up to the
| point that it's not any better than running the thing off of
| batteries.
|
| As the author points out, the cheap quartz mechanism has no way
| of reporting the position of the hands (other than the hands
| themselves) and that you have to set the PULSETIME constant by
| the right number of milliseconds. If you're off by even a
| millisecond, that's going to accumulate quick enough that it
| would make a difference over even a single day, wouldn't it?
|
| EDIT: as some have pointed out, the Lavet stepper theoretically
| accounts for this in that it steps exactly one tick after so many
| oscillations. That number of oscillations does not change so
| that's all you need to get right.
|
| However, that basically just kicks the can down the road a bit in
| that if each step is not exactly 1/60th of a circle or bits wear
| down or get sticky or you have analog noise in there you will
| presumably still have a source of biased drift that you won't be
| able to detect. But maybe those affects are small enough that
| they don't matter for a wall clock.
| bazodedo wrote:
| The pulsetime is just to advance the clockwork one step, and is
| kept fixed, the advancement driven by the mechanism is
| discrete. As long as you keep track of the count, you wont
| accumulate drift. The adjustment is to get that stepping
| working, if it doesnt miss a step, youre good.
| mlhpdx wrote:
| In a perfect world, yes. But mechanisms aren't perfect and
| it's entirely possible if not likely that steps will be
| missed as friction increases over time and things wear.
|
| I'm not saying these things matter much in this context.
|
| The clock will still be far more accurate than purely
| mechanical version. And, re-synchronizing it is as trivial as
| turning the knob, just as you would for the all mechanical
| mechanism.
| KaiserPro wrote:
| its a fairly reliably stepper motor system. You're right it
| will degrade over time, you'd be surprised how many steps
| it can do before it degrades.
| picture wrote:
| The escapement is "synchronous" in that the motion is
| controlled by the number of pulses applied to the motor over
| time rather than the duration/width of each pulse. The
| pulsetime constant is only to accommodate mechanical/analog
| differences with the driving circuitry, from what I understand.
| https://en.wikipedia.org/wiki/Lavet-type_stepping_motor
| lelandbatey wrote:
| That's fascinating; the Lavet-type stepping motor acts as an
| escapement all on it's own by being a very simple stepper
| motor, so you don't end up needing a miniature version of a
| classic mechanical escapement, which is what I'd always
| imagined in my head when thinking about how cheap quartz wall
| clocks worked.
|
| https://en.wikipedia.org/wiki/Escapement
| PlatoIsADisease wrote:
| I'm mostly interested in what goes wrong.
|
| I've made enough of these projects to know that ~75% need
| modifications that were not anticipated. For instance, I made a
| freezer temp sensor to php email for cases where the freezer
| stops working... but when I opened the freezer, it would send an
| email. I needed to sample for 30 minutes or something.
|
| Maybe this was simple and you will be part of the 25% that work
| perfect and need 0 updating.
| SoftTalker wrote:
| Yes most things that monitor a sensor in the real world can't
| react to instantaneous readings. They need to use an average of
| samples over some time period. Also due to hysteresis, you have
| to allow time to see any changes in state in response to
| changes in inputs. Most real-world systems don't respond
| immediately.
| amelius wrote:
| What's the best way to periodically get time and date if your
| customers are big businesses with hostile IT departments?
| btbuildem wrote:
| GPS unit
| Neywiny wrote:
| A great solution I've used plenty of times is to query websites
| like google.com. I use it whenever my rtc on my Linux laptop
| gets reset (as long as it's still in my history. Otherwise I
| just set it manually).
|
| https://unix.stackexchange.com/a/400176
| greenail wrote:
| you can buy dual coaxial shaft steppers ( X40 ) for car
| instrument panels open them and remove the hard stops. A very
| small magnet and 2 hall sensors gets you end stops.
| KaiserPro wrote:
| If your budget is a bit more, and you want to hear a massive
| clunk every 30 seconds rather than a soft tick _and_ you want to
| drive 2 ' (60cm) hands, then you might want this:
| https://waitingtrain.blogspot.com/2015/05/a-large-gents-turr...
|
| The smaller ones look the same but are less beefy.
|
| I used one to make this clock:
|
| https://www.secretbatcave.co.uk/projects/electromechanical-c...
|
| Which instead of using a well disciplined time source, uses a
| tuning fork and 74xx logic to drive it
| teekert wrote:
| On this topic. Do WiFi signals contain time (unencrypted)? If so
| why does my oven not pull time from the air and needs adjustment
| every 2 months? If not, why are APs not defacto time beacons for
| all sorts of non-smart appliances (and clocks)?
| cardiffspaceman wrote:
| I worked with CFG80211/MAC80211 on an old Linux kernel years
| ago. I don't think time of day is in any packet.
| ianburrell wrote:
| I have thought that could use Matter for time sync. It works
| with both Wifi and Thread. I don't think there is a time
| message. I also don't know if it has public broadcast since
| Thread needs pairing to work.
|
| The advantage is that smart devices might have Matter support
| already. People with Matter devices will have border routers,
| which are perfect place for running NTP and broadcasting time.
| cbdevidal wrote:
| I've wanted to do this because there's a zillion cool clocks out
| there that use a similar movement. I'd also wanted to make it
| battery powered which means doing NTP update only once per day
| (or less). Doubt that is realistic, tho.
|
| Maybe embed Hall sensors and detect when the hands are in a
| certain position and when all three line up wake the ESP32, do an
| NTP update, tick it forward to where it should be, then go to
| sleep. Probably still use too much power, especially the Halls.
| cweagans wrote:
| Use reed switches behind the clock face and magnets on the
| (presumably) different length hands instead of hall sensors.
| NTP sync once per day is more than adequate for household
| timekeeping - it might drift a few seconds here and there, but
| that's fine for most people?
| cbdevidal wrote:
| Yeah, reeds make more sense. I'd stagger them so that when
| the hour is at 12, minute at 3, second is at 6, all three
| reeds (wired in series) wake the microcontroller.
| tanvach wrote:
| Related - we have an atomic Seiko wall clock expecting to have
| the time automatically adjusted by the WWVB LF atomic clock
| broadcast. Turns out, the signal is very weak where we now live.
| Manually setting the time on these atomic clocks is a HUGE pain
| (beware!).
|
| Turns out it's possible to emulate the atomic clock signal quite
| easily with a Raspberry Pi, or in my case I put together Arduino
| code that can emulate atomic clock broadcasts from around the
| world using an ESP32 module using NTP servers:
| https://github.com/tanvach/clocksync
|
| The history of these atomic clock broadcast signals and their
| differences in different countries is quite fascinating.
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