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Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

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Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#91

Post by KaiserPro »

mlhpdx wrote: post #85
bazodedo wrote: post #81

Earlier quoted context omitted.

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.

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.

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.

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#92

Post by ssl-3 »

bonsai_spool wrote: post #88
ssl-3 wrote: post #65

Earlier quoted context omitted.

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…

What's the purpose of using an LLM to write a comment here?

"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.)

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#93

Post by monocasa »

teraflop wrote: post #5

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.

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.

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#94

Post by KaiserPro »

ortichic wrote: post #37

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

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)

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#95

Post by btheconqueror »

riskable wrote: post #13

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 en…

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 :/

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#96

Post by lelandbatey »

picture wrote: post #83
staplung wrote: post #78

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 h…

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

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

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#97

Post by buescher »

bityard wrote: post #46
Spivak wrote: post #10

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.

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 carrie…

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...

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#98

Post by cptskippy »

ElevenLathe wrote: post #33
riskable wrote: post #13

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 en…

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.

With a resolution of one second, I think most people would be hard pressed to distinguish between NTP and WWV/WWVB time keeping devices.

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#99

Post by summa_tech »

mftrhu wrote: post #51
sowbug wrote: post #26

Earlier quoted context omitted.

I'm not sure if this is the same technology, but regardless it's also cool: https://www.adafruit.com/product/1897

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

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

Re: Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock

#100

Post by ninalanyon »

ssl-3 wrote: post #92
bonsai_spool wrote: post #88

Earlier quoted context omitted.

What's the purpose of using an LLM to write a comment here?

"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.)

You could create a browser user script to do it locally.
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