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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

#161

Post by ssl-3 »

crote wrote: post #160
stavros wrote: post #138

Earlier quoted context omitted.

The actual difficult part is getting a GPS signal indoors with a cheap receiver, sadly.

The obvious answer is to use a Raspberry Pi as a GPS-disciplined NTP server, of course. Place it near the window or fully outside, depending on GPS signal strength. That gives you another weekend project, and you can reuse your DIY NTP wall clock!

That never quite solves the auto-timezone/DST issue that OP wants to have work, though, does it?

If I am interpreting their request correctly, they want a wall clock that knows where it is -- and also knows what localtime is in that position on the globe.

GPS (plus some hairy lookup tables) can accomplish that.

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

#162

Post by js2 »

unsnap_biceps wrote: post #159
js2 wrote: post #114

Earlier quoted context omitted.

> 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 T̶h̶e̶y̶ ̶a̶l̶s̶o̶ ̶d̶o̶n̶'̶t̶ ̶t̶r̶a̶n̶s̶i̶t̶i̶o̶n̶ ̶D̶S̶T̶ ̶a̶u̶t̶o̶m̶a̶t̶i̶c̶a̶l̶l̶y̶,̶ ̶s̶o̶ ̶y̶o̶u̶'̶r̶e̶ ̶p̶u̶l̶l̶i̶n̶g̶ ̶t…

I have a few WWVB clocks. The ones that are on the north/south walls will never sync on their own, but east/west walls will sync just fine. I just take down the north/south clocks twice a year and lean them on a west facing wall and they'll sync overnight. I think that most WWVB clocks just don't have the size to have an omni-directional antenna.

If I have to take the clock off the wall and move it outside, I may as well set it by hand. In any case, I've tried leaving one outside facing west and it still doesn't work. I've literally never had one of these clocks work from NC.

Meanwhile, the WiFi NTP clock I purchased just works, like I always hoped the WWVB clocks would have.

https://news.ycombinator.com/item?id=46948343

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

#163

Post by toast0 »

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.

Radio clock (with reception) should be less jitter, but NTP measures round trip time, so you can estimate time in flight estimate; if your path is reasonably symetric, you could end up with less error.

I'm not sure how much it really matters though.

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

#164

Post by toast0 »

ssl-3 wrote: post #161
crote wrote: post #160

Earlier quoted context omitted.

The obvious answer is to use a Raspberry Pi as a GPS-disciplined NTP server, of course. Place it near the window or fully outside, depending on GPS signal strength. That gives you another weekend project, and you can reuse your DIY NTP wall clock!

That never quite solves the auto-timezone/DST issue that OP wants to have work, though, does it? If I am interpreting their request correctly, they want a wall clock that knows where it is -- and also knows what localtime is in that position on the globe. GPS (plus some hairy lookup tables) can accomplish that.

DHCP has an option for timezone information. Not a lot of people fill it out, though.

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

#165

Post by bux93 »

drivers99 wrote: post #31
orev wrote: post #12

Earlier quoted context omitted.

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…

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…

There's also a station in Shangqiu City, Henan province, China, BPC 68.5 kHz

Casio brands watches that receive all 6 stations as multiband-6, and older ones that don't have the Chinese signal as multiband-5.

The analog display, chronograph watches like WVQ-M410-7AJF are delightful ; you can switch to timer mode and the main hands show the time ticking down (yes, they move counter-clockwise), and then switch back to normal timekeeping mode and the hands will move around the dial to set to the correct time again. Obviously at great expense to battery life, but it's solar powered. Unfortunately it's Japanese Domestic Market only, so you need to order it from a place like discovery mall japan. (The WVQ has a flimsy plastic - if you're willing to pay a lot more you could spring for the OCWS7000E ). Citizen has some GPS set watches.

Radio time signals used by watches and wall clocks are all in the 60-77.6 Khz range, probably best suited to small receivers and low power - other radio time signals are higher frequency. In the US, WWVH broadcasts at 2.5MHz, 5Mhz, 10Mhz and 15Mhz.

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

#166

Post by bux93 »

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

An already radio controlled clock would probably be a better starting point to GPSify or NTPify too - at least the one I have already has the feature that it can move the hands to an arbitrary position (when you replace the battery and it syncs again).

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

#167

Post by tanvach »

RupertSalt wrote: post #150
tanvach wrote: post #115

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 atomi…

You do not have an atomic clock. Seiko does not manufacture “Atomic Clocks” for the $30 shelf in Target. You (and others here) don’t seem to know what an atomic clock is, or how it works, or what it costs! Your Seiko is a radio clock. It’s probably got a crystal or some other normal timekeeping gadget, and the external WWV signal is decoded to properly set it. “Atomic Clocks” are marketed to ignorant consumers who bl…

That distinction is obviously quite apparently from the context. I’m using atomic clock to be consistent with what these radio clocks are marketed as.

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

#168

Post by KaiserPro »

smithza wrote: post #126
KaiserPro wrote: post #101

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 discipl…

The DIY tuning fork clock is very cool. I am hard pressed to understand why accutron doesn't still make and sell tuning-fork watches. I really admire the creative use of resonance frequencies (not dissimilar to quartz watches but cool that you can really see the tuning fork for you watch as opposed to a diminutive quartz crystal).

They have done a re-issue, which Dole has linked to (I'm not going to lie, they do look smashing)

I think the reason why it took so long is a combination of snobbishness (its not "mechanical" enough) and cost of manufacture. I assume that most of the tooling has been lost, and it required a lot of work to re-learn how to make from scratch.

But accutrons wern't that cheap when they launched, so I think they are within 50% of their original price, judging by my half arsed inflation calculations.

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

#169

Post by stavros »

pwg wrote: post #152
stavros wrote: post #142

Earlier quoted context omitted.

Has anyone found the chip on AliExpress? I only get unrelated listings with that part number, but this is a pretty interesting chip I'd like to get a few of. An alternative would be a supercapacitor and a voltage divider connected to the ADC pin of the microcontroller. When the 5V rail dies, the supercapacitor can hold 3.3V for a few seconds while you write everything to the EEPROM.

$0.77 US single piece cost on Digikey: https://www.digikey.com/en/products/detail/microchip-technol... And, at least with Digikey, you can feel like you actually get the real part vs. some low end clone knockoff.

Comes out to $6 per part for me, with shipping, which is much more than I'm willing to pay.

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

#170

Post by pjc50 »

sowbug wrote: post #26
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'm not sure if this is the same technology, but regardless it's also cool: https://www.adafruit.com/product/1897

FRAM is extremely neat on paper, combining SRAM ish speeds with non-volatility, but adoption seems to be low. Possibly due to scaling issues. I've had a FRAM-based TI MSP430 in my random parts drawer for about a decade.
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