Seeking for a wall clock

Injection lock. You wouldn't even have to open the case.

Make a cute wooden block stand thet the clock sits on.

On a sunny day (Sat, 20 Nov 2021 03:08:27 -0800) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

panteltje20: ~ # sun

Current Date and Time: 20-Nov-2021 13:46 CET

Target Information ...

Location: 53.XN, 5.YE Date: 20-Nov-2021 Timezone: CET Sun directly north/south: 12:22 Twilight angle: -0.83 degrees (daylight) Day with twilight: 08:07 to 16:38 It is: Day (or twilight)

General Information (no offset) ...

Times ... Daylight: 08:07 to 16:38 with Civil twilight: 07:29 to 17:16 with Nautical twilight: 06:46 to 17:58 with Astronomical twilight: 06:05 to 18:40

Duration ... Day length: 08:31 hours with civil twilight: 09:46 hours with nautical twilight: 11:11 hours with astronomical twilight: 12:34 hours

panteltje20: ~ # cat /usr/local/sbin/sun sunwait report 53.XN 5.YE

sunwait is a nice utility in Linux I have substituted X and Y for my location to prevent the F35e crashing here.

On a sunny day (Sat, 20 Nov 2021 11:07:14 +0000) it happened Martin Brown <'''newspam'''@nonad.co.uk> wrote in <snaktg$5jq$ snipped-for-privacy@gioia.aioe.org>:

You mean 'never gets dark'? at very high latitudes? To know the exact latitude I asked The All Knowing Google "at what latitude does it never get dark?" The allknowing replied: The Arctic Circle, at latitude 66.56 degrees, is the circle north of which there are at least some nights (centered on the June solstice) in which the sun never sets.

Is this Google now the replacement for the acient God?

Can I hack it???? :-)

On a sunny day (Sat, 20 Nov 2021 03:10:58 -0800) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

A wall clock is nice too

but can then display anything you want, air traffic here:

Astronomers sort of do that strictly we use TDT (formerly Ephemeris Time) which is closely related to civil UTC.

But even at my latitude of 54 it doesn't get dark in summer until very late in the evening and never gets out of astronomical twilight. It confuses the hell out of LED garden lights which come on far too soon and run out of juice before it even gets moderately dark.

Nearer the equator you get a more consistent day length and a rapid transition from day to night within a couple of hours at most.

You can always hack Google - there is even a book with that title

On a sunny day (Sat, 20 Nov 2021 17:32:36 +0000) it happened Martin Brown <'''newspam'''@nonad.co.uk> wrote in <snbbg1$e6d$ snipped-for-privacy@gioia.aioe.org>:

Been a while since I bought a book.. Last one was 2014 "De keuring van een polyester zeiljacht" (translated: "examination of a polyester sailing yacht") from bol.com our local amazon.

Now with that northern route becoming ice free.....

When 2G restrictions come into power here (not vaccinated no entry anywhere) I may have to go that way AND SHOOT THE LAST POLARBEARS.

People had enough of the covid restrictions crap here.

The length of the day being rather consistent all year long was something I had not expected in Puerto Rico. When I realized my friend in Maryland was catching up with me in terms of sunset I looked it up to find the day varies between 11 and 13 hours here. I see very little difference in the transition from daylight to dark through the seasons, but then I don't notice much of a difference in Maryland either. It's pretty in both places. I think you need to get a lot further north for that to be noticed.

Sundials would work better here except that the noon shadow is to the south in the summer. I'm not sure they take that into consideration. The pointer has to lean out over the dial. North of the Tropic of Cancer a sundial can be on a south facing wall. Here that won't work for a good portion of the year unless the wall leans to the north or the dial is designed to protrude from the wall.

Interesting...

Is your AC line frequency stable, over the long term? I.e., can you use a regular old synchronous motor driven clock?

I've been running a line-frequency clock application on my time server for many months to collect data regarding the possibility of using *it* to discipline the local (CPU) clock -- which gains a fair bit of time (that network isn't routed so can't rely on Internet time servers and GPS doesn't have a good view of the sky from that location). Initial results look great! But, that's a local condition that may not apply elsewhere (with different mains quality).

Use a "clock" app that runs on a cell phone. Tape phone to wall. If a phone's display is too small, use a larger tablet or iPad. Let the cellular carrier maintain their "network time".

Will it be powered from the mains behind the clock, or be battery powered?

WiFi takes a fair bit of power.

Sylvia.

For a while I had a clock that I'd modified by removing its internal electronics, and running the motor through wires connected to some remote electronics of my own devising that were connected to a PC. It also handled the shift between daylight saving and standard time, either by running the clock fast for a time, or stopping it for an hour, as appropriate.

It worked, mostly, though I found that it had missed about ten ticks in the space of six months. The electronics had the correct time, but the clock was not displaying it. That was about 1 tick in 1.5 million. I never did determine why, but the cheap motor might have had something to do with it.

I was going to modify it for a continuous sweep motor, but moved houses, and access behind the clock wasn't so convenient.

Sylvia.

Even simpler solution is to get an Arduino mkr WiFi 1010 module and install the NTP library and the example program. With a little luck, that should be all you need

If you want to go the PI routes get the pi zero. Good luck J

Nope, no vissible trimmers at all.

I buy what is available. I would buy better if the specs at Amazon would say "this DCF clock is guaranteed to work in the south of Spain". They are intended to work in Germany and nearby.

DCF clocks simply do not work in Spain, because we are at the limit of the area DCF emitter is intended to cover. See the graph:

And then see the graph just below that one that shows signal in Nerja, Spain («DCF77 signal strength over a 24-hour period measured in Nerja, on the south coast of Spain 1,801 km (1,119 mi) from the transmitter. Around 1 AM it peaks at ≈ 100 µV/m signal strength. During the day, the signal is weakened by ionization of the ionosphere due to solar activity.»)

Very unlikely that a clock using one AA cell, not even two cells, can work reliably with that signal.

The obvious solution is to use WiFi synced clocks instead. Or instrument grade DCF clocks, which I don't know how to obtain, and then whether I can afford them.

So now I'm in the process of using an old tablet as clock. No idea how long it will survive.

An ebook with epaper display would be interesting if it can be repurposed as wall clock. Maybe a Linux tablet, if cheap enough.

I no longer enjoy that amount of detailed work. A ready to use kit I would very probably buy and do, but from scratch, no way. I no longer have my PCB etching materials, and I can not solder SMD.

LOL, I'm not going to try that on a microscopic circuit :-D

No, my Xtal clocks do not have any visible adjustments from outside. One has mechanical hands and the other is an IKEA thing. Several others are AC power "programmers".

Maybe expensive clocks are accurate or adjustable, but that is not the case.

Yes, I also hate summer/winter clock changes.

Curious.

When I try Amazon for that, I get T shirts instead.

Stable as on all of Europe, we are in sync :-)

They don't seem to make wall AC clocks much. There is the µW oven, of course, but we have power failures or glitches and that clocks resets.

Yes, that's what I am preparing. I have an old unused tablet which I'm going to use for that. I just bought an AC adapter and USB cable to power it on constantly. No idea if it will survive many moons.

Also has reasons for more grumbling from me: if it powers off or reboots, it forgets the WiFi credentials. Possibly an update would solve that issue, but the factory Play Store refuses to work unless I enter google credentials; I'm not going to enter my own credentials on a gadget that can't be password protected, so I have to create a new google account solely for this purpose. Seems stupid, but the way to go.

Then I need to find a widget or app that fills the display with a clock, perhaps also weather. Some want to put adverts, too!

True.

If it were a Linux tablet, with epaper for display, then I would put the WiFi on a timer to run once every 24 hours, say, and the batteries might last a week. I would then charge from a socket I already have that is not on the entire day.

I found an interesting clock on Amazon, "Echo Wall Clock". Caveat: it needs to be 9 meters at most from an "Echo" device. Maybe uses Bluetooth to sync to the main Echo device, but 9 meters is not acceptable.

Interesting idea.