Clocks

[lnr]

A short list of clocks which do not update themselves:

• Matthew's bedside alarm clock. Several experimental button pushes to remember how.
• Matthew's travel alarm clock. Fairly self explanatory
• Small clock in the dining room. Turn the time knob, not the alarm one!
• Oven. Doddle.
• Microwave. A bit of poking, but not too bad.
• Bike computer. Putting this one off as it requires a cocktail stick and remembering the right runes so you don't accidentally completely reset it. Write down the odo distance first before attempting!

The electronics (and the big living room wall clock, and the heating controller) all look after themselves, which is just as well, as there are quite a lot of them.

Comments

[simont]

I'm very nearly down to 0 clocks to update in my house.

In principle every clock I use is supposed to auto-update for daylight saving, either by receiving the MSF radio signal, or having a time zone database so that it knows UTC and figures out current local time. Alas, in practice, one of my MSF-receiving clocks seems to be hard of hearing – I have occasionally noticed it catching a snippet of the radio signal and correcting itself, but it often goes days if not weeks without being able to hear it at all, so I change it on the day by hand.

(Annoying, because it does know the date, so if only it had a time zone database, it wouldn't need to rely on the daylight-saving bit in the MSF signal!)

I'd also like every clock I use to keep itself accurate from an external source (again, either MSF, or NTP over my house network). I'm doing less well there, because as well as the unreliable MSF clock, my heating controller also has no synchronisation and I have to periodically correct its drift.

And I say "every clock I use" rather than "own" because I cheat shamelessly with the microwave by just leaving it at -:--. Otherwise it would have both problems :-)

[lnr]

We have been known to do that with the microwave too - at least it doesn't do the things that some Microwaves do of starting at 12:00 when you turn it on and running the time from there! (I'm the person who resets the microwave and oven clocks in the kitchens of holiday cottages because they drive me up the wall).

The big radio signal wall clock in the living room seems really bad at initial syncing when you replace the batteries unless you leave it by the window for a while, but better at doing the clock changes, I have no idea why.

We could let Matthew use his tablet as a clock, but then he'd never put it down and go to sleep ;)

[simont]

really bad at initial syncing when you replace the batteries unless you leave it by the window for a while, but better at doing the clock changes, I have no idea why

I read up on the MSF radio protocol once. If I remember rightly, it goes something like: there's a pulse per second, with three different pulse lengths (1/10s, 1/5s, 1/2s). One of those lengths is used to indicate the start of the minute, and the other two are used in a binary pattern during the rest of the minute. So you get 59 bits of information, which is organised as a broken-down time (separate y,m,d,h,m,s fields) plus a couple of extra bits including "daylight saving?". That's why the clock has to listen for a minute or two (best case) before even knowing what to set itself to.

So I could imagine that you might be able to pick up DST changes and also keep the clock basically right using only two successfully received bits – the one at hh:mm:00 to determine the sync, and then the DST bit itself once you know when to expect it. Whereas to set the clock from cold you probably aren't satisfied unless you've successfully received a full minute of believable signal.

But I also feel as if that's more software sophistication than is perhaps plausible given the price and volume at which these clocks are sold!

[lnr]

It's possible I am just incredibly impatient when I put new batteries in, and it might be fine on the wall, just slower than I expect :)

[celestialweasel]

Ironically I turned back the central heating manually Saturday night, then it did it again itself. It must know the algorithm.
The microwave is high tech and did it itself somehow, the oven isn't and didn't.
I haven't looked at the car yet but that is weird and glitchy, I assume it is picking it up from the radio (RDS, the pointless traffic data stuff we never use or DAB?)

[lnr]

The bike computer is morally equivalent to the clock in the car for us :)

[sphyg]

Mine and E's dumbphones and our two analogue house clocks. At least I didn't fall off the chair this time!