Casio-F-91W die-shot

Post by [deleted] » Tue, Jan 03, 2023, 1:10 AM UTC

Tor3 wrote: post #25

vasqw wrote: post #12

I bought one of those recently and I was surprised by how inaccurate it was. It drifted like 15 seconds every month. From what I've been reading, that is normal, but I was surprised - with all the technological advances that we have it is odd to think that cheap timekeeping is not a solved problem yet! Also: how is the software of these watches without a CPU designed? Is it something like Verilog or whatever?

At around 1976-1977 I bought one of those fancy new LED wristwatches, where you pressed a button and the time lit up in red. Straight out of James Bond, as I recall. As I was studying electronics at the time I brought the watch to the lab and opened it and connected a frequency counter to the oscillator, you could clearly see the crystal and a little trimming pot (I don't remember by now if that was a pot or somethin…

Post by interfixus » Tue, Jan 03, 2023, 1:17 AM UTC

dbttdft wrote: post #162

interfixus wrote: post #112

Earlier quoted context omitted.

Absolutely, get a G-Shock. But get one which radiosyncs. Most phones (and PCs), although synced by internet, reliably lag between one and two seconds. My synced G-Shock is always correct to within better than one tenth of a second, that is, to the limit of observability. Solar powered, too, so it's just an utterly reliable black box. My favourite gadget by far.

> Most phones (and PCs), although synced by internet, reliably lag between one and two seconds. NTP isn't nearly that inaccurate.

Post by Maursault » Tue, Jan 03, 2023, 4:09 PM UTC

klodolph wrote: post #134

Maursault wrote: post #129

Earlier quoted context omitted.

> But was impressed when I learnt that there is no analog wristwatch that can match this accuracy Seiko 5 automatics apparently[1] can.[2] [1] https://www.watchuseek.com/threads/seiko-5-is-pretty-accurat... [2] https://qr.ae/prvf6L

According to the linked thread, the Seiko 5 is an order of magnitude worse… 5 seconds per day, versus 15 seconds per month for a quartz watch.

     After observing Seiko 5 SNK809 for 35 days, I can say I´m happy with accuracy.

     Overall, it has lost 25 seconds during this time.
     It lost most of it when it was sitting on table 2 times during observation. When kept on wrist, it hardly lost any...

Post by icybox » Tue, Jan 03, 2023, 9:40 PM UTC

TedDoesntTalk wrote: post #108

somat wrote: post #106

Earlier quoted context omitted.

Is it incandescent!? I would have expected an led, or at least a process improvement where it was replaced by an led.

It’s still an incandescent, unfortunately. If they changed it to an LED, it might be bright enough to be useful.