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mitxela / PrecisionClock-Hardware

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Use UTC instead of GMT #1

Open ad-si opened 4 years ago

ad-si commented 4 years ago

The term GMT is ambiguous as it sometimes means UT1 and sometimes UTC. Wikipedia therefore recommends: " The term GMT should not thus be used for certain technical purposes requiring precision." Quite unfitting for a project which is subtitled "Perfecting the pursuit of precision", right? 😉

mitxela commented 4 years ago

I think you may have misunderstood. At least one site has promoted the clock with the description "Can switch between UTC and a timezone of your choice" - this is not the case.

The two indicators in the middle of the clock describe the timezone, which changes during daylight saving time. The top light is Winter time and the bottom light is Summer time, always. For New York, the labels are EST and EDT. In the case of UK/London, those two labels are GMT and BST. The UK switches between GMT and BST, not UTC and BST.

A few of the clocks I've shipped have been labelled "UTC / UTC+1" upon request, but as far as I'm concerned GMT unambiguously refers to UTC+0 in this context. BST is defined as UTC+1, not UT1+1.

ad-si commented 4 years ago

The UK switches between GMT and BST, not UTC and BST

Uh, interesting interpretation. But I don't think I understand what this is supposed to imply? I'd say UK switches between UTC and BST, you just often hear the term GMT, because people haven't caught up yet that the term GMT has been replaced by the term UTC (due to its ambiguity).

A few of the clocks I've shipped have been labelled "UTC / UTC+1" upon request, but as far as I'm concerned GMT unambiguously refers to UTC+0 in this context. BST is defined as UTC+1, not UT1+1.

I'm thinking about buying one, but I'd prefer one without any label. Would this be possible? I've been switching all my electronic devices to UTC years ago and I've never looked back 😁(well except every time I have to use the Deutsche Bahn (German railway company) app. It has no notion of timezones and assumes that the local time on the cell phone is Germany's time 🤦‍♂️)

mitxela commented 4 years ago

It's confusing because GMT has such a long history and has meant different things in the past, but GMT now refers to a timezone. UTC is a time standard, not a timezone.

https://www.timeanddate.com/time/gmt-utc-time.html

I'm thinking about buying one, but I'd prefer one without any label. Would this be possible?

Sure, the labels are laser-etched on demand so it can say whatever you like. I've sold a few which were set (and labelled as) permanently UTC.

You could even have a capital T in the middle to conform to ISO8601, but it might take some fiddling with the LED positions to light up evenly.

ad-si commented 4 years ago

GMT now refers to a timezone.

timeanddate.com and some other websites make this claim without any references. Timezone abbreviations don't even seem to be standardized as tz uses the Europe/London format. And others beg to differ: https://stackoverflow.com/a/53909040/1850340

At any rate, I feel like the default should be UTC and UTC+1 or +00 and +01. That's a worthy labeling for a precision clock 😄.

You could even have a capital T in the middle to conform to ISO8601

If it wouldn't hurt readability so badly, I'd be all in 😂.

I'll be contemplating a few more days if I really want to solder the whole thing (the last time I tried to solder a kit, I left it in an unrepairable state 🙈), but this just feels like a must have 😋