| pmj | Posted: 1 Nov 2020, 02:30 AM |
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 Member Posts: 1 Joined: 1-November 20 |
Just noticed that my highly accurate GPS Precision clock is saying it's 21:28 pm on Sat Oct 31, here in Toronto, Canada when my Atomic Clock is still on Daylight Savings Time saying 22:28 pm. We don't officially roll back 1 hour until 2:00 am tomorrow Sunday Nov 1, 2020. So, my GPS clock has jumped ahead before the offical change. What gives? ------------- |
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| mit | Posted: 2 Nov 2020, 11:04 AM |
 yeah whatever Admin Posts: 566 Joined: 4-May 16 |
Hi, sorry about this. It's a problem with the way the clock operates. The clock will have changed DST mode at 1am UTC, instead of 2am local time. I originally wrote the code with only European timezones in mind, which all switch at 1am UTC. It will take me quite a long time to fix this because a substantial part of the code needs to be rewritten. I became aware of this problem a while ago, but at the last DST switchover literally no-one noticed (or at least, no-one said anything), so I wasn't sure if it was even worth the effort. This time, a total of three people noticed, out of over a hundred clocks affected. On the one hand, I want this clock to be exactly right, all the time. On the other hand, this will take several days to fix and I'm tempted to spend that time working on the Mark IV. Hopefully I will find the time and enthusiasm to update the firmware before the next switchover. ------------- |
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| mit | Posted: 8 Nov 2020, 09:13 PM |
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yeah whatever Admin Posts: 566 Joined: 4-May 16 |
OK, I have updated the firmware to switch DST mode at the right times. For North American timezones this wasn't as hard as I expected. While European timezones all switch at 1AM UTC, American time zones switch at 2AM local time (both forwards and backwards). This means adjacent timezones don't have consistent differences. But since they're all in the western hemisphere it's just a question of delaying the change by a few hours, effectively switching at 5AM UTC, or as much as 9AM UTC for PST/PDT, but crucially on the same day. For eastern hemisphere timezones, notably Australia and New Zealand, the change is way more difficult. Summertime starts at 2AM local time, and ends at 3AM local time. Because the offset is positive, this effectively means the switch happens the day before, in terms of UTC. The first sunday of the month can sometimes land on the first of the month, so sometimes the switchover doesn't even appear to be the same UTC month. After several hours of mashing the keyboard with my brain, I seem to have produced something that works. To fix your clock, you'll need to do a firmware update, there are instructions here. The hex files have all been updated. ------------- |
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| tekvax | Posted: 27 Nov 2020, 11:49 AM |
 Member Posts: 1 Joined: 27-November 20 |
Sorry, I'm sure this is the incorrect place to post this, but I didn't see a topic regarding the kits. Will or do you sell just the circuit boards for the precision clock? Cheers, Dan ------------- |
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| mit | Posted: 29 Nov 2020, 11:54 AM |
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yeah whatever Admin Posts: 566 Joined: 4-May 16 |
I have considered it, I also considered selling a minimal kit which would be just the circuit board, laser cut parts, and the microcontroller with firmware flashed. Quite a few people have ordered clock kits minus the 7-segment displays, as they wanted to use different colour digits. If you send me an email I'm happy to sell you just the PCB. Last edit by mit at 29 Nov 2020, 11:55 AM ------------- |
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