An analog clock with hands usually *never* shows the right time, unless it doesn't run, only then it shows the correct time twice a day.
And no, the internet time is not synced to an atomic clock, but to a network of atomic clocks around the world. Greets, Kiste Am Freitag, 23. April 2021, 11:40:30 MESZ hat vsurducan <[email protected]> Folgendes geschrieben: Eur, an analog clock which does tic-tac, shows accurate time twice per day. It does not need synch. :) The real question is how we do know that the network time is accurate indeed? It is synchronized with an atomic clock? :) best wishes, On Fri, Apr 23, 2021 at 12:31 PM [email protected] <[email protected]> wrote: > Hi > Thanks for all the information. > I have to read a lot. > Till then I buy a cheap timer in the shop on the corner. > Peter > > Op dinsdag 20 april 2021 om 09:45:10 UTC+2 schreef Eur van Andel: >> Hi Zet >> >> Olivier Seitz has said a lot of useful things about keeping time already. I >> can add that some PIC18Fs have hardware real time clocks, some even with >> support for a 32kHz watch crystal on special pins. This will be accurate to >> minutes per year. >> >> Keeping time is of no use without syncing. That also holds for calendars. >> Syncing is so important for agriculture that several ancient civilisations >> spent insane amounts of work erecting huge stones to sync their calendars >> with the orbit of the planet. >> >> If you want to sync your time, you need to connect to a network. I do this >> in several ways: >> >> - with an RN171 wifi module, which is end-of-life, so not recommended >> - with an ESP32 which is cheap but overkill >> - with a SIM800L GSM module, which needs a SIM card >> >> SIM cards with data prices of €0.01/MB can be bought for €10 at keepgo.com >> The SIM800L can be bought on AliExpress for €2 >> I wrote a library for the SIM800, which I can add to jallib if you are >> interested. The SIM800 is 2G only, so your country should still support >> that. Europe does. >> >> The mobile network knows both the time, the time zone and the local DST. >> (Daylight Savings Time) >> >> A low cost solution could be a local “Stonehenge” with a narrow slit and a >> small solar cell that gives a good signal in direct sunlight. This would >> require a fixed location for the hardware and an unobstructed view to (a >> part of) the southern sky. You will also have to do some astronomical >> calculations. The Druids in England did those 5000 years ago, without the >> internet, so that won’t be too hard. >> >> You will be on solar time and syncing with a calendar will be hard, next to >> impossible. So when the DST kicks in will be unknown. >> >> >> >>> On 19 Apr 2021, at 23:23:03, [email protected] <[email protected]> wrote: >>> >>> Does a library excist with timezone Amsterdam so the microprocessor can use >>> it to send an order to start or stop a device every day at the same time? >>> >> >> >> --- >> ir EE van Andel [email protected] http://www.fiwihex.nl >> Fiwihex B.V. Wierdensestraat 74, NL7604BK Almelo, Netherlands >> tel+31-653-286573 >> >> >> >> >> > > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/21a991c4-df5e-4db9-a69d-f58bfae43c94n%40googlegroups.com. > -- You received this message because you are subscribed to the Google Groups "jallib" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jallib/CAM%2Bj4qsTho1s-%3D_nve92Y2qnaRZx5-5orXG7gY1MVYCgg_6WEg%40mail.gmail.com. -- You received this message because you are subscribed to the Google Groups "jallib" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jallib/1191615495.236101.1619171287043%40mail.yahoo.com.
