Quote from: oliverb on Dec 05, 2013, 08:46 amQuoteit transpires we have no LF time transmitter in AustraliaWhat about using a GPS module instead? I think it will be my next project.How about both, so you can compare the results... :-)
Quoteit transpires we have no LF time transmitter in AustraliaWhat about using a GPS module instead? I think it will be my next project.
it transpires we have no LF time transmitter in Australia
I think in the long run they are both 100% . I don't know about GPS but DCF77 only updates once a minute on a perfect signal for the other time your are relying on the Arduino for timing.
My clock looses a second around 6 or 7 times a day (it always corrects itself) so I presume using the Arduino for a clock without any external correction is not a good idea.
I would expect 1 second in 2 weeks on a properly adjusted quartz clock in a reasonably stable temperature. Maybe I could add a trimmer to the Arduino crystal ?
I think it's the crystal that is the problem quartz clocks use a 32.768Khz crystal. You just divide by 2 15 times to get 1 second. 16mhz on the Arduino divided by 2 24 times gives 0.95 of a second. Maybe there are other value crystals that will work?
I notice there are loads of Real Time Clocks for Arduino they all seem to have crystals of 32.768kHz. Is this what they do just keep the time in sync?