> Some of the Arduinos (not sure about Mini 04 but I am suspicious) use > ceramic resonators rather than real crystals and thus may have extremely > poor frequency stability. See here > http://jorisvr.nl/arduino_frequency.html > for an example.
ah! Very intriguing material, those crystals. I wonder what happens in them that they start to tick(?) at precisely 16MHz for example. > Is there some reason you are using a 16.9344 MHz oscillator rather than > 16.0? The processor will probably work, but timing of Arduino functions > like millis() and software serial baud rates will be affected. Misread I guess :-| Like that time that I bought 20 max690 instead of max680 ics. sigh. > On Wed, Dec 10, 2014 at 2:19 PM, folkert <[email protected]> wrote: > > > > I'm experimenting a bit with time keeping. > > > For that I use cheap low power hardware like raspberry pies and > > > arduinos. > > > > Hi people, > > > > Thanks for all the replies! Took a bit to respond but I had the flu. > > > > My objective is, to get the best precision/accuracy possible with said > > hardware. > > > > The first step is preparing an arduino. I found one that has an easy to > > desolder crystal: > > > > http://upload.wikimedia.org/wikipedia/commons/thumb/0/04/Arduino_Mini.jpg/170px-Arduino_Mini.jpg > > Bought a couple of those and some of these: > > > > http://www.aliexpress.com/item/Precision-TCXO-square-wave-oscillator-TCXO-16-9344MHz-line-rectangle/1104200137.html > > > > While waiting for these and the parts for the schematics, I'm toying > > around with implementing ntp servers (well, sntp) for arduino. With > > lots of blinkenlights of course and with ethernet. Not trivial I can > > say. > > This is the jitter plot of a test where time is fed from an RTC module. > > I did not plot the drift but it is +/- 120 seconds in the 3.8 days I > > measured it. > > http://vps001.vanheusden.com/~folkert/aRTC.png > > > > > > Folkert van Heusden > > > > -- > > ---------------------------------------------------------------------- > > Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > > --Jim Harman > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. Folkert van Heusden -- Multitail est un outil permettant la visualisation de fichiers de journalisation et/ou le suivi de l'exécution de commandes. Filtrage, mise en couleur de mot-clé, fusions, visualisation de différences (diff-view), etc. http://www.vanheusden.com/multitail/ ---------------------------------------------------------------------- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
