David, Your raspberry-pi NTP clock is very cool.
I have put together something along the same line but is in reality just a network connected NTP disciplined clock display using an Arduino and a typical 16x2 LCD housed in a small project box. The Arduino has a network shield and get's it power from a USB port although it could be powered by a battery or wall wart type of supply. When it starts, the device attempts to get an IP address using DHCP. Once that is sorted it attempts to sync to my local GPS disciplined NTP server, then sets and displays it's time. It resyncs every some value between 15 and 30 minutes with the NTP server. If ever my local NTP server can't be found, it will attempt to sync to an outside NTP server on the internet. It keeps pretty good time, not "time nuts" level but is always within a few tenths of a second which is suitable for it's intended purpose. Basic time keeping of the Arduino uses it's 16MHz crystal clock and there is some provision for adjusting in code which I have done to improve it's time keeping. I am toying with the idea of adding a 1 PPS input but just haven't gotten round to it yet. All the bits and pieces of the code was copied from existing projects and libraries it being just a matter of finding the appropriate bits and pieces, putting them together and making changes in a few places to improve it's time keeping. It was a fun project to put together and has proven so useful in my lab that I will probably put together a couple more. Cheers, Graham ve3gtc =================================== Max, I see similar things here. I've always put it down to relatively poor circuitry in the radio clock, which is why I built my NTP-controlled wall clock! http://www.satsignal.eu/raspberry-pi/DigitalClock.html One radio clock is below. That particular MSF clock is actually not too bad - visibly it's in sync with the NTP clock (which itself is within a few microseconds of GPS time). 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: [email protected] . _______________________________________________ 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.
