[time-nuts] PI Zero W LED Desktop Clock with 10ths of Seconds / NTP disciplined

Tim Shoppa tshoppa at gmail.com
Sun Jul 2 08:27:34 EDT 2017


I have been thinking about doing similar with an ESP8266 controller (which
start around $2). All the other machines in my house are locked to GPS at
either stratum 1 or stratum 2 so there are plenty of local good time
sources.

The ESP8266 has 64K, WiFi and a IP stack but does not run a real operating
system or ntpd. It does have kind of a multithreading scripting executive
(LUA). I would "homebrew" my own time discipline and peer selection
algorithms using much simpler tools, rather than full-blown ntpd. Simply
asking a local computer for ntp time is straightforward enough, then I add
some local time and frequency discipline on top of that.

After all, real NTP a couple decades ago ran on Fuzzballs which were
PDP-11's. I think at first they just calculated time offset from the 60Hz
line clock (16ms granularity) but I also recall a millisecond tick crystal
clock they could do frequency discipline on? All that fit on a PDP-11
nicely so I ought to be able to get much of it into an ESP8266.

Tim N3QE

On Sat, Jul 1, 2017 at 9:45 PM, M. George <m.matthew.george at gmail.com>
wrote:

> I just finished an LED clock kit that can be found on hackaday.io by Nick
> Sayer.   Below is a link to a couple of one take videos
> <https://www.youtube.com/watch?v=cAXFDt3PBJg> I made of the clock.  It's a
> nice piece of eye candy.  I haven't see an LED clock kit like this that
> uses a lite distribution of Linux where you have a server for the clock
> running NTP.  The code that runs the clock is a C program that you compile
> and run when the OS boots up.  It's nice that the PI Zero W is wireless for
> the clock... where it looks like a regular desk clock, but for the time-nut
> you can ssh in and check things out and look at loopstats etc...an NTP
> driven desk clock with 10ths of seconds.
>
> YouTube Video <https://www.youtube.com/watch?v=cAXFDt3PBJg>:
> https://www.youtube.com/watch?v=cAXFDt3PBJg
>
> Pictures
> <http://www.nc7j.com/pa/main.php?cmd=album&var1=NG7M%
> 2FRaspberry+PI%2FPI+Zero+W%2FDesktop+NTP+Clock>
> : http://www.nc7j.com/pa/main.php?cmd=album&var1=NG7
> M%2FRaspberry+PI%2FPI+Zero+W%2FDesktop+NTP+Clock
>
> I have no connection to the creator of the project or reason to give the
> project a plug other than I had fun making the simple kit and setting up
> Raspbian Lite to drive the PI Zero W., The creator of the kit is Nick Sayer
> on hackaday.io
> <https://hackaday.io/project/20156-raspberry-pi-zero-w-desk-clock>, I
> suspect he might get a few more looks at this project now:
> https://hackaday.io/project/20156-raspberry-pi-zero-w-desk-clock
>
> Enjoy, Max NG7M
>
> --
> M. George
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