[time-nuts] Portable Time Standard

[Jim Harman]

For ease of programming and reasonably low power consumption I would look
into an Arduino.

There are libraries available to control the DS3231 and your choice of
displays. The Chronodot is a nice prototyping package for the 3231.
https://www.adafruit.com/product/255

On Wed, Mar 6, 2019 at 8:02 PM Joe Hobart <nova at npgcable.com> wrote:

> Hello Petr and others,
>
> Thank you for the suggestions.  I have several DS3231 modules running.  I
> was
> able to adjust one to 0.04 PPM fast, which is more than good enough for my
> requirement of one second a month (this is at a constant temperature, but
> these
> RTC chips are supposed to be temperature compensated).
>
> I can read and write the DS3231 registers with a Raspberry Pi.
> Unfortunately,
> the RPi kernel sends time to the RTC every 11 1/2 minutes.  This time is
> usually
> moderately accurate, but I have measured errors of up to 0.264 second,
> which is
> unacceptable.
>
> Does anyone have suggestions for a very low power controller and display
> for
> this RTC integrated circuit?  The DS3231 has a 1 Hz square wave output that
> could signal the controller to read and display the time and date from the
> DS3231.  The controller could sleep between updates, which would conserve
> batteries.
>
> Thanks again for all the suggestions,
> Joe
>
> By the way, the manufacturer of the high accuracy marine chronometer I was
> considering will not send specifications for other than 22 +/- 1 degree C.
>
>
> These DS3231 modules are a complete clock
>
>
>
> --

--Jim Harman