[time-nuts] GPS for Nixie Clock

Chris Albertson albertson.chris at gmail.com
Wed Jul 13 13:01:36 EDT 2016

On Sun, Jul 10, 2016 at 8:55 PM, John Swenson <johnswenson1 at comcast.net>

> I'm thinking about converting a Nixie clock I built years ago into using
> GPS for the time base. No real NEED, just for fun.
> Which is better to use, the 1PPS or the 10KHz? I can easily go either way.
> The clock display just goes down to seconds so 1PPS would work. I could
> also re-clock the 1PPS with the 10KHz.

You have to use the 1PPS.  It is in phase with the UTC second.   Your
seconds display increments with every PPS pulse.    If you were to use
10KHz, how would you know which of those 10,000 pulses was the UTC second

The way it works with GPS is you first de-code the message from the serial
port and hold that data in some internal memory then wait for the PPS
pulse.  When the pulse happens you move the internal memory data to the
display.  I don't know what you'd do with 10KHz except divide it by 10,000
to create your own 1PPS but how to get it to "tick" on the exact UTC second?

If you were displaying tenths of seconds then you'd need the 10K output
(divided by 1,000) to drive a counter that gets reset to zero by the PPS.

Chris Albertson
Redondo Beach, California

More information about the time-nuts mailing list