[time-nuts] PPS clock module

[Tim Shoppa]

Some of the 1970's era National Semiconductor clock modules and chips, you
could leave the 50/60Hz input unused and instead jam a PPS pulse into the
"colon blink" pin.

There were some commercial time display products into the 1990's that used
this and other NatSemi clock tricks. For example where I work we had
hundreds of public facing clocks that would jam-load 24 hour midnight
resets in for synchronization. 10 seconds before midnight we would jam load
midnight and hold it until midnight actually ticked over. On DST changes we
had to sync up to the next mornings time not the current time and once we
made the newspaper for accidentally closing an hour early that night :-)

Today - get an Arduino Nano clone ($3) and a 6-digit-7-segment module or
dot matrix module ($10).

Tim N3QE

On Sun, Jan 27, 2019 at 4:05 PM John Ackermann N8UR <jra at febo.com> wrote:

> I'm putting together a portable Rb standard and thought it would be nice
> to include a clock on the panel.  I probably haven't hit the magic
> search words, but I haven't found what I'm looking: a module (no
> enclosure) that is driven by an external PPS and shows at least HH:MM:SS
> in 24 hour format on a small LED or LCD display.
>
> I can whip something together with an Arduino, but rather than reinvent
> the wheel I thought I'd ask if anyone knows of something that's ready to
> go.
>
> Thanks,
> John
>
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