In addition, even MCU has not enough resources to handle TCP/IP, DHCP
and NTP, it is some solutions available to outsource it to dedicated
chips. I was using WIZ5100 (assembled as a modules) with great success.
Regards,
Vlad
On 2016-07-12 12:01, Chris Albertson wrote:
What kind of micro processor are you using to run the Nixie tube clock?
If
that processor could run NTP you would not need GPS. But of course
you
could always do both. GPS requires a view of the sky and maybe that
is
not available in a multi story building unless near a window. NTP
would be
available any place there is WiFi. Even without network connection,
NTP
is a good way to interface the GPS as it knows how to talk to most
GPSes
made. can handle GPS outages (like when the clock is moved away from a
window)
That said, you are likely not using a uP big enough to run NTP as a
setup
like that is about $40 vs. using a bare AVR chip for about $3. But
even
with the smaller uP you might think about having the chip keep it's own
internal time and using GPS to discipline that internal time, much like
the
way NTP works. Basically the uP has a flywheel and GPS regulates it's
speed. Let's you handle holdover gracefully.
If using NMEA sentences from GPS, remember that the NMEA standard
allows
those senates to come out at any time during the second to which they
apply. In other words the sentence itself can be up to almost a second
"off".
If you are looking for a GPS for use indoors I think you don't care
about
anything other then receiver sensitivity. Without that you have
nothing,
no signal. It is more important than a few less nanoseconds of
uncertainty
in the time solution. So those ublox receivers look good. I'm
looking
to buy some for another application, mobile robots, I'll use GPS for
gross
level navigation and it would be nice if it still worked indoors
On Sun, Jul 10, 2016 at 10:24 PM, Mark Sims <hol...@hotmail.com> wrote:
The Jupiter receiver defaults to Motorola output, but can be switched
to
Zodiac. It talks at 9600:8:N:1
Frankly, it is the wrong receiver to use, particularly with an indoor
antenna. I would go with a modern GPS receiver with standard NMEA
output
and a 1PPS signal. They are MUCH more sensitive and usually work
indoors
and can be had for dirt cheap. Most have an on-board ceramic patch
antenna. Ublox receivers seem to work well indoors.
NAVSPARK makes a tiny little GPS board with 1PPS output. 6 for $36 or
one
free for $10 shipping (no antenna supplied, has a U.FL connector). It
speaks NMEA at 115,200:8:N:1 or can be setup for 9600 baud.
The delay between message and 1PPS is receiver dependent. Usually it
is
small enough to not be noticeable. Some receivers send the message
before
the 1PPS, others after it. You can compensate for the
differences/delays
in software.
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V.P.
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