[time-nuts] GPS for Nixie Clock
time at patoka.org
Tue Jul 12 13:50:59 EDT 2016
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.
On 2016-07-12 12:01, Chris Albertson wrote:
> What kind of micro processor are you using to run the Nixie tube clock?
> that processor could run NTP you would not need GPS. But of course
> could always do both. GPS requires a view of the sky and maybe that
> not available in a multi story building unless near a window. NTP
> would be
> available any place there is WiFi. Even without network connection,
> is a good way to interface the GPS as it knows how to talk to most
> made. can handle GPS outages (like when the clock is moved away from a
> That said, you are likely not using a uP big enough to run NTP as a
> like that is about $40 vs. using a bare AVR chip for about $3. But
> 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
> 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
> 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
> If you are looking for a GPS for use indoors I think you don't care
> anything other then receiver sensitivity. Without that you have
> no signal. It is more important than a few less nanoseconds of
> in the time solution. So those ublox receivers look good. I'm
> to buy some for another application, mobile robots, I'll use GPS for
> level navigation and it would be nice if it still worked indoors
> On Sun, Jul 10, 2016 at 10:24 PM, Mark Sims <holrum at hotmail.com> wrote:
>> The Jupiter receiver defaults to Motorola output, but can be switched
>> 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
>> and a 1PPS signal. They are MUCH more sensitive and usually work
>> 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
>> 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
>> small enough to not be noticeable. Some receivers send the message
>> the 1PPS, others after it. You can compensate for the
>> in software.
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