[lug] Time sync w/GPS or radio
jason at vallery.net
Thu May 15 15:41:31 MDT 2008
I'm a bit late to this thread, but I was working on a separate project
using GPS and came across an interesting product. Garmin makes a
"puck" GPS receiver that just has a serial cable output on it. It is
a fairly dumb device that when powered up generates a NMEA 0183 data
stream on the serial interface. For $70 you can't beat the price.
You can see it here:
If you look at the NMEA spec the data stream contains the UTC time.
It seems like it would be pretty trivial to write up a shell script
that monitors the serial interface and sets the clock based on the
incoming data stream.
I just ordered one and I can't wait to play with it.
On Thu, May 8, 2008 at 4:32 PM, George Sexton <gsexton at mhsoftware.com> wrote:
> I've been wanting a time receiver for a long time. In a previous life, I was
> a calibration technician so I've been fascinated with time and frequency
> standards for a long time. What's been killing me has been the price. It's
> tough for me to explain to my wife that I want to buy a $1500 GPS time
> receiver because I think it would be cool. It's neat to see the Beaglesoft
> one is much cheaper.
> I looked at the Radio Sync thing from the Beaglesoft folks, and it's nice at
> $220, but it's not directly supported by NTP. Someone would have to write a
> driver for it.
> I saw their GPS receiver is a Garmin GPS-16. For kicks, I went to Garmin's
> site and found the unit for $105.
> It looks like you would need to follow these instructions to create an
> RS-232 interface and power supply. There are also instructions on getting
> the PPS stuff working, which is essential for higher accuracy:
> I'm sure that even if you purchased the kit from Beaglesoft, you would have
> to do the kernel PPS steps on the URL.
> This would be a really cool project. I'm halfway handy with a soldering iron
> and I'm sure it wouldn't take much more than an hour to create the PCB.
> Lori Reed wrote:
>> IME, gps devices, at least hand held and pcmcia devices, have, at best,
>> problematical indoor reception. A bit of quick googling found this:
>> I'm sure there are others.
>> Just curious, what is the url for the UK vendor you reference?
>> Gary Hodges wrote:
>>> I have some remote machines w/o internet access. I get around that by
>>> dialing in a couple times a day, but I've never liked that solution. But
>>> what prompted me to start looking for a solution is... You all will love
>>> this... I have a machine on the net behind the firewall of a very large
>>> government organization where I'm not able to use a time server outside the
>>> network. And, get this, they don't keep the time set on their internal time
>>> In case anyone is interested, I got a price quote from that UK vendor
>>> this morning. $1590 for a GPS solution and $995 for a WWVB solution.
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> George Sexton
> MH Software, Inc.
> Voice: +1 303 438 9585
> URL: http://www.mhsoftware.com/
> Web Page: http://lug.boulder.co.us
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jason at vallery.net
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