Re: [time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?
----Original message----
From : hmurray@megapathdsl.net
Date : 21/10/2017 - 7:49 am (GMTDT)
To : gem@rellim.com
Cc : time-nuts@febo.com, hmurray@megapathdsl.net
Subject : Re: [time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?
For under a $100 you could get a Raspberry Pi, a GPS HAT, and
connect your input to a GPIO pin. Configure ntpd to log the real
PPS and the input as another 'PPS'.
Is there an option to log all individual PPS events?
# ppswatch /dev/pps0
That's a way to log stuff, but I don't think it comes under "Configure ntpd".
I remember some option to log lots of stuff, but I don't remember the
details. It could have been in a driver. I couldn't find it in the man page
for the PPS driver.
[amazon]
Looks like $96 to me. You can save some if you buy in bulk,
You can save $7 if you get the starter package that has only Pi, SD card,
power, and case. (Many starter packages include stuff you probably don't
need and that raises the price. But maybe one has a HDMI adapter. I didn't
look.)
Beware of using normal USB cables and/or normal USB power supplies. The Pi
is not happy with low voltage. The drop in a USB cable can be significant.
The setups intended for use with Pis normally have 5.1 or 5.25 volts and
heavier gage wire in the cable.
[display, kbd, mouse...]
Yeah, just for setup. Shall we include the price of the desk it sits and
the building it is in?
I'm willing to assume somebody has a table and a roof.
The display and such are not a problem if you have a PC you can borrow them
from. (You probably need a HDMI adapter.) But that doesn't work if all you
have is a laptop or smart phone.
I think most of my friends have PCs but I wouldn't be surprised if some of
them had a laptop and no PC.
If your PC is old enough, the keyboard and mouse may be PS2 rather than USB.
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FWIW, I’ve documented the whole R-Pi GPS NTP thing at https://hackaday.io/project/15137
As a disclaimer I will also say that I’m not even remotely the first. But what’s kind of nice is that I have a R-Pi desk clock display board that plays really well with a bolt-on GPS cap. In fact, I’ve got two of them in the NTP pool right now.
Sent from my iPhone
On Oct 21, 2017, at 7:50 AM, ROY PHILLIPS phill.r1@btinternet.com wrote:
----Original message----
From : hmurray@megapathdsl.net
Date : 21/10/2017 - 7:49 am (GMTDT)
To : gem@rellim.com
Cc : time-nuts@febo.com, hmurray@megapathdsl.net
Subject : Re: [time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?
For under a $100 you could get a Raspberry Pi, a GPS HAT, and
connect your input to a GPIO pin. Configure ntpd to log the real
PPS and the input as another 'PPS'.
Is there an option to log all individual PPS events?
ppswatch /dev/pps0
That's a way to log stuff, but I don't think it comes under "Configure ntpd".
I remember some option to log lots of stuff, but I don't remember the
details. It could have been in a driver. I couldn't find it in the man page
for the PPS driver.
[amazon]
Looks like $96 to me. You can save some if you buy in bulk,
You can save $7 if you get the starter package that has only Pi, SD card,
power, and case. (Many starter packages include stuff you probably don't
need and that raises the price. But maybe one has a HDMI adapter. I didn't
look.)
Beware of using normal USB cables and/or normal USB power supplies. The Pi
is not happy with low voltage. The drop in a USB cable can be significant.
The setups intended for use with Pis normally have 5.1 or 5.25 volts and
heavier gage wire in the cable.
[display, kbd, mouse...]
Yeah, just for setup. Shall we include the price of the desk it sits and
the building it is in?
I'm willing to assume somebody has a table and a roof.
The display and such are not a problem if you have a PC you can borrow them
from. (You probably need a HDMI adapter.) But that doesn't work if all you
have is a laptop or smart phone.
I think most of my friends have PCs but I wouldn't be surprised if some of
them had a laptop and no PC.
If your PC is old enough, the keyboard and mouse may be PS2 rather than USB.
--
These are my opinions. I hate spam.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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On 10/24/17 5:04 PM, Nick Sayer via time-nuts wrote:
FWIW, I’ve documented the whole R-Pi GPS NTP thing at https://hackaday.io/project/15137
As a disclaimer I will also say that I’m not even remotely the first. But what’s kind of nice is that I have a R-Pi desk clock display board that plays really well with a bolt-on GPS cap. In fact, I’ve got two of them in the NTP pool right now.
Sent from my iPhone
I've been connecting a Parallax NEO-7M to a beaglebone green..
GPS messages through the UART are easy.
pps less so.. I'm sure it's a matter of correctly configuring and
thrashing through the GPIO assignments with the capemgr - which
interestingly has had two substantial versions - most of the online
tutorials and material refer to the older one.
Hello Jim
We are using BeagleBone Black + GPS 1 pps etc in our time-transfer system
You can see the overlays in
https://github.com/openttp/openttp/tree/develop/software/system/device-tree-overlays
Best regards
Michael
On Wed, Oct 25, 2017 at 11:43 AM, jimlux jimlux@earthlink.net wrote:
On 10/24/17 5:04 PM, Nick Sayer via time-nuts wrote:
FWIW, I’ve documented the whole R-Pi GPS NTP thing at
https://hackaday.io/project/15137
As a disclaimer I will also say that I’m not even remotely the first. But
what’s kind of nice is that I have a R-Pi desk clock display board that
plays really well with a bolt-on GPS cap. In fact, I’ve got two of them in
the NTP pool right now.
Sent from my iPhone
I've been connecting a Parallax NEO-7M to a beaglebone green..
GPS messages through the UART are easy.
pps less so.. I'm sure it's a matter of correctly configuring and thrashing
through the GPIO assignments with the capemgr - which interestingly has had
two substantial versions - most of the online tutorials and material refer
to the older one.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi Michael,
You Wrote:
We are using BeagleBone Black + GPS 1 pps etc in our time-transfer system
You can see the overlays in
https://github.com/openttp/openttp/tree/develop/software/system/device-tree-overlays
Very interesting, I will have to clone the git repo, and have a closer
look.
I have my own 'fleet' of Beaglebone Blacks and Greens monitoring LORAN
and GPS. Working to add my small rubidiums and some LF and HF Clocks as
well. One day I will get the time to document the entire thing!
I am using the PRUSS to do Time Interval Measurements (details can be
found in the list archive), and feeding a PPS via TIMER4, and the highly
accurate timer that the Beaglebones have onboard.
Is there a particular reason you used the GPIO rather than TIMER4 ?
(If your google for Dan Drown DMTIMER, you will find the Linux Driver)
He also has coded up the TCLKIN pin, so that you can clock the
Beaglebone from an external reference, which also may be of interest.
(That bit I still need to do - I have the code enabled, just need to
plug a reference in to the Beaglebones!)
FreeBSD also has a driver for the TIMER4 input
Iain
Hi!
You could also look at NavSpark
(http://navspark.mybigcommerce.com/navspark-arduino-compatible-development-board-with-gps/). It
has a serial NMEA output, a PPS digital output AND a trigger pin for
timestamp capture.
Regards,
Edésio
On Wed, Oct 25, 2017 at 07:45:49AM +0100, Iain Young wrote:
Hi Michael,
You Wrote:
We are using BeagleBone Black + GPS 1 pps etc in our time-transfer system
You can see the overlays in
https://github.com/openttp/openttp/tree/develop/software/system/device-tree-overlays
Very interesting, I will have to clone the git repo, and have a closer
look.
I have my own 'fleet' of Beaglebone Blacks and Greens monitoring LORAN and
GPS. Working to add my small rubidiums and some LF and HF Clocks as
well. One day I will get the time to document the entire thing!
I am using the PRUSS to do Time Interval Measurements (details can be
found in the list archive), and feeding a PPS via TIMER4, and the highly
accurate timer that the Beaglebones have onboard.
Is there a particular reason you used the GPIO rather than TIMER4 ?
(If your google for Dan Drown DMTIMER, you will find the Linux Driver)
He also has coded up the TCLKIN pin, so that you can clock the
Beaglebone from an external reference, which also may be of interest.
(That bit I still need to do - I have the code enabled, just need to
plug a reference in to the Beaglebones!)
FreeBSD also has a driver for the TIMER4 input
Iain
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and follow the instructions there.
On 10/24/17 11:27 PM, Michael Wouters wrote:
Hello Jim
We are using BeagleBone Black + GPS 1 pps etc in our time-transfer system
You can see the overlays in
https://github.com/openttp/openttp/tree/develop/software/system/device-tree-overlays
Best regards
Michael
Tnx, I think my signal is coming through ok - if I look at
/sys/class/gpio/gpio66, I can see the value changing when I connect the
pin to +3 or 0V.
It's just not getting to the pps kernel driver -
No "assert" timestamp from /sys/class/pps/pps0/assert (or ppstest)