TruePosition on the Arduino
Good evening all,
There is a saying: "a man with one watch knows the time, a man with two
is never sure." Clearly, this man wasn't a timenut and didn't have GPS. ;)
I've been working on the Arduino code for the TruePosition boards that
quite a few of us have bought from the e-place.
It's my first real foray into both Arduino and the C language. (About a
million years ago I was reasonably competent with FORTRAN...the 1977
version...) It's mostly working - I can receive and display pretty much
everything that comes out of the unit minus a few parameters. I can
display it all on three pages on a 4 line by 20 character I2C display.
Currently, the pages are selected by grounding out one of two pins, or
having nothing grounded. Eventually, I'm going to change this so that
it changes display pages when a button is pressed. I don't have
lat/long display yet, nor can I handle doing a survey, but those are coming.
My code probably would make a real programmer vomit, but hey, it works. :)
Back to the man with multiple watches. I was having a very frustrating
issue with my TruePosition and Arduino code being one second behind my
other sources of time. I went round and round, trying to figure out why
the TruePosition thru the Arduino was a second slow. In the end, it
turns out that it wasn't slow...it was correct...but that my other
sources of time have errors.
I finally proved this to myself by firing up an old Trimble Lassen LP
GPS board unit equipped with a 1PPS tick light and serial output...and
it was clear that it matched the TruePosition after correcting for the
fact that my TruePosition / Arduino code only updates the display when
1PPS is asserted high...but that the Lassen LP displays the serial
message before it becomes valid at the next 1PPS tick.
I was slightly embarrassed...I should have known that the other sources
of time all had sources of error beyond my control. I should have
trusted the TruePosition as being the purest, least complicated, and the
path I knew the most about between GPS and my eyeballs.
So for a while...the statement was true. With my multiple sources of
time...I really didn't know the time. But it was also untrue, as when I
got agreement between two very "pure" sources of time, I knew everything
else was wrong. ;)
I'm getting to the point that once I've got the button logic working,
I'll send out my source to anyone who wants to take a look at it or use
it. I will stipulate one condition - you can't make too much fun of how
poorly programmed it is. ;)
thanks much and 73,
ben, kd5byb
Ben:
Be careful.
Most GPS receivers send out the serial message after the tick, that tells
you what the time of the tick was.
Read the manual.
If you want to drive a clock display with a GPS, you pretty much have to
have an independent time system that advances on the tick, then validate it
when the serial message shows up.
--- Graham / KE9H
==
On Tue, Jun 6, 2017 at 6:46 PM, Ben Hall kd5byb@gmail.com wrote:
Good evening all,
There is a saying: "a man with one watch knows the time, a man with two is
never sure." Clearly, this man wasn't a timenut and didn't have GPS. ;)
I've been working on the Arduino code for the TruePosition boards that
quite a few of us have bought from the e-place.
It's my first real foray into both Arduino and the C language. (About a
million years ago I was reasonably competent with FORTRAN...the 1977
version...) It's mostly working - I can receive and display pretty much
everything that comes out of the unit minus a few parameters. I can
display it all on three pages on a 4 line by 20 character I2C display.
Currently, the pages are selected by grounding out one of two pins, or
having nothing grounded. Eventually, I'm going to change this so that it
changes display pages when a button is pressed. I don't have lat/long
display yet, nor can I handle doing a survey, but those are coming.
My code probably would make a real programmer vomit, but hey, it works. :)
Back to the man with multiple watches. I was having a very frustrating
issue with my TruePosition and Arduino code being one second behind my
other sources of time. I went round and round, trying to figure out why
the TruePosition thru the Arduino was a second slow. In the end, it turns
out that it wasn't slow...it was correct...but that my other sources of
time have errors.
I finally proved this to myself by firing up an old Trimble Lassen LP GPS
board unit equipped with a 1PPS tick light and serial output...and it was
clear that it matched the TruePosition after correcting for the fact that
my TruePosition / Arduino code only updates the display when 1PPS is
asserted high...but that the Lassen LP displays the serial message before
it becomes valid at the next 1PPS tick.
I was slightly embarrassed...I should have known that the other sources of
time all had sources of error beyond my control. I should have trusted the
TruePosition as being the purest, least complicated, and the path I knew
the most about between GPS and my eyeballs.
So for a while...the statement was true. With my multiple sources of
time...I really didn't know the time. But it was also untrue, as when I
got agreement between two very "pure" sources of time, I knew everything
else was wrong. ;)
I'm getting to the point that once I've got the button logic working, I'll
send out my source to anyone who wants to take a look at it or use it. I
will stipulate one condition - you can't make too much fun of how poorly
programmed it is. ;)
thanks much and 73,
ben, kd5byb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/m
ailman/listinfo/time-nuts
and follow the instructions there.
Hi
Calibrating your GPS pulse ambiguity is one of the all time great reasons to get a
WWVB based wall clock !!!
Bob
On Jun 6, 2017, at 8:38 PM, Graham / KE9H ke9h.graham@gmail.com wrote:
Ben:
Be careful.
Most GPS receivers send out the serial message after the tick, that tells
you what the time of the tick was.
Read the manual.
If you want to drive a clock display with a GPS, you pretty much have to
have an independent time system that advances on the tick, then validate it
when the serial message shows up.
--- Graham / KE9H
==
On Tue, Jun 6, 2017 at 6:46 PM, Ben Hall kd5byb@gmail.com wrote:
Good evening all,
There is a saying: "a man with one watch knows the time, a man with two is
never sure." Clearly, this man wasn't a timenut and didn't have GPS. ;)
I've been working on the Arduino code for the TruePosition boards that
quite a few of us have bought from the e-place.
It's my first real foray into both Arduino and the C language. (About a
million years ago I was reasonably competent with FORTRAN...the 1977
version...) It's mostly working - I can receive and display pretty much
everything that comes out of the unit minus a few parameters. I can
display it all on three pages on a 4 line by 20 character I2C display.
Currently, the pages are selected by grounding out one of two pins, or
having nothing grounded. Eventually, I'm going to change this so that it
changes display pages when a button is pressed. I don't have lat/long
display yet, nor can I handle doing a survey, but those are coming.
My code probably would make a real programmer vomit, but hey, it works. :)
Back to the man with multiple watches. I was having a very frustrating
issue with my TruePosition and Arduino code being one second behind my
other sources of time. I went round and round, trying to figure out why
the TruePosition thru the Arduino was a second slow. In the end, it turns
out that it wasn't slow...it was correct...but that my other sources of
time have errors.
I finally proved this to myself by firing up an old Trimble Lassen LP GPS
board unit equipped with a 1PPS tick light and serial output...and it was
clear that it matched the TruePosition after correcting for the fact that
my TruePosition / Arduino code only updates the display when 1PPS is
asserted high...but that the Lassen LP displays the serial message before
it becomes valid at the next 1PPS tick.
I was slightly embarrassed...I should have known that the other sources of
time all had sources of error beyond my control. I should have trusted the
TruePosition as being the purest, least complicated, and the path I knew
the most about between GPS and my eyeballs.
So for a while...the statement was true. With my multiple sources of
time...I really didn't know the time. But it was also untrue, as when I
got agreement between two very "pure" sources of time, I knew everything
else was wrong. ;)
I'm getting to the point that once I've got the button logic working, I'll
send out my source to anyone who wants to take a look at it or use it. I
will stipulate one condition - you can't make too much fun of how poorly
programmed it is. ;)
thanks much and 73,
ben, kd5byb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/m
ailman/listinfo/time-nuts
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and follow the instructions there.
This is an update to discussions off list with Ben and Chris regarding using
the two line, 16 character display with the Packrats software on the Arduino
to control the TruePosition GPS board.
First, the ebay seller still has a few boards left and seems to take offers
of $40 for them.
Second, the display used with the Packrats software must use the I2C address
of 0x3F to work. The display needs to use the PCF8574AT I2C I/O expander
chip and not the PCF8574T. The later chip addresses between 0x20 to 0x27 and
will not work with this software.
Third, I picked up some of the "A" chips on ebay and they were marked as A
chips but addressed wrong. If you are going to change out this expander
chip, get them from someone like Mouser.
Next step is to find a suitable housing for this assembly.
Thanks all,
Tom
----- Original Message -----
From: "Ben Hall" kd5byb@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Tuesday, June 06, 2017 7:46 PM
Subject: [time-nuts] TruePosition on the Arduino
Good evening all,
There is a saying: "a man with one watch knows the time, a man with two is
never sure." Clearly, this man wasn't a timenut and didn't have GPS. ;)
I've been working on the Arduino code for the TruePosition boards that
quite a few of us have bought from the e-place.
It's my first real foray into both Arduino and the C language. (About a
million years ago I was reasonably competent with FORTRAN...the 1977
version...) It's mostly working - I can receive and display pretty much
everything that comes out of the unit minus a few parameters. I can
display it all on three pages on a 4 line by 20 character I2C display.
Currently, the pages are selected by grounding out one of two pins, or
having nothing grounded. Eventually, I'm going to change this so that it
changes display pages when a button is pressed. I don't have lat/long
display yet, nor can I handle doing a survey, but those are coming.
My code probably would make a real programmer vomit, but hey, it works.
:)
Back to the man with multiple watches. I was having a very frustrating
issue with my TruePosition and Arduino code being one second behind my
other sources of time. I went round and round, trying to figure out why
the TruePosition thru the Arduino was a second slow. In the end, it turns
out that it wasn't slow...it was correct...but that my other sources of
time have errors.
I finally proved this to myself by firing up an old Trimble Lassen LP GPS
board unit equipped with a 1PPS tick light and serial output...and it was
clear that it matched the TruePosition after correcting for the fact that
my TruePosition / Arduino code only updates the display when 1PPS is
asserted high...but that the Lassen LP displays the serial message before
it becomes valid at the next 1PPS tick.
I was slightly embarrassed...I should have known that the other sources of
time all had sources of error beyond my control. I should have trusted
the TruePosition as being the purest, least complicated, and the path I
knew the most about between GPS and my eyeballs.
So for a while...the statement was true. With my multiple sources of
time...I really didn't know the time. But it was also untrue, as when I
got agreement between two very "pure" sources of time, I knew everything
else was wrong. ;)
I'm getting to the point that once I've got the button logic working, I'll
send out my source to anyone who wants to take a look at it or use it. I
will stipulate one condition - you can't make too much fun of how poorly
programmed it is. ;)
thanks much and 73,
ben, kd5byb
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.
Maybe I'm missing something, but Arduino programs are usually
distributed as source code. If this is the case, the I2C address of the
display should be not a problem. If the problem is due to the display
library used, you can use another library that can be initialized with
the right address.
I'm curious about the real problem.
Regards,
Ignacio, EB4APL
El 26/06/2017 a las 2:29, Tom Miller escribió:
This is an update to discussions off list with Ben and Chris regarding
using the two line, 16 character display with the Packrats software on
the Arduino to control the TruePosition GPS board.
First, the ebay seller still has a few boards left and seems to take
offers of $40 for them.
Second, the display used with the Packrats software must use the I2C
address of 0x3F to work. The display needs to use the PCF8574AT I2C
I/O expander chip and not the PCF8574T. The later chip addresses
between 0x20 to 0x27 and will not work with this software.
Third, I picked up some of the "A" chips on ebay and they were marked
as A chips but addressed wrong. If you are going to change out this
expander chip, get them from someone like Mouser.
Next step is to find a suitable housing for this assembly.
Thanks all,
Tom
----- Original Message ----- From: "Ben Hall" kd5byb@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Tuesday, June 06, 2017 7:46 PM
Subject: [time-nuts] TruePosition on the Arduino
Good evening all,
There is a saying: "a man with one watch knows the time, a man with
two is never sure." Clearly, this man wasn't a timenut and didn't
have GPS. ;)
I've been working on the Arduino code for the TruePosition boards
that quite a few of us have bought from the e-place.
It's my first real foray into both Arduino and the C language. (About
a million years ago I was reasonably competent with FORTRAN...the
1977 version...) It's mostly working - I can receive and display
pretty much everything that comes out of the unit minus a few
parameters. I can display it all on three pages on a 4 line by 20
character I2C display. Currently, the pages are selected by grounding
out one of two pins, or having nothing grounded. Eventually, I'm
going to change this so that it changes display pages when a button
is pressed. I don't have lat/long display yet, nor can I handle
doing a survey, but those are coming.
My code probably would make a real programmer vomit, but hey, it
works. :)
Back to the man with multiple watches. I was having a very
frustrating issue with my TruePosition and Arduino code being one
second behind my other sources of time. I went round and round,
trying to figure out why the TruePosition thru the Arduino was a
second slow. In the end, it turns out that it wasn't slow...it was
correct...but that my other sources of time have errors.
I finally proved this to myself by firing up an old Trimble Lassen LP
GPS board unit equipped with a 1PPS tick light and serial
output...and it was clear that it matched the TruePosition after
correcting for the fact that my TruePosition / Arduino code only
updates the display when 1PPS is asserted high...but that the Lassen
LP displays the serial message before it becomes valid at the next
1PPS tick.
I was slightly embarrassed...I should have known that the other
sources of time all had sources of error beyond my control. I should
have trusted the TruePosition as being the purest, least complicated,
and the path I knew the most about between GPS and my eyeballs.
So for a while...the statement was true. With my multiple sources of
time...I really didn't know the time. But it was also untrue, as
when I got agreement between two very "pure" sources of time, I knew
everything else was wrong. ;)
I'm getting to the point that once I've got the button logic working,
I'll send out my source to anyone who wants to take a look at it or
use it. I will stipulate one condition - you can't make too much fun
of how poorly programmed it is. ;)
thanks much and 73,
ben, kd5byb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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To unsubscribe, go to
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and follow the instructions there.
We do not have the source code. Just two binary versions, one with the
display and one without.
Regards
----- Original Message -----
From: "EB4APL" eb4apl@gmail.com
To: time-nuts@febo.com
Sent: Sunday, June 25, 2017 9:05 PM
Subject: Re: [time-nuts] TruePosition on the Arduino
Maybe I'm missing something, but Arduino programs are usually
distributed as source code. If this is the case, the I2C address of the
display should be not a problem. If the problem is due to the display
library used, you can use another library that can be initialized with
the right address.
I'm curious about the real problem.
Regards,
Ignacio, EB4APL
El 26/06/2017 a las 2:29, Tom Miller escribió:
This is an update to discussions off list with Ben and Chris regarding
using the two line, 16 character display with the Packrats software on the
Arduino to control the TruePosition GPS board.
First, the ebay seller still has a few boards left and seems to take
offers of $40 for them.
Second, the display used with the Packrats software must use the I2C
address of 0x3F to work. The display needs to use the PCF8574AT I2C I/O
expander chip and not the PCF8574T. The later chip addresses between 0x20
to 0x27 and will not work with this software.
Third, I picked up some of the "A" chips on ebay and they were marked as A
chips but addressed wrong. If you are going to change out this expander
chip, get them from someone like Mouser.
Next step is to find a suitable housing for this assembly.
Thanks all,
Tom
----- Original Message ----- From: "Ben Hall" kd5byb@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Tuesday, June 06, 2017 7:46 PM
Subject: [time-nuts] TruePosition on the Arduino
Good evening all,
There is a saying: "a man with one watch knows the time, a man with two
is never sure." Clearly, this man wasn't a timenut and didn't have GPS.
;)
I've been working on the Arduino code for the TruePosition boards that
quite a few of us have bought from the e-place.
It's my first real foray into both Arduino and the C language. (About a
million years ago I was reasonably competent with FORTRAN...the 1977
version...) It's mostly working - I can receive and display pretty much
everything that comes out of the unit minus a few parameters. I can
display it all on three pages on a 4 line by 20 character I2C display.
Currently, the pages are selected by grounding out one of two pins, or
having nothing grounded. Eventually, I'm going to change this so that it
changes display pages when a button is pressed. I don't have lat/long
display yet, nor can I handle doing a survey, but those are coming.
My code probably would make a real programmer vomit, but hey, it works.
:)
Back to the man with multiple watches. I was having a very frustrating
issue with my TruePosition and Arduino code being one second behind my
other sources of time. I went round and round, trying to figure out why
the TruePosition thru the Arduino was a second slow. In the end, it
turns out that it wasn't slow...it was correct...but that my other
sources of time have errors.
I finally proved this to myself by firing up an old Trimble Lassen LP GPS
board unit equipped with a 1PPS tick light and serial output...and it was
clear that it matched the TruePosition after correcting for the fact that
my TruePosition / Arduino code only updates the display when 1PPS is
asserted high...but that the Lassen LP displays the serial message before
it becomes valid at the next 1PPS tick.
I was slightly embarrassed...I should have known that the other sources
of time all had sources of error beyond my control. I should have
trusted the TruePosition as being the purest, least complicated, and the
path I knew the most about between GPS and my eyeballs.
So for a while...the statement was true. With my multiple sources of
time...I really didn't know the time. But it was also untrue, as when I
got agreement between two very "pure" sources of time, I knew everything
else was wrong. ;)
I'm getting to the point that once I've got the button logic working,
I'll send out my source to anyone who wants to take a look at it or use
it. I will stipulate one condition - you can't make too much fun of how
poorly programmed it is. ;)
thanks much and 73,
ben, kd5byb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
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To unsubscribe, go to
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and follow the instructions there.