Hi Ignacio
Your mention of the lights control had me confused for a minute, probably
not that difficult these days:-), because I do remember seeing that so was
wondering if the GPSTM tool had worked for me at one time after all.
However, a search through the various trimble programs
Whoopswill now write 1000 times...I must pay more attention:-)
I see you've already tried Tboltmon, so I presume there must be a bit more
to GPSTM monitor than is obvious from my quick glimpses before it crashes.
Let's see if it will run under Win98..
Regards
Nigel
GM8PZR
On Sat, Jan 18, 2014 at 11:14 PM, David J Taylor
david-tay...@blueyonder.co.uk wrote:
Are you perhaps thinking of sidereal time, Chris?
Either way, the difference is within the limits of the basic tin wind-up
alarm clock. A quality wrist watch would not work because it is to good
and
I wonder if you really need a special clock? Can't you adjust a normal
spring driven clock to run fast (or is it slow?) by about 1/3 of a percent
(one day per year)? This should be within the range of adjustment.
Chris,
When you mention 1/3 percent, you're thinking sidereal time, which is a
To Jim Lux. After you get it working, would you consider putting the details
online, or selling as a kit?
P Nielsen
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Gosh, Spring Wound would be hard pressed for even sidereal time. I know
I can't do that with my Atmos which is a definite step up from spring.
Lee
- Original Message -
From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
On Sat, Jan 18, 2014 at 10:09 PM, David J Taylor
david-tay...@blueyonder.co.uk wrote:
I am looking for a physical clock (not software) that will indicate local
solar time. IOW when the sun is at its highest point, the clock would
reliably read 12:00 throughout the year.
Is there a
Hi
Even a small PIC has room for a fairly large table. Rather than dealing with
leap years outside the table, just make it 4 years long rather than one year.
If you are trying to deal with 15 minutes, the table could get to 0.1 second
with two bytes per entry. It would fit in 3K bytes. It
/tvb wrote:
Solar time, on the other hand, is continuously variable in rate (and
phase) throughout the whole year. A microprocessor implementation of
solar time also needs to know calendar date, time, and longitude. A
4800 baud GPS NMEA stream input would be a convenient way to obtain
this
Hi
You could do the time / date thing with a WWVB (or similar) receiver. There are
a lot of cheap clocks (and kits) that work that way. The only thing you would
need past that is location. Any mechanical implementation would have the same
constraint.
Bob
On Jan 19, 2014, at 9:32 AM, Charles
Hi Bob,
On 01/19/2014 04:26 PM, Bob Camp wrote:
Hi
You could do the time / date thing with a WWVB (or similar) receiver. There are
a lot of cheap clocks (and kits) that work that way. The only thing you would
need past that is location. Any mechanical implementation would have the same
In message 52dbff99.3060...@rubidium.dyndns.org, Magnus Danielson writes:
My feverish brain now cranks out that all we need is a electromechanical
WWVB receiver, thus no active electronic parts. That would be a nice
little challenge.
The main challenge is an antenna which delivers sufficient
On 1/19/14 2:00 AM, P Nielsen wrote:
To Jim Lux. After you get it working, would you consider putting the details
online, or selling as a kit?
Half coded.
I'll publish all the details..
It's pretty easy.. a Arduino, a clock, a wall wart to power it. I
haven't tried it yet (no clock to test
On 1/19/14 1:49 AM, Chris Albertson wrote:
On Sat, Jan 18, 2014 at 11:14 PM, David J Taylor
david-tay...@blueyonder.co.uk wrote:
Are you perhaps thinking of sidereal time, Chris?
Either way, the difference is within the limits of the basic tin wind-up
alarm clock. A quality wrist watch
The usual quartz clock that runs off of a AA cell is a little
trickier to drive than you might think. You need to feed
its stepper motor coil with an alternating +1.5V and -1.5V pulse.
The pulse follows the rising or trailing edge of a 1/2 Hz square
wave. I have driven them using a series
On 1/19/14 9:17 AM, Chuck Harris wrote:
The usual quartz clock that runs off of a AA cell is a little
trickier to drive than you might think. You need to feed
its stepper motor coil with an alternating +1.5V and -1.5V pulse.
The pulse follows the rising or trailing edge of a 1/2 Hz square
wave.
Chris,
Mechanical clocks that display local solar time have been built for over
a hundred fifty years. There are mechanical wristwatches that also do
the same thing and are currently available. They're extremely expensive
but are being constructed. The local solar time is usually presented
From: Jim Lux
Right now, the EOT is changing almost 30 seconds/day, which implies that
the clock could be some seconds off during part of the day (although
true at noon).
[]
30 seconds/day?
http://www.sundials.co.uk/pix/c/eot3.gif
from:
http://www.sundials.co.uk/equation.htm
Cheers,
Clockmakers have made equation of time clocks for centuries, but because of
their complexity, they are quite rare. Most of them use a kidney shaped cam to
move a lever to display the time difference from clock time and local solar
time. (note - The Longnow clock uses a three dimensional EOT
On 1/19/14 9:40 AM, David J Taylor wrote:
From: Jim Lux
Right now, the EOT is changing almost 30 seconds/day, which implies that
the clock could be some seconds off during part of the day (although
true at noon).
[]
30 seconds/day?
http://www.sundials.co.uk/pix/c/eot3.gif
from:
On 01/19/2014 05:46 PM, Poul-Henning Kamp wrote:
In message 52dbff99.3060...@rubidium.dyndns.org, Magnus Danielson writes:
My feverish brain now cranks out that all we need is a electromechanical
WWVB receiver, thus no active electronic parts. That would be a nice
little challenge.
The main
Given the relatively low currents needed by the clock
motor, and the relatively high currents that can be
sourced/sinked by the arduino, and the fact that the
motor winding is floating relative to the arduino,
one could probably connect the motor like this:
D0---SomeResistor--MOTOR-D1
Then,
Hi!
Taking a 10MHz signal from a rubidium clock to an external device it is better
to use 0.5-1Vrms sine wave or TTL? A 75 ohm coaxial cable will be used with
just 1 meter long. In any case the receiver will be made around a unbuffered
gate with self biasing (it seems that the 74AC type has
In message 52dc152f.6080...@rubidium.dyndns.org, Magnus Danielson writes:
Here we would need to do MSF or DCF77, both would be severly challenging
to do passively.
Not decoding wise. Once you have a robust signal, it's easy...
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
Hi
I’d bet that you can do some sort of simple fit to +/- 3 days from today and
get a reasonable estimate of the rate. Exactly what you would fit might vary
over the year.
Bob
On Jan 19, 2014, at 1:05 PM, Jim Lux jim...@earthlink.net wrote:
On 1/19/14 9:40 AM, David J Taylor wrote:
From:
Jim: I used a simple f/f, q and ~q and 180 ohm resistors. Could easily
be done with two ard outputs. needs 1/2 sec cycle. i just disconnected
the coils from the epoxied blob with the clock electronics. You can also
drive it backwards if it amuses. . .
Don
--
The power of accurate observation
On 1/19/14 10:11 AM, Chuck Harris wrote:
Given the relatively low currents needed by the clock
motor, and the relatively high currents that can be
sourced/sinked by the arduino, and the fact that the
motor winding is floating relative to the arduino,
one could probably connect the motor like
On 1/19/14 10:47 AM, Don Latham wrote:
Jim: I used a simple f/f, q and ~q and 180 ohm resistors. Could easily
be done with two ard outputs. needs 1/2 sec cycle. i just disconnected
the coils from the epoxied blob with the clock electronics. You can also
drive it backwards if it amuses. . .
Don
Yeah.. that *is* the challenge.
Use two outputs and make a sort of H bridge
Jim,
No problem.
1) equation of time:
See www.leapsecond.com/tools/eot1.c, source code that generates the equation of
time and its derivative. Sample output attached. You can see the time varies
from about -14
Hi
I’d put the table(s) in flash. You aren’t going to change it often enough to
matter in terms of re-flash cycles. They would all be pre-calculated for that
clock at that location, starting from today. In my approach this would be a
very application specific shoot of the code. The 18F24J10 is
On 1/19/14 11:21 AM, Tom Van Baak wrote:
Yeah.. that *is* the challenge.
Use two outputs and make a sort of H bridge
Jim,
No problem.
1) equation of time:
See www.leapsecond.com/tools/eot1.c, source code that generates the equation of time and
its derivative. Sample output attached. You
I tried that algorithm and it did not seem to agree all that well with more
sophisticated ones... This one seems to work better:
http://www.astronomycorner.net/games/analemma.c
--
See www.leapsecond.com/tools/eot1.c, source code that generates the equation of
time and its
So, Tom's EOT routine takes less than a millisecond to execute (in
double precision) on the Arduino..
So what I can probably do is call it every minute or hour to update the
rate for the next minute/hour.
Now I just have to figure out how to conveniently set the current
date/time (for now,
On 1/19/14 11:24 AM, Bob Camp wrote:
Hi
I’d put the table(s) in flash. You aren’t going to change it often enough to
matter in terms of re-flash cycles. They would all be pre-calculated for that
clock at that location, starting from today. In my approach this would be a
very application
What is the difference in rate between solar and UTC and how much does the
solar rate change from week to week?
I know the theory and to get it nearly perfect you'd need a computer. But
if your tolerance is only that it be good enough for a visual reference.
(remember he said __NO SOFTWARE__)
On Sun, Jan 19, 2014 at 6:32 AM, Charles Steinmetz csteinm...@yandex.comwrote:
The question I haven't seen answered is what error band is acceptable to
the OP. Mark has posted that it is not terribly difficult to get within
small fractional minutes if you start with GPS time and position
From: Jim Lux
http://www.wsanford.com/~wsanford/exo/sundials/equation_of_time.html
5 Jan 5.2 minutes
6 Jan 5.7 minutes
30 seconds in a day..
The total variation over the year is +/- 15 minutes, but the derivative
is a lot bigger at some times of the year (now)
My feverish brain now cranks out that all we need is a electromechanical
WWVB receiver, thus no active electronic parts. That would be a nice little
challenge.
That could work. I remember seeing an only World War II vintage teletype
machine. It would print test from an HF receiver. Given the
On 1/19/14 12:20 PM, David J Taylor wrote:
From: Jim Lux
http://www.wsanford.com/~wsanford/exo/sundials/equation_of_time.html
5 Jan 5.2 minutes
6 Jan 5.7 minutes
30 seconds in a day..
The total variation over the year is +/- 15 minutes, but the derivative
is a lot bigger at some times of
It turns out there's a handy Arduino library for time. And it will
ingest GPS or NTP, etc., as well as run off the internal clock.
One strategy, then, is:
Set the clock in the Arduino
then, periodically (once a minute or hour)
look up the date and time
calculate rate
On 14-01-19 03:20 PM, Chris Albertson wrote:
My feverish brain now cranks out that all we need is a electromechanical
WWVB receiver, thus no active electronic parts. That would be a nice little
challenge.
That could work. I remember seeing an only World War II vintage teletype
machine. It
So, periodically, one would need to reset both the analog clock AND the
Arduino clock to bring them back to proper alignment.
I suppose that periodically, one could compare number of ticks sent
with UTC + EOT offset and try to compensate (by dropping ticks or
adding them).
And then
I am really learning a lot by reading the current discussion. As for
accuracy, the clock was originally envisioned for non-scientific use.
Something within the budget and building capabilities of the home
enthusiast. A weekly deviation in seconds would seem tolerable. But I am
encouraged those
I'm pretty sure the arduino double precision routines are actually single
precision... at least they are in the standard AVR ports of GCC.
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I hope this thread dies here.
In a message dated 1/19/2014 13:22:10 Pacific Standard Time,
a...@comcast.net writes:
On 14-01-19 03:20 PM, Chris Albertson wrote:
My feverish brain now cranks out that all we need is a electromechanical
WWVB receiver, thus no active electronic parts. That
t...@leapsecond.com said:
If your project works ok for the earth clock, the next step is a
jaw-dropping array of 8 (9) clocks in a JPL lobby showing the differently
ticking solar time for each planet. Use 24h clocks for best results. They
can be had from www.clockkit.com, an excellent source
On 18 Jan, 2014, at 20:11 , Jim Lux jim...@earthlink.net wrote:
Just in case you want to build a clock with an Arduino..
http://jorisvr.nl/arduino_frequency.html
ADEV measurements, etc.
take home message.. absolute accuracy is a few kHz out of 16 MHz... probably
a 100 ppm crystal.
FWIW
If you take a cheap digital analog clock, remove the battery,
connect to the two coil connections, you can drive the clock with a
0.5 Hz square wave through the series combination of a capacitor and resistor.
Typical values are 100mfd and 200 ohms.
You need to select these values to get
On 1/19/14 1:51 PM, Tom Van Baak wrote:
So, periodically, one would need to reset both the analog clock AND the
Arduino clock to bring them back to proper alignment.
I suppose that periodically, one could compare number of ticks sent
with UTC + EOT offset and try to compensate (by dropping
Chris Albertson
Don't worry about fitting this inside a PIC, modern uPs have 32K of
storage, can be programmed in C++, have floating point math libraries
and
cost $5 shipped for one mounted to a PCB with supporting electronics.
If you Really want to show it, use a pendulum clock using an equation of
time cam to change the length?
Don
P Nielsen
I am really learning a lot by reading the current discussion. As for
accuracy, the clock was originally envisioned for non-scientific use.
Something within the budget and
At last, a use for all those devices with 2 second pulse output :-)
Don
Neville Michie
FWIW
If you take a cheap digital analog clock, remove the battery,
connect to the two coil connections, you can drive the clock with a
0.5 Hz square wave through the series combination of a capacitor and
And this lead me to a RTC module for $1.88 that will provide a time
that can be massaged with eq'n of time.
Speaking of RTC modules, I don't know which one you found, but I have some
of these on order for $2.29 each:
It is. Both double and float are 32-bits. Arduino uses the GCC AVR
compiler.
If you care a lot about precision you use integer math and do all your
calculations in integer units of milli or microseconds. If you try to keep
time in floats you are working with about four decimal digit
So, do you run the whole thing off 12V (which is what I'm going to do)
and a float charged battery OR do you do something clever like detect
when power is failing and save it in NV storage, then when you come back
up, you send a bunch of clock ticks real fast to catch up.
Use a high-res
On 1/19/14 3:58 PM, Chris Albertson wrote:
It is. Both double and float are 32-bits. Arduino uses the GCC AVR
compiler.
If you care a lot about precision you use integer math and do all your
calculations in integer units of milli or microseconds. If you try to keep
time in floats you are
Really, what it is is calculating the new 1pps divisor for the timer
driving ISR, which divides down from the clock rate of the Arduino.
The trick is for integer math is to never do or postpone division. So if
you have 1560 PPS per 1432 ticks (or whatever) the number is a rational
fraction of
On 1/19/14 4:10 PM, Tom Van Baak wrote:
So, do you run the whole thing off 12V (which is what I'm going to do)
and a float charged battery OR do you do something clever like detect
when power is failing and save it in NV storage, then when you come back
up, you send a bunch of clock ticks real
Hi
Rather than calculating the ppm offset, calculate the number of ticks until you
drop (or add) one tick. Your output pps can only be offset from the input pps
by an integer number of ticks anyway. The next decision would be - how big a
tick can you get away with? For a wall clock, 100 ms is
It is. Both double and float are 32-bits. Arduino uses the GCC AVR
compiler.
If you care a lot about precision you use integer math and do all your
calculations in integer units of milli or microseconds. If you try to keep
time in floats you are working with about four decimal digit
The EOT code that I linked to (http://www.astronomycorner.net/games/analemma.c)
and am using is interesting because it appears to be applicable to other
planets. It has parameters like the orbit
obliquity/eccentricity/perihelion/year length that can be changed. It also
does not make
An electro-mechanical RX for VLF.
http://www.wireless.org.uk/mechrx.htm
enjoy
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Hi:
I thought that noon was defined as the Sun crossing the local meridian.
So something like the Dent Dipleidoscope can be used to know the exact instant
when that happens.
This is different than standard time by the EOT.
http://www.prc68.com/I/Dent.shtml
It's not clear if the OP wants true
Oh well, 0230 is probably as good a time as any to call it quits for the
day:-)
I've now tried Win98 and even loaded Win95 on to an old laptop as that and
NT was what the GPSTM tool was originally intended to run under and it's
still not happy, so it does look to be a non starter, in more
Hi all,
Funny how this topic of the arduino time library comes around. Have been
following your conversations regarding the precise nature of arduino time
(gps time aware)
Is it possible to write (assuming the poor little creature would do it) a
piece of code, that given your lat/long, the time
Many years ago I saw some pictures in Sky and Telescope where some people
had mounted a camera in such a way as to not be disturbed from day to day
and taken an exposure of the sun at 12 noon local mean time every day of the
year all on the same photographic plate. At the end of the year upon
analemma not infinity. Excuse the analism please.
- Original Message -
From: Max Robinson
To: Discussion of precise time and frequency measurement
Sent: Sunday, January 19, 2014 10:36 PM
Subject: Re: [time-nuts] Local Solar Time Clock
Many years ago I saw some pictures in
Digital photography - use Photoshop ….
On Jan 19, 2014, at 10:49 PM, quartz55 quart...@hughes.net wrote:
analemma not infinity. Excuse the analism please.
- Original Message -
From: Max Robinson
To: Discussion of precise time and frequency measurement
Sent: Sunday, January
On 1/19/14 6:41 PM, Lizeth Norman wrote:
Hi all,
Funny how this topic of the arduino time library comes around. Have been
following your conversations regarding the precise nature of arduino time
(gps time aware)
Is it possible to write (assuming the poor little creature would do it) a
piece of
It's not clear if the OP wants true local time or the time at the center of
his time zone.
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
My original idea was to have 12 noon equate to the sun's highest position in
the sky at my locality, and
On 1/19/14 8:00 PM, P Nielsen wrote:
It's not clear if the OP wants true local time or the time at the center of
his time zone.
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
My original idea was to have 12 noon equate to the sun's
There is digital astronomy specific out there that will overlay/digitally add
multiple images, do filtering, enhance contrast, etc. It's just something I've
read about at this point. I haven't used it and couldn't point you to specific
software.
From:
m...@maxsmusicplace.com said:
had mounted a camera in such a way as to not be disturbed from day to day
and taken an exposure of the sun at 12 noon local mean time every day of the
year all on the same photographic plate. At the end of the year upon
development of the plate they had a nice
Hi all,
Funny how this topic of the arduino time library comes around. Have been
following your conversations regarding the precise nature of arduino time
(gps time aware)
Is it possible to write (assuming the poor little creature would do it) a
piece of code, that given your lat/long, the time
albertson.ch...@gmail.com said:
The trick is for integer math is to never do or postpone division. So if
you have 1560 PPS per 1432 ticks (or whatever) the number is a rational
fraction of 1560/1432 and you store it as two integer. The goals is to
always be exact. that at the end you need
On Sun, Jan 19, 2014 at 6:41 PM, Lizeth Norman normanliz...@gmail.comwrote:
Is it possible to write (assuming the poor little creature would do it) a
piece of code, that given your lat/long, the time and a two line element
set for an orbiting object, such as the ISS, that would give you the
From: Jim Lux
[]
To be honest, one of the interesting challenges is dealing with power
failures in these kinds of systems. The Arduino is not a low power
device..(at least not in the AA battery for 2 years sense).
[]
___
Jim,
For low-power, long
Chris,
Thanks for the info on the launchpad. Believe it or not, the problem isn't
power drain, it's keeping the electronics (most importantly the batteries)
at operating temperature when the outside air temperature is -30F or lower.
A thought was to use electric socks or handwarmers and modulate
Jim,
No need to point an antenna. Just know when the iss is visible. The arduino
will drive the modem, hence driving the radio.
Do follow you in regards to the matrix approach. Would have to take a
standard two line element set and do some number crunching. Shouldn't be
all that hard.
Norm n3ykf
We are probably saying the same thing, but I didn't think of it this way when
reading your description...
Correct, to maintain timekeeping accuracy the goal is not so much to avoid
division, but to pay attention to the remainder when division is used. You may
have noticed that many time
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