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
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and
Sent: Sunday, January 19, 2014 6:25 AM
Subject: Re: [time-nuts] Local Solar Time Clock
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
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,
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
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
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
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 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
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
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:
An electro-mechanical RX for VLF.
http://www.wireless.org.uk/mechrx.htm
enjoy
___
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:
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
19, 2014 7:35 AM
Subject: Re: [time-nuts] Local Solar Time Clock
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
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
19, 2014 10:36 PM
Subject: Re: [time-nuts] Local Solar Time Clock
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
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
: quartz55 quart...@hughes.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sunday, January 19, 2014 9:49 PM
Subject: Re: [time-nuts] Local Solar Time Clock
analemma not infinity. Excuse the analism please.
- Original Message -
From: Max Robinson
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
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 commercial product or kit available for this?
Thank you for any suggestions.
P Nielsen
On 1/18/14 2:25 PM, P Nielsen 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.
So it needs to take into account the equation of time?
there's
VCR's were well known to reliably read 12:00 throughout the year...
Do you want to make or buy? Using a microprocessor, it's easy to drive a
stepper-motor based wall clock at slight offsets from true 32 kHz or 1 Hz rate.
Converting UTC/1PPS to solar rate and time for your given location and
On 1/18/14 2:25 PM, P Nielsen 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 commercial product or kit available for this?
Small brass cannon. Use a small telescope pointed at the sun at transit, with
the output side focused on the fuse.
Loud bang ,.. it's 12:00 o'clock.
-- FL
On Saturday, January 18, 2014 4:23 PM, Tom Van Baak (lab) t...@leapsecond.com
wrote:
VCR's were well known to reliably read 12:00
HI
If noon is the point you are concerned about, and it’s a fixed location, a
fairly simple set of tables in a micro should do the trick. Past that it’s a
selection for the time base, anything from a 555 timer through Cesium and / or
GPS could be used. Even with a table, the deviation during
On 1/18/14 4:22 PM, Tom Van Baak (lab) wrote:
Add GPS if you want the clock to self-adjust when moved east or west (noon
moves a couple of milliseconds per meter). This feature would be especially
cool if the clock were used in a vehicle.
Ooohh... an automatic self adjusting sundial for
On 1/18/14 2:25 PM, P Nielsen 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.
Once you buy into a microprocessor, it's pretty easy to make all
http://www.precisionsundials.com
The sawyer looks like it fits the bill.
$8,000
Sent from mobile
On Jan 18, 2014, at 4:25 PM, P Nielsen pniel...@tpg.com.au wrote:
I am looking for a physical clock (not software) that will indicate local
solar time. IOW when the sun is at its highest
On 1/18/14 5:11 PM, Bill Dailey wrote:
http://www.precisionsundials.com
The sawyer looks like it fits the bill.
$8,000
Actually, only $2,100.. that fancy helical thing Renaissance was the 8
kilobuck one..
The Sawyer thing has a lot of nice design features. Very clever how
they do the
Lady Heather can display time in LMST/LAST/GMST/GAST
I made a version that has an option to just show the date/time in full screen
mode for Jim Lux/JPL but never heard back from him.
___
time-nuts mailing list
Some time ago I found this - a small algorithm implemented in MSP430 with photoresistor
to synchronise with the sun. Search for Intelligent Dusk/Dawn Light Sensor
Richard S. LaBarbera. Of couse, you asked for a true hardware solution, but maybe this is
interesting for you.
Matthias
On 1/18/14 5:23 PM, Mark Sims wrote:
Lady Heather can display time in LMST/LAST/GMST/GAST
I made a version that has an option to just show the date/time in full screen
mode for Jim Lux/JPL but never heard back from him.
I have passed it on to the person
Thank you for the suggestions so far.
When I said no software, I meant not something like this:
http://www.jgiesen.de/sunmoonclock/index.html
I was hoping someone here might have come up with a cheap quartz clock
driven by a microprocessor, and the necessary code. That would seem to be
the
http://www.pendulumofmayfair.co.uk/view.asp?pid=272cat=Longcase%20Clocks
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow
On Sat, Jan 18, 2014 at 2:25 PM, P Nielsen pniel...@tpg.com.au 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.
Put a stick vertically in the ground.
How about a Fred Flintstone wrist sundial? :-) Isn't that what he wore in
the cartoon?
Actually, the idea of a sundial clock that was mobile sounds pretty cool.
Joe Gray
W5JG
On Sat, Jan 18, 2014 at 5:55 PM, Jim Lux jim...@earthlink.net wrote:
On 1/18/14 4:22 PM, Tom Van Baak (lab) wrote:
I'm working on it now. Got the arduino UNO, need to go get a cheap cook
tomorrow
On Jan 18, 2014, at 18:01, P Nielsen pniel...@tpg.com.au wrote:
Thank you for the suggestions so far.
When I said no software, I meant not something like this:
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 commercial product or kit available for this?
Thank you for any suggestions.
P Nielsen
-Original Message-
From: Jim Lux
Actually, only $2,100.. that fancy helical thing Renaissance was the 8
kilobuck one..
The Sawyer thing has a lot of nice design features. Very clever how
they do the equation of time compensation, and I like the wedge.
I just added a equation-of-time routine to the next release of Lady Heather.
..It can offset the time display by the Equation of Time. The calculated
offset seems to agree rather well (like around 0.01 minutes) with the one on
the NOAA website. It could be made a little better, but that
ll the solutions proposed so far don' meet the criterion that the clock not
be software. It's too esy to make a software display. yu just start with
UTC and apply a formula from an amanac.
But what was requested was something made with gears and springs
I wonder if you really need a special
From: Chris Albertson
ll the solutions proposed so far don' meet the criterion that the clock not
be software. It's too esy to make a software display. yu just start with
UTC and apply a formula from an amanac.
But what was requested was something made with gears and springs
I wonder if
75 matches
Mail list logo
