sun tracker
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Posts: 46,084
Hi Rick and group
Your "two cents" are interesting!
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and a stamp.
The clock with the stamp und the steppers work fine, but I have problems with
the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the pun).
The earth actually turns about 361 degrees per day. It would be easier to
explain with a diagram but here goes. Since the earth rotates on its axis
and revolves around the sun, the earth must turn a little more than 360
degrees per day to play "catch up" to the sun. If you think of the earth
moving in its orbit aorund the sun, it moves around 1 degree per day (360
degrees in 365 days). Since the earth moved through space about 1 degree,
it must turn on its axis an extra degree (361) to point back to the sun.
In other words, if you had a sundial on the earth indicating it is noon, the
earth would turn about 361 degrees to have the sundial say it is noon again.
This is one reason why we have the equation of time. (The difference between
clock time and sundial time). The sun runs "fast" and "slow" at different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the ecliptic
(sun's path on the celestial sphere) so the sun moves a greater distance
eastward per day. At the equinoxes, the sun's path is more of a right angle
to the ecliptic (sun is moving above or below the celestial equator) so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good explainations
regarding this process. The analemma is a figure 8 that show the equation of
time on the X axis and the declination of the sun (or the latitude of sun's
rays 90 degrees overhead) for each day of the year on the Y axis. It used
to be commonly found on old maps and globes in the Pacific Ocean where there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is correct
about the sun moving 1 degree every 4 minutes, but you must remember that is
an average.
If you want to refer to a day as the time it takes the earth to turn exactly
360 degrees, we are talking about a sidereal day (star time). A sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your regular
clock) and go out each night at 9 PM, the star will continually move away
from the branch. If you went out at 9 hours on your sidereal clock each
night, the star will be in the exact same position relative to the tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk another 3 or
4 years.
Rick
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[noparse][[/noparse]Non-text portions of this message have been removed]
Your "two cents" are interesting!
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and a stamp.
The clock with the stamp und the steppers work fine, but I have problems with
the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the pun).
The earth actually turns about 361 degrees per day. It would be easier to
explain with a diagram but here goes. Since the earth rotates on its axis
and revolves around the sun, the earth must turn a little more than 360
degrees per day to play "catch up" to the sun. If you think of the earth
moving in its orbit aorund the sun, it moves around 1 degree per day (360
degrees in 365 days). Since the earth moved through space about 1 degree,
it must turn on its axis an extra degree (361) to point back to the sun.
In other words, if you had a sundial on the earth indicating it is noon, the
earth would turn about 361 degrees to have the sundial say it is noon again.
This is one reason why we have the equation of time. (The difference between
clock time and sundial time). The sun runs "fast" and "slow" at different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the ecliptic
(sun's path on the celestial sphere) so the sun moves a greater distance
eastward per day. At the equinoxes, the sun's path is more of a right angle
to the ecliptic (sun is moving above or below the celestial equator) so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good explainations
regarding this process. The analemma is a figure 8 that show the equation of
time on the X axis and the declination of the sun (or the latitude of sun's
rays 90 degrees overhead) for each day of the year on the Y axis. It used
to be commonly found on old maps and globes in the Pacific Ocean where there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is correct
about the sun moving 1 degree every 4 minutes, but you must remember that is
an average.
If you want to refer to a day as the time it takes the earth to turn exactly
360 degrees, we are talking about a sidereal day (star time). A sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your regular
clock) and go out each night at 9 PM, the star will continually move away
from the branch. If you went out at 9 hours on your sidereal clock each
night, the star will be in the exact same position relative to the tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk another 3 or
4 years.
Rick
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
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Yahoo! Groups Links
[noparse][[/noparse]Non-text portions of this message have been removed]
Comments
tracker any better. Right now i have a device that controls a DC
motor which rotates a PV panel so that it is constantly facing the
sun. It is made of an LM741 op amp used as a comparator and two
photoresistors. When one photoresistor recives more light than the
other it will send either a postive or negative voltage to the DC
motor, which will then adjust the panel until they recieve that same
amount of light. My problem is that my panel is constantly moving.
(it will rock back and forth and never stay completely still). I
was wondering if anyone had any ideas about how to fix this
problem. I would like to incorporate a Basic Stamp II into my
project, but don't know how it would be used yet.
Thanks,
kc8cvf@y... writes:
> I just wanted to know if anyone had any ideas about making my sun
> tracker any better. Right now i have a device that controls a DC
> motor which rotates a PV panel so that it is constantly facing the
> sun. It is made of an LM741 op amp used as a comparator and two
> photoresistors. When one photoresistor recives more light than the
> other it will send either a postive or negative voltage to the DC
> motor, which will then adjust the panel until they recieve that same
> amount of light. My problem is that my panel is constantly moving.
> (it will rock back and forth and never stay completely still). I
> was wondering if anyone had any ideas about how to fix this
> problem. I would like to incorporate a Basic Stamp II into my
> project, but don't know how it would be used yet.
>
I have a Sun Tracker program that follows the sun to keep the voltage on two
solar panels equal. It uses a servo to position the tracker and works very
well. You will have much better luck with a servo that with a DC motor. The
program is written so that the servo remembers where it is and looks for the sun
starting from that point. Please let me know if I can help you.
Sid Weaver
W4EKQ
Port Richey, FL
[noparse][[/noparse]Non-text portions of this message have been removed]
> I just wanted to know if anyone had any ideas about making my sun
> tracker any better. Right now i have a device that controls a DC
> motor which rotates a PV panel so that it is constantly facing the
> sun. It is made of an LM741 op amp used as a comparator and two
> photoresistors. When one photoresistor recives more light than the
> other it will send either a postive or negative voltage to the DC
> motor, which will then adjust the panel until they recieve that
same
> amount of light. My problem is that my panel is constantly
moving.
> (it will rock back and forth and never stay completely still). I
> was wondering if anyone had any ideas about how to fix this
> problem. I would like to incorporate a Basic Stamp II into my
> project, but don't know how it would be used yet.
>
> Thanks,
Are you using a Stamp in the circuit ?
If you are, then you can add a debounce type of delay on the inputs
so it requires some time between actions or it just waits.
If it is just descrete components, then have you thought about
changing the gain on the op-amp ?
As a comparator, it will be at either state depending on the inputs,
and will rarely, if ever, be anything but at one end.
Changing the gain will create a 'window' where the output ramps and
thus creating a bit of a dead-band in the output action.
The larger the window, the greater the deadband and the less reaction
(output) would occur when the two sensors are close to equal.
If your output is linear to the op-amp output, the rotation will slow
as it approaces the desired spot.
A potential problem is that near your dead-band, you might be sending
less DC power to the motor and drain your batteries. In that case you
need another circuit to see if the output is above some value and if
not, then open the line to the motor to eleminate movement.
Dave
'hysteresis' -- aka 'dead band'. You want
to have some comparator values which produce
no output, so your panel will stop at some
point. This means you really need two
comparators -- one for 'too high', and one
for 'too low'.
--- In basicstamps@yahoogroups.com, "Jason Davis" <kc8cvf@y...> wrote:
> I just wanted to know if anyone had any ideas about making my sun
> tracker any better. Right now i have a device that controls a DC
> motor which rotates a PV panel so that it is constantly facing the
> sun. It is made of an LM741 op amp used as a comparator and two
> photoresistors. When one photoresistor recives more light than the
> other it will send either a postive or negative voltage to the DC
> motor, which will then adjust the panel until they recieve that
same
> amount of light. My problem is that my panel is constantly
moving.
> (it will rock back and forth and never stay completely still). I
> was wondering if anyone had any ideas about how to fix this
> problem. I would like to incorporate a Basic Stamp II into my
> project, but don't know how it would be used yet.
>
> Thanks,
Position it so that the tracker moves until a partition blocks the sun
shining on the face of the photoresistor. Then, when the sun moves and
shines on it again, it will move again.
Original Message
From: Newzed@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=e5ogYLKg-fWkcBsGEdomXPNTlV50NkeBuq-Q0dxSRfPOiGJJLzkJU3kM3-_2wv3RDjykB3Us68bt]Newzed@a...[/url
Sent: Monday, March 08, 2004 10:13 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
kc8cvf@y... writes:
> I just wanted to know if anyone had any ideas about making my sun
> tracker any better. Right now i have a device that controls a DC
> motor which rotates a PV panel so that it is constantly facing the
> sun. It is made of an LM741 op amp used as a comparator and two
> photoresistors. When one photoresistor recives more light than the
> other it will send either a postive or negative voltage to the DC
> motor, which will then adjust the panel until they recieve that same
> amount of light. My problem is that my panel is constantly moving.
> (it will rock back and forth and never stay completely still). I
> was wondering if anyone had any ideas about how to fix this
> problem. I would like to incorporate a Basic Stamp II into my
> project, but don't know how it would be used yet.
>
I have a Sun Tracker program that follows the sun to keep the voltage on two
solar panels equal. It uses a servo to position the tracker and works very
well. You will have much better luck with a servo that with a DC motor.
The
program is written so that the servo remembers where it is and looks for the
sun
starting from that point. Please let me know if I can help you.
Sid Weaver
W4EKQ
Port Richey, FL
[noparse][[/noparse]Non-text portions of this message have been removed]
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<grover.richardson@g...> wrote:
> Since the sun just goes from East to West, just use one
photoresistor.
> Position it so that the tracker moves until a partition blocks the
sun
> shining on the face of the photoresistor. Then, when the sun moves
and
> shines on it again, it will move again.
Du'oh !
There is no need to reverse during the DAY !
reverse only needs to be after the end travel or time of day.
Nice catch !
Dave
>
>
Original Message
> From: Newzed@a... [noparse][[/noparse]mailto:Newzed@a...]
> Sent: Monday, March 08, 2004 10:13 AM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
>
>
> In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
> kc8cvf@y... writes:
>
>
> > I just wanted to know if anyone had any ideas about making my sun
> > tracker any better. Right now i have a device that controls a DC
> > motor which rotates a PV panel so that it is constantly facing
the
> > sun. It is made of an LM741 op amp used as a comparator and two
> > photoresistors. When one photoresistor recives more light than
the
> > other it will send either a postive or negative voltage to the DC
> > motor, which will then adjust the panel until they recieve that
same
> > amount of light. My problem is that my panel is constantly
moving.
> > (it will rock back and forth and never stay completely still). I
> > was wondering if anyone had any ideas about how to fix this
> > problem. I would like to incorporate a Basic Stamp II into my
> > project, but don't know how it would be used yet.
> >
>
> I have a Sun Tracker program that follows the sun to keep the
voltage on two
>
> solar panels equal. It uses a servo to position the tracker and
works very
> well. You will have much better luck with a servo that with a DC
motor.
> The
> program is written so that the servo remembers where it is and
looks for the
> sun
> starting from that point. Please let me know if I can help you.
>
> Sid Weaver
> W4EKQ
> Port Richey, FL
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
>
> Yahoo! Groups Links
A simple microswitch at the end of travel can tell you when you are
finished.
Original Message
From: Dave Mucha [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=WAOJEC9630b7CA5v5rCQvbuIlsoe7gJq7hbSMAntJSstFOn1zZ_KxLAEtyc0CD3Cu6trVbULPUfGnxoFYA]davemucha@j...[/url
Sent: Monday, March 08, 2004 4:01 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: sun tracker
--- In basicstamps@yahoogroups.com, "Grover Richardson"
<grover.richardson@g...> wrote:
> Since the sun just goes from East to West, just use one
photoresistor.
> Position it so that the tracker moves until a partition blocks the
sun
> shining on the face of the photoresistor. Then, when the sun moves
and
> shines on it again, it will move again.
Du'oh !
There is no need to reverse during the DAY !
reverse only needs to be after the end travel or time of day.
Nice catch !
Dave
>
>
Original Message
> From: Newzed@a... [noparse][[/noparse]mailto:Newzed@a...]
> Sent: Monday, March 08, 2004 10:13 AM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
>
>
> In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
> kc8cvf@y... writes:
>
>
> > I just wanted to know if anyone had any ideas about making my sun
> > tracker any better. Right now i have a device that controls a DC
> > motor which rotates a PV panel so that it is constantly facing
the
> > sun. It is made of an LM741 op amp used as a comparator and two
> > photoresistors. When one photoresistor recives more light than
the
> > other it will send either a postive or negative voltage to the DC
> > motor, which will then adjust the panel until they recieve that
same
> > amount of light. My problem is that my panel is constantly
moving.
> > (it will rock back and forth and never stay completely still). I
> > was wondering if anyone had any ideas about how to fix this
> > problem. I would like to incorporate a Basic Stamp II into my
> > project, but don't know how it would be used yet.
> >
>
> I have a Sun Tracker program that follows the sun to keep the
voltage on two
>
> solar panels equal. It uses a servo to position the tracker and
works very
> well. You will have much better luck with a servo that with a DC
motor.
> The
> program is written so that the servo remembers where it is and
looks for the
> sun
> starting from that point. Please let me know if I can help you.
>
> Sid Weaver
> W4EKQ
> Port Richey, FL
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
>
> Yahoo! Groups Links
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every 30 sec's. or a preset amount of difference between the photo
resistor voltage levels before changing position.
On Mon, 08 Mar 2004 03:42:04 -0000, you wrote:
>I just wanted to know if anyone had any ideas about making my sun
>tracker any better. Right now i have a device that controls a DC
>motor which rotates a PV panel so that it is constantly facing the
>sun. It is made of an LM741 op amp used as a comparator and two
>photoresistors. When one photoresistor recives more light than the
>other it will send either a postive or negative voltage to the DC
>motor, which will then adjust the panel until they recieve that same
>amount of light. My problem is that my panel is constantly moving.
>(it will rock back and forth and never stay completely still). I
>was wondering if anyone had any ideas about how to fix this
>problem. I would like to incorporate a Basic Stamp II into my
>project, but don't know how it would be used yet.
>
>Thanks,
wrote:
> You could make panel position changes based on time intervals, say
> every 30 sec's. or a preset amount of difference between the photo
> resistor voltage levels before changing position.
I think a lot has to do with gearing of the transmission. Telescopes
are sometimes just set with a stepper motor and run continuously.
We can calculate that there are 360 degress of Sun rotation for 24
hours and that breaks down into about 2.15 degrees per minute.
A simple way would be for the Stamp to look at the two sensors and
determine if the Sun is before or after the proper neutral point and
then make an adjusment.
You are correct that the movement should be somehwhat frequent as
every 30 seconds would attempt to keep the panel within about a
degree of the Sun.
But, also add a continuous movement of some sort so that if clouds
were blocking a good signal, the panel would still follow the general
location of the sun.
Maybe the program could include a POT so as to use the pot for rough
postioning and the sensors as an override when there is enough light
to use for postioning.
Steppers would add more exact postioning for a device without
feedback, but for actual tracking with sensors it looses it's
benifits and acutally uses more circuitry to get the job done.
Interesting project.
Dave
>
> On Mon, 08 Mar 2004 03:42:04 -0000, you wrote:
>
> >I just wanted to know if anyone had any ideas about making my sun
> >tracker any better. Right now i have a device that controls a DC
> >motor which rotates a PV panel so that it is constantly facing the
> >sun. It is made of an LM741 op amp used as a comparator and two
> >photoresistors. When one photoresistor recives more light than
the
> >other it will send either a postive or negative voltage to the DC
> >motor, which will then adjust the panel until they recieve that
same
> >amount of light. My problem is that my panel is constantly
moving.
> >(it will rock back and forth and never stay completely still). I
> >was wondering if anyone had any ideas about how to fix this
> >problem. I would like to incorporate a Basic Stamp II into my
> >project, but don't know how it would be used yet.
> >
> >Thanks,
Dov
Original Message
From: Dave Mucha [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=1-qTiN9zRlLdRnbIra-tBZBgszNXS8KC6IMrEwSHY5_bFMHN0qNRIUs92UGkA0jPupPaTj0agm0jzRmBsw]davemucha@j...[/url
Sent: Tuesday, 9 March 2004 9:04 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: sun tracker
--- In basicstamps@yahoogroups.com, William Tinsley <wetinsley@c...>
wrote:
> You could make panel position changes based on time intervals, say
> every 30 sec's. or a preset amount of difference between the photo
> resistor voltage levels before changing position.
I think a lot has to do with gearing of the transmission. Telescopes
are sometimes just set with a stepper motor and run continuously.
We can calculate that there are 360 degress of Sun rotation for 24
hours and that breaks down into about 2.15 degrees per minute.
A simple way would be for the Stamp to look at the two sensors and
determine if the Sun is before or after the proper neutral point and
then make an adjusment.
You are correct that the movement should be somehwhat frequent as
every 30 seconds would attempt to keep the panel within about a
degree of the Sun.
But, also add a continuous movement of some sort so that if clouds
were blocking a good signal, the panel would still follow the general
location of the sun.
Maybe the program could include a POT so as to use the pot for rough
postioning and the sensors as an override when there is enough light
to use for postioning.
Steppers would add more exact postioning for a device without
feedback, but for actual tracking with sensors it looses it's
benifits and acutally uses more circuitry to get the job done.
Interesting project.
Dave
>
> On Mon, 08 Mar 2004 03:42:04 -0000, you wrote:
>
> >I just wanted to know if anyone had any ideas about making my sun
> >tracker any better. Right now i have a device that controls a DC
> >motor which rotates a PV panel so that it is constantly facing the
> >sun. It is made of an LM741 op amp used as a comparator and two
> >photoresistors. When one photoresistor recives more light than
the
> >other it will send either a postive or negative voltage to the DC
> >motor, which will then adjust the panel until they recieve that
same
> >amount of light. My problem is that my panel is constantly
moving.
> >(it will rock back and forth and never stay completely still). I
> >was wondering if anyone had any ideas about how to fix this
> >problem. I would like to incorporate a Basic Stamp II into my
> >project, but don't know how it would be used yet.
> >
> >Thanks,
To UNSUBSCRIBE, just send mail to:
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from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
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parallel to
the eart rotation axe which is pointed to the polar star, it is called
"equatorial mount"
for telescope which alloud to follow any astral objects observed with a "clock
drive"
that drive only one axe!
Ren
--- In basicstamps@yahoogroups.com, "Grover Richardson"
<grover.richardson@g...> wrote:
> Since the sun just goes from East to West, just use one
photoresistor.
> Position it so that the tracker moves until a partition blocks the
sun
> shining on the face of the photoresistor. Then, when the sun moves
and
> shines on it again, it will move again.
>
>
Original Message
> From: Newzed@a... [noparse][[/noparse]mailto:Newzed@a...]
> Sent: Monday, March 08, 2004 10:13 AM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
>
>
> In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
> kc8cvf@y... writes:
>
>
> > I just wanted to know if anyone had any ideas about making my sun
> > tracker any better. Right now i have a device that controls a DC
> > motor which rotates a PV panel so that it is constantly facing
the
> > sun. It is made of an LM741 op amp used as a comparator and two
> > photoresistors. When one photoresistor recives more light than
the
> > other it will send either a postive or negative voltage to the DC
> > motor, which will then adjust the panel until they recieve that
same
> > amount of light. My problem is that my panel is constantly
moving.
> > (it will rock back and forth and never stay completely still). I
> > was wondering if anyone had any ideas about how to fix this
> > problem. I would like to incorporate a Basic Stamp II into my
> > project, but don't know how it would be used yet.
> >
>
> I have a Sun Tracker program that follows the sun to keep the
voltage on two
>
> solar panels equal. It uses a servo to position the tracker and
works very
> well. You will have much better luck with a servo that with a DC
motor.
> The
> program is written so that the servo remembers where it is and
looks for the
> sun
> starting from that point. Please let me know if I can help you.
>
> Sid Weaver
> W4EKQ
> Port Richey, FL
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
>
> Yahoo! Groups Links
I think that there are 0.25 degrees of rotation per minute of the Earth
24 hoursx60 minutes=1440 minutes per day
1440 minutes per day/360 degrees=4 minutes per degree
Invert that, it becomes:
360 degrees/1440 minutes per day= 0.25 degrees per minute
Scott
I think a lot has to do with gearing of the transmission. Telescopes
are sometimes just set with a stepper motor and run continuously.
We can calculate that there are 360 degress of Sun rotation for 24
hours and that breaks down into about 2.15 degrees per minute.
A simple way would be for the Stamp to look at the two sensors and
determine if the Sun is before or after the proper neutral point and
then make an adjusment.
You are correct that the movement should be somehwhat frequent as
every 30 seconds would attempt to keep the panel within about a
degree of the Sun.
But, also add a continuous movement of some sort so that if clouds
were blocking a good signal, the panel would still follow the general
location of the sun.
Maybe the program could include a POT so as to use the pot for rough
postioning and the sensors as an override when there is enough light
to use for postioning.
Steppers would add more exact postioning for a device without
feedback, but for actual tracking with sensors it looses it's
benifits and acutally uses more circuitry to get the job done.
Interesting project.
Dave
_________________________________________________________________
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Allan Lane wrote:
>
> Brilliant! You only need to move ONE WAY!
>
> --- In basicstamps@yahoogroups.com, "Grover Richardson"
> <grover.richardson@g...> wrote:
> > Since the sun just goes from East to West, just use one
> photoresistor.
> > Position it so that the tracker moves until a partition blocks the
> sun
> > shining on the face of the photoresistor. Then, when the sun moves
> and
> > shines on it again, it will move again.
> >
> >
Original Message
> > From: Newzed@a... [noparse][[/noparse]mailto:Newzed@a...]
> > Sent: Monday, March 08, 2004 10:13 AM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
> >
> >
> > In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
> > kc8cvf@y... writes:
> >
> >
> > > I just wanted to know if anyone had any ideas about making my sun
> > > tracker any better. Right now i have a device that controls a DC
> > > motor which rotates a PV panel so that it is constantly facing
> the
> > > sun. It is made of an LM741 op amp used as a comparator and two
> > > photoresistors. When one photoresistor recives more light than
> the
> > > other it will send either a postive or negative voltage to the DC
> > > motor, which will then adjust the panel until they recieve that
> same
> > > amount of light. My problem is that my panel is constantly
> moving.
> > > (it will rock back and forth and never stay completely still). I
> > > was wondering if anyone had any ideas about how to fix this
> > > problem. I would like to incorporate a Basic Stamp II into my
> > > project, but don't know how it would be used yet.
> > >
> >
> > I have a Sun Tracker program that follows the sun to keep the
> voltage on two
> >
> > solar panels equal. It uses a servo to position the tracker and
> works very
> > well. You will have much better luck with a servo that with a DC
> motor.
> > The
> > program is written so that the servo remembers where it is and
> looks for the
> > sun
> > starting from that point. Please let me know if I can help you.
> >
> > Sid Weaver
> > W4EKQ
> > Port Richey, FL
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> Subject and
> > Body of the message will be ignored.
> >
> > Yahoo! Groups Links
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
<scottdskinner@h...> wrote:
> Hello,
>
> I think that there are 0.25 degrees of rotation per minute of the
Earth
>
> 24 hoursx60 minutes=1440 minutes per day
> 1440 minutes per day/360 degrees=4 minutes per degree
> Invert that, it becomes:
> 360 degrees/1440 minutes per day= 0.25 degrees per minute
>
> Scott
ahh.. what's a couple degrees amung friends : )
I must have missed a key on the calculator.
360 degrees *60 =arc minutes * 60 = arc seconds.
1,296,000 arc seconds per day (24 hours)
360 /24 /60 does equal 0.25 degrees per minute. So, if your stamp
were to look at the posiston once a minute to determine if you need
to move, you would be within +/- one quarter of a degree.
Even a poor loop timer could handle a timing count to check the
inputs once every time period. heck 30 seconds to 2 minutes is an
easy window to create even with a sloppy internal timer.
Dave
>
>
>
> I think a lot has to do with gearing of the transmission.
Telescopes
> are sometimes just set with a stepper motor and run continuously.
>
> We can calculate that there are 360 degress of Sun rotation for 24
> hours and that breaks down into about 2.15 degrees per minute.
>
> A simple way would be for the Stamp to look at the two sensors and
> determine if the Sun is before or after the proper neutral point and
> then make an adjusment.
>
> You are correct that the movement should be somehwhat frequent as
> every 30 seconds would attempt to keep the panel within about a
> degree of the Sun.
>
> But, also add a continuous movement of some sort so that if clouds
> were blocking a good signal, the panel would still follow the
general
> location of the sun.
>
> Maybe the program could include a POT so as to use the pot for rough
> postioning and the sensors as an override when there is enough light
> to use for postioning.
>
> Steppers would add more exact postioning for a device without
> feedback, but for actual tracking with sensors it looses it's
> benifits and acutally uses more circuitry to get the job done.
>
> Interesting project.
>
> Dave
>
> _________________________________________________________________
> Add photos to your messages with MSN Premium. Get 2 months FREE*
> http://join.msn.com/?pgmarket=en-
ca&page=byoa/prem&xAPID=1994&DI=1034&SU=http://hotmail.com/enca&HL=Mar
ket_MSNIS_Taglines
system needs to be added. (To allow for the changing tilt of the earth.)
Dave
Alex Stahl <alex@p...> wrote:
Uh, what happens the next morning :-) ?
Allan Lane wrote:
>
> Brilliant! You only need to move ONE WAY!
>
> --- In basicstamps@yahoogroups.com, "Grover Richardson"
> wrote:
> > Since the sun just goes from East to West, just use one
> photoresistor.
> > Position it so that the tracker moves until a partition blocks the
> sun
> > shining on the face of the photoresistor. Then, when the sun moves
> and
> > shines on it again, it will move again.
> >
> >
Original Message
> > From: Newzed@a... [noparse][[/noparse]mailto:Newzed@a...]
> > Sent: Monday, March 08, 2004 10:13 AM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
> >
> >
> > In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
> > kc8cvf@y... writes:
> >
> >
> > > I just wanted to know if anyone had any ideas about making my sun
> > > tracker any better. Right now i have a device that controls a DC
> > > motor which rotates a PV panel so that it is constantly facing
> the
> > > sun. It is made of an LM741 op amp used as a comparator and two
> > > photoresistors. When one photoresistor recives more light than
> the
> > > other it will send either a postive or negative voltage to the DC
> > > motor, which will then adjust the panel until they recieve that
> same
> > > amount of light. My problem is that my panel is constantly
> moving.
> > > (it will rock back and forth and never stay completely still). I
> > > was wondering if anyone had any ideas about how to fix this
> > > problem. I would like to incorporate a Basic Stamp II into my
> > > project, but don't know how it would be used yet.
> > >
> >
> > I have a Sun Tracker program that follows the sun to keep the
> voltage on two
> >
> > solar panels equal. It uses a servo to position the tracker and
> works very
> > well. You will have much better luck with a servo that with a DC
> motor.
> > The
> > program is written so that the servo remembers where it is and
> looks for the
> > sun
> > starting from that point. Please let me know if I can help you.
> >
> > Sid Weaver
> > W4EKQ
> > Port Richey, FL
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> Subject and
> > Body of the message will be ignored.
> >
> > Yahoo! Groups Links
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
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Do you Yahoo!?
Yahoo! Search - Find what you’re looking for faster.
[noparse][[/noparse]Non-text portions of this message have been removed]
for a long period of time (a comparitor tells the stamp that there is no
sun), the stamp says, ok, it's night, let's get in position for the next
morning's sunup. The stamp moves the positioner to a place where the sun
should be visible (reverse rotation). Likely a position slightly too far.
Then, when the sun comes up, the comparitor flops and tells the stamp that
the sun is up. The stamp would then move the positioner until the partition
blocks the sun again, and we are again running in our normal daylight
mode<G>.
Think of driving into a sunset with the sun visor down. You move the visor
down. Then you move your head up until the sun isn't in your eyes. If your
head is too low, and the sun is in your eyes still, you keep moving the head
up until you can see.
Original Message
From: Alex Stahl [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=9urXaKWOl7h4o5Qjw-UGL7i1EukwvuUOFr7UQIo8kxc3NZBeJJz-sz2ifzgF08EklQapGpZW6A]alex@p...[/url
Sent: Tuesday, March 09, 2004 12:05 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
Uh, what happens the next morning :-) ?
Allan Lane wrote:
>
> Brilliant! You only need to move ONE WAY!
>
> --- In basicstamps@yahoogroups.com, "Grover Richardson"
> <grover.richardson@g...> wrote:
> > Since the sun just goes from East to West, just use one
> photoresistor.
> > Position it so that the tracker moves until a partition blocks the
> sun
> > shining on the face of the photoresistor. Then, when the sun moves
> and
> > shines on it again, it will move again.
> >
> >
Original Message
> > From: Newzed@a... [noparse][[/noparse]mailto:Newzed@a...]
> > Sent: Monday, March 08, 2004 10:13 AM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
> >
> >
> > In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
> > kc8cvf@y... writes:
> >
> >
> > > I just wanted to know if anyone had any ideas about making my sun
> > > tracker any better. Right now i have a device that controls a DC
> > > motor which rotates a PV panel so that it is constantly facing
> the
> > > sun. It is made of an LM741 op amp used as a comparator and two
> > > photoresistors. When one photoresistor recives more light than
> the
> > > other it will send either a postive or negative voltage to the DC
> > > motor, which will then adjust the panel until they recieve that
> same
> > > amount of light. My problem is that my panel is constantly
> moving.
> > > (it will rock back and forth and never stay completely still). I
> > > was wondering if anyone had any ideas about how to fix this
> > > problem. I would like to incorporate a Basic Stamp II into my
> > > project, but don't know how it would be used yet.
> > >
> >
> > I have a Sun Tracker program that follows the sun to keep the
> voltage on two
> >
> > solar panels equal. It uses a servo to position the tracker and
> works very
> > well. You will have much better luck with a servo that with a DC
> motor.
> > The
> > program is written so that the servo remembers where it is and
> looks for the
> > sun
> > starting from that point. Please let me know if I can help you.
> >
> > Sid Weaver
> > W4EKQ
> > Port Richey, FL
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> Subject and
> > Body of the message will be ignored.
> >
> > Yahoo! Groups Links
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
> and Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
To UNSUBSCRIBE, just send mail to:
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embedded PC with date / time and precise sun positions? I say a PC because
the data set is probably too large to encode on a stamp.
On Tue, 9 Mar 2004, Dave Mucha wrote:
> --- In basicstamps@yahoogroups.com, "Scott Skinner"
> <scottdskinner@h...> wrote:
> > Hello,
> >
> > I think that there are 0.25 degrees of rotation per minute of the
> Earth
> >
> > 24 hoursx60 minutes=1440 minutes per day
> > 1440 minutes per day/360 degrees=4 minutes per degree
> > Invert that, it becomes:
> > 360 degrees/1440 minutes per day= 0.25 degrees per minute
> >
> > Scott
>
>
> ahh.. what's a couple degrees amung friends : )
>
> I must have missed a key on the calculator.
> 360 degrees *60 =arc minutes * 60 = arc seconds.
> 1,296,000 arc seconds per day (24 hours)
>
> 360 /24 /60 does equal 0.25 degrees per minute. So, if your stamp
> were to look at the posiston once a minute to determine if you need
> to move, you would be within +/- one quarter of a degree.
>
> Even a poor loop timer could handle a timing count to check the
> inputs once every time period. heck 30 seconds to 2 minutes is an
> easy window to create even with a sloppy internal timer.
>
> Dave
>
>
>
> >
> >
> >
> > I think a lot has to do with gearing of the transmission.
> Telescopes
> > are sometimes just set with a stepper motor and run continuously.
> >
> > We can calculate that there are 360 degress of Sun rotation for 24
> > hours and that breaks down into about 2.15 degrees per minute.
> >
> > A simple way would be for the Stamp to look at the two sensors and
> > determine if the Sun is before or after the proper neutral point and
> > then make an adjusment.
> >
> > You are correct that the movement should be somehwhat frequent as
> > every 30 seconds would attempt to keep the panel within about a
> > degree of the Sun.
> >
> > But, also add a continuous movement of some sort so that if clouds
> > were blocking a good signal, the panel would still follow the
> general
> > location of the sun.
> >
> > Maybe the program could include a POT so as to use the pot for rough
> > postioning and the sensors as an override when there is enough light
> > to use for postioning.
> >
> > Steppers would add more exact postioning for a device without
> > feedback, but for actual tracking with sensors it looses it's
> > benifits and acutally uses more circuitry to get the job done.
> >
> > Interesting project.
> >
> > Dave
> >
> > _________________________________________________________________
> > Add photos to your messages with MSN Premium. Get 2 months FREE*
> > http://join.msn.com/?pgmarket=en-
> ca&page=byoa/prem&xAPID=1994&DI=1034&SU=http://hotmail.com/enca&HL=Mar
> ket_MSNIS_Taglines
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
>
Sean T. Lamont, Chief Mad Scientist |-- lamont@a...
Zen Chemical Productions |-- http://www.zenchemical.com
Fabricators of Unnecessary Amazement
> Uh, what happens the next morning :-) ?
It is posssible to have a set of motions in the Stamp that will move
the panel in rotation to point to the Sun 24 hours a day. Of course
the Earth will be in the way, but when it breakes over the horizion,
the panel would be still tracking it.
As we found out, all you need to do is move the mount so it spins
0.25 degrees per minute.
Dave
>
> Allan Lane wrote:
> >
> > Brilliant! You only need to move ONE WAY!
> >
> > --- In basicstamps@yahoogroups.com, "Grover Richardson"
> > <grover.richardson@g...> wrote:
> > > Since the sun just goes from East to West, just use one
> > photoresistor.
> > > Position it so that the tracker moves until a partition blocks
the
> > sun
> > > shining on the face of the photoresistor. Then, when the sun
moves
> > and
> > > shines on it again, it will move again.
> > >
> > >
Original Message
> > > From: Newzed@a... [noparse][[/noparse]mailto:Newzed@a...]
> > > Sent: Monday, March 08, 2004 10:13 AM
> > > To: basicstamps@yahoogroups.com
> > > Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
> > >
> > >
> > > In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
> > > kc8cvf@y... writes:
> > >
> > >
> > > > I just wanted to know if anyone had any ideas about making my
sun
> > > > tracker any better. Right now i have a device that controls
a DC
> > > > motor which rotates a PV panel so that it is constantly facing
> > the
> > > > sun. It is made of an LM741 op amp used as a comparator and
two
> > > > photoresistors. When one photoresistor recives more light
than
> > the
> > > > other it will send either a postive or negative voltage to
the DC
> > > > motor, which will then adjust the panel until they recieve
that
> > same
> > > > amount of light. My problem is that my panel is constantly
> > moving.
> > > > (it will rock back and forth and never stay completely
still). I
> > > > was wondering if anyone had any ideas about how to fix this
> > > > problem. I would like to incorporate a Basic Stamp II into my
> > > > project, but don't know how it would be used yet.
> > > >
> > >
> > > I have a Sun Tracker program that follows the sun to keep the
> > voltage on two
> > >
> > > solar panels equal. It uses a servo to position the tracker and
> > works very
> > > well. You will have much better luck with a servo that with a
DC
> > motor.
> > > The
> > > program is written so that the servo remembers where it is and
> > looks for the
> > > sun
> > > starting from that point. Please let me know if I can help you.
> > >
> > > Sid Weaver
> > > W4EKQ
> > > Port Richey, FL
> > >
> > >
> > > [noparse][[/noparse]Non-text portions of this message have been removed]
> > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the
> > Subject and
> > > Body of the message will be ignored.
> > >
> > > Yahoo! Groups Links
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
The earth actually turns about 361 degrees per day. It would be easier to
explain with a diagram but here goes. Since the earth rotates on its axis
and revolves around the sun, the earth must turn a little more than 360
degrees per day to play "catch up" to the sun. If you think of the earth
moving in its orbit aorund the sun, it moves around 1 degree per day (360
degrees in 365 days). Since the earth moved through space about 1 degree,
it must turn on its axis an extra degree (361) to point back to the sun.
In other words, if you had a sundial on the earth indicating it is noon, the
earth would turn about 361 degrees to have the sundial say it is noon again.
This is one reason why we have the equation of time. (The difference between
clock time and sundial time). The sun runs "fast" and "slow" at different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the ecliptic
(sun's path on the celestial sphere) so the sun moves a greater distance
eastward per day. At the equinoxes, the sun's path is more of a right angle
to the ecliptic (sun is moving above or below the celestial equator) so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good explainations
regarding this process. The analemma is a figure 8 that show the equation of
time on the X axis and the declination of the sun (or the latitude of sun's
rays 90 degrees overhead) for each day of the year on the Y axis. It used
to be commonly found on old maps and globes in the Pacific Ocean where there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is correct
about the sun moving 1 degree every 4 minutes, but you must remember that is
an average.
If you want to refer to a day as the time it takes the earth to turn exactly
360 degrees, we are talking about a sidereal day (star time). A sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your regular
clock) and go out each night at 9 PM, the star will continually move away
from the branch. If you went out at 9 hours on your sidereal clock each
night, the star will be in the exact same position relative to the tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk another 3 or
4 years.
Rick
is'nt linear, but happens slowly - Adjustment every ten days
might suffice, something a lookup table could do...
Jack
than lowers for over 50 years.
Maybe someone can contact a member of a local astronomy club and get
some information on a mount that is used for automation of telescopes. I
believe it is called sidereal mount. This puts all the motion control in
a single plane, i believe. Much easier to handle than a az-el mount for
tracking any heavenly body.
Spence
k4kep
appropriate angle so that as the sun travels across the sky, it always
points at it.
One way easy to look at it. You won't need math or a compass. Make a quick
sun dial. Just a sharp nail over a piece of wood (I would suggest something
about a foot long for ease, so a sharp piece of wood makes better sense<G>).
Early in the morning, after sunup, make a mark on the wood where the tip of
the shadow is laying on the wood. In the evening, before sundown, make
another mark. Now you have 3 points on the plane of a sideral mount.
Measure the angle (cut a piece of cardboard even<G>), and make your mount
angled in the same direction.
However, the appropriate angle will change slowly over the days.
I suspect greatly that there are satellite programs that could be adapted
(or already are adapted) to this from the amateur radio rhelm<G>. But not
being a satellite user, don't know for sure.
Original Message
From: BOYD S. MINER [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=1YmlRUjIct0JFaC24jiNZVneT7QpgeiZRBXu5ZOc5lmTG5o3GPPfW2EauVLhqPD6f1taNskeTkngszKF5Fo]k4kep@b...[/url
Sent: Wednesday, March 10, 2004 1:42 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: RE: SUN TRACKER
I'M NOT SHOUTING. I HAVE BEEN ABLE TO READ AND TYPE ALL CAPS MUCH EASIER
THAN LOWERS FOR OVER 50 YEARS.
MAYBE SOMEONE CAN CONTACT A MEMBER OF A LOCAL ASTRONOMY CLUB AND GET SOME
INFORMATION ON A MOUNT THAT IS USED FOR AUTOMATION OF TELESCOPES. I BELIEVE
IT IS CALLED SIDEREAL MOUNT. THIS PUTS ALL THE MOTION CONTROL IN A SINGLE
PLANE, I BELIEVE. MUCH EASIER TO HANDLE THAN A AZ-EL MOUNT FOR TRACKING ANY
HEAVENLY BODY.
SPENCE
K4KEP
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seasons<G>. For a night of observation the change may be ignored<G>.
Original Message
From: Rene Genest [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=KscJBMvuQSR4iaYuZw0kCaQe8BkJfYYJbT0kunPAyYKJq7lp__kXzIx4SwtXxUqytERGQjnvl35K7YieLomR]rene.genest@q...[/url
Sent: Tuesday, March 09, 2004 6:33 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
You do not need "north-south" system, if your "east-west" rotation axe is
parallel to the eart rotation axe which is pointed to the polar star, it is
called "equatorial mount" for telescope which alloud to follow any astral
objects observed with a "clock drive" that drive only one axe!
Ren
Though this statement is fully accurate.
Original Message
From: Dave Mucha [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=jX54_GJ-7zpswQsWC-Mz5_45Y0PpYLcviborML0ks5d9VcIifCjgz0rHftMoLVFv2v8ePo5l5S5MBGs]davemucha@j...[/url
Sent: Tuesday, March 09, 2004 7:36 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: sun tracker
--- In basicstamps@yahoogroups.com, Alex Stahl <alex@p...> wrote:
> Uh, what happens the next morning :-) ?
It is posssible to have a set of motions in the Stamp that will move
the panel in rotation to point to the Sun 24 hours a day. Of course
the Earth will be in the way, but when it breakes over the horizion,
the panel would be still tracking it.
As we found out, all you need to do is move the mount so it spins
0.25 degrees per minute.
Dave
>
> Allan Lane wrote:
> >
> > Brilliant! You only need to move ONE WAY!
> >
> > --- In basicstamps@yahoogroups.com, "Grover Richardson"
> > <grover.richardson@g...> wrote:
> > > Since the sun just goes from East to West, just use one
> > photoresistor.
> > > Position it so that the tracker moves until a partition blocks
the
> > sun
> > > shining on the face of the photoresistor. Then, when the sun
moves
> > and
> > > shines on it again, it will move again.
> > >
> > >
Original Message
> > > From: Newzed@a... [noparse][[/noparse]mailto:Newzed@a...]
> > > Sent: Monday, March 08, 2004 10:13 AM
> > > To: basicstamps@yahoogroups.com
> > > Subject: Re: [noparse][[/noparse]basicstamps] sun tracker
> > >
> > >
> > > In a message dated 3/8/2004 10:07:00 AM Eastern Standard Time,
> > > kc8cvf@y... writes:
> > >
> > >
> > > > I just wanted to know if anyone had any ideas about making my
sun
> > > > tracker any better. Right now i have a device that controls
a DC
> > > > motor which rotates a PV panel so that it is constantly facing
> > the
> > > > sun. It is made of an LM741 op amp used as a comparator and
two
> > > > photoresistors. When one photoresistor recives more light
than
> > the
> > > > other it will send either a postive or negative voltage to
the DC
> > > > motor, which will then adjust the panel until they recieve
that
> > same
> > > > amount of light. My problem is that my panel is constantly
> > moving.
> > > > (it will rock back and forth and never stay completely
still). I
> > > > was wondering if anyone had any ideas about how to fix this
> > > > problem. I would like to incorporate a Basic Stamp II into my
> > > > project, but don't know how it would be used yet.
> > > >
> > >
> > > I have a Sun Tracker program that follows the sun to keep the
> > voltage on two
> > >
> > > solar panels equal. It uses a servo to position the tracker and
> > works very
> > > well. You will have much better luck with a servo that with a
DC
> > motor.
> > > The
> > > program is written so that the servo remembers where it is and
> > looks for the
> > > sun
> > > starting from that point. Please let me know if I can help you.
> > >
> > > Sid Weaver
> > > W4EKQ
> > > Port Richey, FL
> > >
> > >
> > > [noparse][[/noparse]Non-text portions of this message have been removed]
> > >
> > >
> > >
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> > >
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> >
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> >
> >
> >
> >
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fall into the ocean, and still try to play (a try on humor<G>).
The simple method would be to use a two axis mount, and two sensor clusters,
to track sun, no matter what the vehicle movement.
The hard solution (at least in my mind) would be to try to figure out where
the sun is, add in the vehicle position and attitude (is it level for
example), and calculate where to look.
In the simple solution, I would think that some sort of raster scan on start
of the program, to locate the sun, would be in order. Relatively easy to
implement. Then, when the sensors are illuminated by the sun, fine tuning
of the position and tracking begins.
As the vehicle goes under trees, behind buildings, etc., it can get tricky.
I would leave it sitting in the same position for a certain amount of time
(hopefully the building would soon stop blocking the sun, and everything
would continue as normal. Then if the sun doesn't reappear, the vehicle has
changed attitude/angle drastically, and it's time to begin a search again.
The class way, of course, would be to always know the attitude and position
of the vehicle, and the position of the sun. That's more time and money<G>.
Original Message
From: goflo@p... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=SYH2SFxlKQZrcaMdi-JAH_w6WsVReCMttL3-h0GL6ET24NMAqJewTwyuSueA03PDbXrBJXLJmmKuCg]goflo@p...[/url
Sent: Wednesday, March 10, 2004 12:23 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: RE: SUN TRACKER
Grover Richardson wrote:
>
> Yes. A sidereal mount is a single axis mount that is slanted to
the
> appropriate angle so that as the sun travels across the sky, it
always
> points at it...
The appropriate angle is the latitude, so if your panel
is on a vehicle and your stamp can talk to a GPS...
Use # 1024 [noparse]:)[/noparse]
Rube
>
> Yes. A sidereal mount is a single axis mount that is slanted to
the
> appropriate angle so that as the sun travels across the sky, it
always
> points at it...
The appropriate angle is the latitude, so if your panel
is on a vehicle and your stamp can talk to a GPS...
Use # 1024 [noparse]:)[/noparse]
Rube
nice<G>. It's good to see things that work<G>.
All the best..
Original Message
From: goflo@p... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=7bgGJfY-MP2-6mAxq_FTaK31MLNMQaN7PgBBcIifqMM5ZehLFfW3_Bm9atS7AaoTPvA4uea98xkw7cIP]goflo@p...[/url
Sent: Wednesday, March 10, 2004 5:47 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: RE: SUN TRACKER
Grover Richardson wrote:
> If on a vehicle, all mathmatics hell breaks loose...
Perish the thought. I like your elegant shade-seeker
on a sidereal mount - The GPS plus attitude sensor
tells you the angle (latitude +/- attitude), and when
to wake up & secure (longitude and UT), shade-seeker
does the tracking. Should work fine anywhere between
60N & 60S.
regards, Jack
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> If on a vehicle, all mathmatics hell breaks loose...
Perish the thought. I like your elegant shade-seeker
on a sidereal mount - The GPS plus attitude sensor
tells you the angle (latitude +/- attitude), and when
to wake up & secure (longitude and UT), shade-seeker
does the tracking. Should work fine anywhere between
60N & 60S.
regards, Jack
> I would like to calculate the position of the sun, only
> depending, on my position an the earth, and depending, on the date and time.
Heinz -
A marine navigation text would be one source for such
algorithms, such as "The American Practical Navigator",
Nathaniel Bowditch. The Deutsch equivalent escapes me,
but I know it exists. Older editions are better, current
editions spend lots of time on the high-tech stuff, at
the expense of fundamentals & computational solutions
(there are many).
regards, Jack