Hi, I am trying to build a Solar tracker.
I originally used the plans from http://pages.prodigy.net/rich_demartile/ but although it worked well in bright sunlight, it isn't sensitive enough.

I then came up with the attached circuit.
In the circuit where I have got Pots, I intend to put green LED's

I think that it will work.

What do you think?

Attached Files

L293d - Tracker. - wip.pdf (6.3 KB, 334 views)

__________________
Rick...

Science and sound engineering will always prevail in the end
"for nature cannot be fooled" [Feynman]

 

Hi meyrickt,

I guess that tracker won't work well. I didn't spy sensors yet.

Here is a circuit with enough sensitivity even on hazy days. It uses 10mm red LEDs with a clear dome as sensors. With no direct sunlight the output voltage is about 25mV, good enough for an amplifier for a useful signal.

The circuit I suggest takes care of both, azimuth and elevation angle for the panel to track the sun.

Attached is a complete schematic and also a layout. The files were created using Eagle version 4.16, but can be importet to the latest version (5.0) without problems. The board size exceeds the restriction of the free version, but due to programmmer's error a ready made circuit can be loaded as is.

If there are any questions about how to adjust the circuit don't hesitate to PM me. The relays used fit into a modified DIL16 socket and that way they can easily be replaced in case the contacts burn off. Max. load is 2A at 24V.

Regards

Hans

P.S. I have also designed an automatic "homing circuit" which moves the panel towards the "sunrise position" after sunset. The time when to start moving depends on the twilight duration and that circuit takes care of that by programming the homing timer accordingly.

Attached Files

SUN-TRACKER.zip (38.4 KB, 331 views)

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Proper Planning Prevents Piss Poor Performance

 

Hi,
In the circuit I gave, I will replace the potentiometers with green LEDs.

Basically, as I have never used OP Amps before (I have been out of electronics a looooooog time) I would like to know if my configuration will work.

I have used the Livewire circuit simulation software to test it, and it seems to work. However I do not have a great deal of faith in it as there seem to be a few bugs in it.

Boncuk: I will download Eagle and have a look. Thanks

__________________
Rick...

Science and sound engineering will always prevail in the end
"for nature cannot be fooled" [Feynman]

 

Ive redone the circuit to make it more readable, and to show the position of the LEDs

Attached Files

L293d - Tracker. - wip.pdf (5.7 KB, 209 views)

__________________
Rick...

Science and sound engineering will always prevail in the end
"for nature cannot be fooled" [Feynman]

 

Hi meyrickt,

the circuit will work as a window comparator and switch the drive forth and back continously.

The circuit I suggested works with opposite polarized voltages from the sensors, meaning the voltage output of the sensors is zero if they have equal sunlight.

Depending on the relative direction of the sun there will either be positive or negative output voltage increasing with different light intensity.

Hans

__________________
Proper Planning Prevents Piss Poor Performance

 

Hi,
I am trying to design a circuit for a solar radiation detector. Only I know is that the tracker should be microprocessor controlled, to be able to calculate solar position and drive the motor in order to position the detector directly to the sun's rays. Also the mechanism should be able to function under clock or sun mode.

Which basic components I must use?
I hope my question is clear enough and you will be able to help me with circuit diagram and much more.

 

Hi Marcelino,

basically you could use the same as for the sun-tracker. To have the tracker move with no sunlight the drive must have a reduction gear which allows movement of exactly 0.25degrees of azimuth change per minute. (360/24/60).

To determine the sun's position relative to your location you require the elevation and azimuth angle of the tracker. The momentary zenith of the sun (position above the earth where it would fall) using elevation angle is difficult to calculate, since the sun's appearant movement depends a lot of the latitude of your location. Even at the equator the elevation angle swings +/- 23.5 degrees during a year.

You need to employ the appropriate formulas in your program. You might google "astronomic navigation" for the formulas. Using these formulas you can program the tracker to follow the predetermined elevation angle without sunlight, too. The result will never be the same, not even at the same day in two years and change daily - moreover hourly.

Another solution would be to integrate the entire Air Almanach in your program. Saves a lot of calculation (calculations are already done). Disadvantage of that method: required RAM space approximately 4GB. Advantage: Precession and nutation (the earth doesn't rotate about a fixed axle, but also tumbles a little bit) of the earth are also readily calculated.

Hans

__________________
Proper Planning Prevents Piss Poor Performance

 

Great sun tracker. Includes all parts and its already built. I am new here so going to assume i can't put links here. So if you goo gle red rock and solar tracker, you should come up with the site. At 35 or 50 bucks, you can't go wrong.
No worries,
Julesfl

 

The circuit with the green LEDs as sun sensors won't work.
The inputs of an LM324 opamp are PNP transistors so their input bias current will cause the inputs connected to the LEDs to float high.

If the polarity of the LEDs are reversed and the input of each opamp has a resistor to ground to drain the input bias current then the circuit will sort-of work but without hysteresis it will chatter when the inputs are almost the same.

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Uncle $crooge

 

I have researched this sun tracker. Have You? I never ass sume anything.
If you google this product, many people use it., so is this not what the person needs?
No worries,
Jules