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Solar tracker - compare voltages

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solar tracker

Hello,

I am trying to design a solar tracker. Where it is used photodiodes. There are 2 diodes. And in sun they give a voltage of 2.1 volt. I will set it such if voltage from D1 is higher than D2 so it will be compared in some IC and sent out a signal so Motor1 will adjust it such as until the device is on correct position. Where a third diode D3 detects it is on correct position and then shut down the motor. And same if D1 is higher then D2 so it will turn on Motor2 and adjust until it comes on correct position and D3 detects and shutdown.

Where i only need a IC which can accept 2 input voltage and 2 output voltage. And compares which one is higher and send signal only to output1 or output2.

Thanks
 

compare voltages

I think your tracker needs more than just photodiode sensors. Your principle is correct but not practical.

You will need some sort of 'intelligence' from a microcontroller as well as sensors to make good decisions on the motor activation times. You also have to bear in mind that your motor should be using as little power as possible so you do not waste the gains from using a tracker and that overnight you need to return your panels back to face the rising sun. If you don't return them, the chances are that by morning your photodiodes will be in shadow of the panel and never work again!

I think what you really need is two photocells, facing the same direction as the panel but with a small raised divider between them so that unless facing in exactly the right direction, one or the other will have the shadow of the divider cast upon it. You can use a microcontroller to directly measure the voltage from the cells. You need to drive your motor so the voltage from the cells is equal. I don't think a third sensor is necessary. You only need to check the two voltages perhaps once every few minutes, if you do it more often you may find the panel 'hunts' side to side as it tries to correct for noise, clouds etc.

If all you are doing is trying to optimize the output from a PV panel, a much easier way is simply to rotate it at a fixed speed on a polar (angled pivot) mount and then reverse it back again after dark. That method eliminates all sensors and just uses timers. It may not be quite as efficient but the loss would be very small and the cost much less.

Brian.
 

need of solar tracker

You may use a quad op-amp like LM124 or LM324 to compare two signals and use other two op-amps as required to drive the motor or any other task. Good luck
 

Solar tckr - How to point the system to the East by itself?

I want to build a Solar Tracker Positioning System! I want it, in a way that it can point to the East by itself. I do not know how to do it. Implementing a GPS will not work since you are requiered to move first for GPS to work. I do not know if it will wor with an electronic compass. Then finally I do not know much about programming micrcontrollers. Any idea??
 

Hi mini, welcome.
I have a program that tracks sun (and moon) position from your location. It is Geoclock, (not for linux) and should be somewhere on the web. Displays the angles at the bottom right of its screen.

There is other simpler programs that do that too, like :

http://www.stargazing.net/kepler/sun.html

They need no sensors, work cloudy or not. The purpose of tracking may be to aiming solar panels, or for heliostats. They are different animals and their mechanisms are not the same.

Miguel
 

Where I live, east is always in the same direction. Come to think of it, so is north, west and south.

As far back as I can remember, the sun came up in the same direction too.

Brian.
 

Presumably you want track the sun in the east-west direction and realigns itself every night to east to catch the next day? Use a compass to align the east-east direction, and thats it. The rest is electro-mechanical.
 

We need 2 have atleast two sensors (east and west) which is able 2 provide analog output when light of appropriate intensity falls on it.So I would recommend better use 2 ADC which provides digital output.The putput should be fed to the port of microcontroller and should be compared using appropriate algorithm.Use H bridge configuration for d motor whose torque would be decided thru the weight of the panel.The gate driver for mosfet used for H bridge configuration could be decided using two pins of any port of uC.
 
I found yet an interesting & new Ref. Design from On Semi for Solar Power MPPT...
K.
 

need someone to design for me...solar tracking system using microcontroller and 8 ldr sensor please
 

Ravi Verma said:
We need 2 have atleast two sensors (east and west) which is able 2 provide analog output when light of appropriate intensity falls on it.So I would recommend better use 2 ADC which provides digital output.The putput should be fed to the port of microcontroller and should be compared using appropriate algorithm.Use H bridge configuration for d motor whose torque would be decided thru the weight of the panel.The gate driver for mosfet used for H bridge configuration could be decided using two pins of any port of uC.
Click to expand...

Hi Ravi,

Would using a mircoC that can take in analog signal directly wont help? Do we still need a ADC?

See with an H bridge configuration, would one be able to run the dc motor bi-directionally? Is it possible to run motor bi-directionally with use of relays and microC itself? or only options left are servo/stepper to be used and not the traditional dc motor?

can you please advise ?

regards
nghtyvbz
 

Hey,

You can use two LDRs if you want to make a solar tracker. By the way, for single axis only. Then use PIC16f877a to compare voltages from each direction. Use the ADC module for that. Also, you can use a servo motor for that. It's so simple to program servos. Or maybe you can use a stepper motor. But I prefer more servo motors.

Note:
You must have a tolerance between the two voltages. This is very important.

Cheerz!
Felipe
 

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