Solar Tracking With Arduino [Intelligent System]


Introduction: Solar Tracking With Arduino [Intelligent System]

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The solar tracking works on the principal of astronomical equations. With the help of the equation it calculates the coordinates of the sun by calculating the elevation and azimuth angle given the latitude, longitude and time zone of a given place. The use of a tracking system greatly improves the power gain from solar radiation. The amount of current a PV panel produces has a direct correlation with the intensity of light the panel is absorbing.

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Step 1: Items Required

1. Servo Motors (2nos) : Geared servo motor most suitable for this project. (Available here:

2. Xbee (2nos): This is required for wireless communication between the Arduino Board and the PC. (Available here:

3. Xbee Arduino Sheild: For interfacing Xbee with Arduino Board (Available here:

4. Arduino Board (Available here:

5. Pan Tilt Structure : This will help to hold the solar panel and for the servos to be kept in the right position (Available here:

6. Solar Panel : A small solar panel of rating 1W is sufficient for this project (Available here :

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Step 2: How It Works?

The software uses complex mathematical astronomical equations to determine the position of the sun very accurately. The inputs required by the software include the Latitudes, Longitudes and time zone of the location by the user. Other inputs like date, hour, minutes and seconds are taken by the LabVIEW program from the computer system. The software system calculates the azimuth and elevation angle which is fed to the Arduino board wirelessly via XBee chip. Based on the information the Arduino board generates a PWM signal proportional to the angle it gets from the software. The PWM signals are fed to the servo motors to rotate the pan tilt structure on which panel is mounted.

Solar tracking project is divided into two modules: software module and hardware module. Both software and hardware modules have to work in synchronism in order to achieve solar tracking.

One of the unique feature of the project lies in the ‘Sun Trajectory Tab’.This tab provides the information of the sun trajectory with the help of both 2D and 3D graphs along with the current position of the sun. A 2D graph is plotted ‘Elevation Angle’ vs ‘Azimuth Angle’. Whereas the 3D graph gives a more comprehensive outlook to the trajectory of the sun with the directions marked. The trajectory of the sun for both 2D and 3D graph is plotted by simulating the algorithm from sunrise to sunset thus plotting points for each second of the day.

The hardware module comprises of the following components: mechanical components, HS-311 servo motors, Arduino Board, XBee shield, XBee and 1W solar panel. It also is responsible to hold the solar panel and aligned it to the sun. Which helps it to attain the maximum efficiency from the solar panel while wirelessly communicating with the software module.

Step 3: Detailed Video

For more information watch the video.



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    Uhm, nice, but ... why just not use photoresistors? It would not be that precise (and sciencey), but do I need a 100 % precision in (let's say) auto-adjusting a solar panel rack?

    5 replies

    Thank you for your kind words of appreciation.

    That's a very good question you asked. Please let me explain you, yes using photoresistors will make it simple and and you don't have to worry to much about complex algorithms and equations.But photoresistors approach is only good as a science experiment and will not hold good in outdoor conditions.

    Let's say you have on and off cloud cover in your area which means you will have cloud shadows falling on the solar panel which will make it move to the brightest spot in the sky and once the cloud is gone it will again move towards the direction of the sun, thus going all cranky in the process which implies that unnecessary power will be wasted most of the time adjusting the solar panel.

    Whereas in this approach (the one mentioned in the instructable) the smart algorithm will always calculate the exact position of the sun and keep the solar panel aligned no matter what thus being more efficient.

    I hope I was able to give a satisfactory answer to your question.

    Okay, I see your point there. ;o)

    The approach I was mentioning I once saw in some sort of urban post acpocalyptic survival show, where they basically velded a tube frame with (large) solar panels and used arduino / Raspi with some photoresistors and a motor to adjust the panels position during the day. I believe tho, they had a cover around the photoresistors too, to basically make the shadow deeper, when the panel went off the ideal angle. I liked that makeshift idea pretty much.

    I mean, your approach is very solid - and more advanced and complicated so it depends on what level of precision one needs. will check your ible on my desktop once again. o)

    Sure thing !

    And if you have any suggestions for the solar tracker do let me know.

    Have a nice day !

    Wow !
    That was something really interesting !
    Thanks for sharing.