Dual Axis Solar Tracker

by OpenSourceClassroom, published

Dual Axis Solar Tracker by OpenSourceClassroom Feb 23, 2013
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If you have made this thing, PLEASE take pictures and post! Thanks.

This is a simplified dual axis tracker for small solar projects. Notice that the weight of the tracker is NOT putting pressure on the servo motors. The pitch gear is nestled inside the bracket which reduces wobbliness and makes the installation look professional. For the horizontal gear system it just made sense to attach the entire panel mount directly on the gear. It makes for a really solid structure. This was my first attempt at a project like this. Let me know how it works out if you build one... Enjoy!
Here are video links:
Here is a simiar project with no printed parts:


You need: Arduino Uno, (2) SG90 Micro servo motors, (4) LDRs, breadboard, wires, rainbow ribbon cable for LDRs, 4" long 1/4" bolt and nut.
Print all parts.
Attach horizontal servo motor to tracker base before attaching the horizontal gear or you will have trouble with tool access to get the motor mounted. The vertical servo gear should be ok to assemble first due to the smaller size. To mount the gears to the servo motors, I cut tiny brass nails just a bit smaller than the thickness of the gears and made little groves on the nail to give a rough surface for the plastic to bond to. I then used a soldering iron to heat the nail and fuse it through the white servo gear attachment and then into the plastic gear. Makes for a nice, clean installation. Just make sure that your gear is exactly centered when you mount it to the servo.
Attach motors, gears, and panel mount.
Hook up wires according to schematic.
Load program into Arduino and test it out.
Depending on the light that you use to move your tracker around, you might need to change the resistor size on breadboard (they should all be equal value, higher value resistors for less light).

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hello thank for this awesome project. Can you tell me the wight of this project without circuit. thank

your design is great!

I would like to know if you can pass the pieces in the file to modify it in the solid works, there is no .stl file, it is for a project and I think it's a simulation and you can not do that because the pieces are displayed as a mesh and you can not help

Thanks, if I can do it Upload the photos or a video.

buenas, esta genial tu diseño !

quisiera saber si puedes pasarme las piezas en archivo para modificar en solid works, no archivo .stl, pues es para un proyecto y me exigen simulación y no he podido hacerla debido a que las piezas las visualiza como una malla y no solida.

Gracias, si logro hacerlo subire las fotos o un video.

hi everyone did anybody try changing the board arduino uno with "nano v3"??
did anybody try arduino nano v3??

Comments deleted.

Hi. nice job!
Have you already measured how much power is needed for the servo and whats the increasement of the solar panel power?

Hi. nice job. will you please tell me the features of the solar panel used in this? is it different to yse other kinds of solar panels for this project?

Hey, what is the weight of the used plastic? Thanks for the great model! ;)

This is nice, only thing is I need to know the resistor value you used in the tracker you have in your video. I printed all the parts.
Made an acces hole in the horizontal gear to attach it to the servo. I'm ready to wire but I need those values to get started.
I'll show it when is finish and working.
Very nice and simple design.


great project :) busy printing it now, altho i firsat checked your code worked and wired the lot up lol, thanx for the interisting and usefull project

great thing! You are amazing!

But... Where the arduino code and schematic? :X

Look at the thing files listed. The arduino file is there (.ino) and the schematic is a pdf file.

How did you connect the solar panel to the ardurino? Is there a schematic?

Sir. Yesterday i tried to order the printed material i did all of the steps but at the end the say Unseccusful filed .

I am wondering do you actully sell t it or not ?

Brother , can I pay this set up the gears vertical and horizontal from this website ?

brother , does the Schematic diagram same as the coding , so just direct apply the coding into the arduino uno right ?
because if you see the diagram the top ldf LDR connect at pin A1 and for your coding it connect to A0 so i got confuse can check and tell me please ?

I mean the gears and the other stuff .

Also if i want to use dc motor instead of servo still same coding or need some modification

Do you not have your own 3D printer...? If you use different motors, you will definitely need to change the coding. DC motors and servos are completely different in how you control them. Try asking google... I bet there is a similar project out there using DC motors instead of servos.

Comments deleted.
Comments deleted.

Nice job , where i can find the code of this project ? , becuse i am about to do it , also do you recommand me to buy the printed material.

I need the code of this project i am about to buy the printed material

The arduino code is provided in the list of files and I'm not sure what you mean about recommending you buy the printed materials...?

Nice design and good work!

What size is your panel?

Can this be run on a Arduino Nano V3.0 (that costs like $2-3)...since they are MUCH smaller and can pretty much do everything the UNO can?

And if it can...can the base be designed smaller and then with a full (weatherproof) enclosure?

I looked up the specs for the SG90 servo 22 x 11.5 x 27 mm vs the Traxxas 2056 High-Torque Waterproof Servo 40.5 x 20.5 x 36mm, maybe a little upscaling or tweaking of the servo slots and an enclosure that can be sealed and this thing could run larger panels

Very cool design!

Yea man... Hack it up!!! When I designed this thing over 3 years ago, the Arduino Nano didn't even exist.


Can i use 10 Watt Solar Panel with this design ?

You can use what ever size that you want as long as the motors will support the weight... The one in the picture is a 6V 3.4W so I'm not how much bigger those little SG90 servos can support. You may have to redesign and use some bigger servo motors but the arduino code and wiring can remain the same. Good luck!

also, how did you attach your solar panel to the board?

also also, does this thing hold a solar panel big enough to produce enough power to be worth it? I mean...does the power generated exceed the additional power required by having to power 2 servos and arduino? Im wondering if solar panel sitting on the ground to battery to divice would be more effecient....

also also also, now that I have printed all the pieces and started putting this together, I see the design of the pieces is pretty bad.

  1. No mounting holes for horizontal gear. not even a center mark, which would take 2 seconds to add
  2. Its impossible to use a screw to attach the servo arm to the horizontal servo because there is no access, you just have to push it on and hope it stays after you mount the gear to the arm.
  3. The base plate is way over sized which leads to wasted material and huge print times.
  4. the base gear shaft is too long which makes the entire tracker assembly wobble back and forth on the base plate.
  5. You could easily design round-to-square pegs to fit into square holes (instead of round holes) on the base gear and panel, eliminating the need for additional hardware, and reducing weight.

Someone should really remix this and upload it.


You know... With as much time as you spent writing all of these negative things about this project, you probably could have remixed it yourself!

it takes like 5 minutes to leave a comment...if that...

This looks like a really fun project thanks for sharing it with us! Im printing the parts now. I was just wondering, do you know what value resistors to use to track the sun? Thanks.

hello can i ask u..wht are u used for combining panel mount and panel braket..i saw u use iron rod with screw..wht size is needed to combine tht two ...

It says what size bolt you need in the instructions section.

give me flowchart this program ^^
[email protected]

Can Stepper Motor be used instead of Servo?

i my name is victor,and i´m doig this project,
but not work correctly.
Someone tested this code?
help me, my email is [email protected]

i my name is victor,and i´m doig this project,
but not work correctly.
Someone tested this code?
help me, my email is [email protected]

Hi there. I was thinking you could use a motion sensor as well. Then you could put a camera on the platform. Has anyone tried this?

Hi, its a lovely design

i would like to mod it and use it as an antenna tracker... what tool did you make this in?

Try using Autodesk Meshmixer. It's free and you can load in STL files and make alterations to them. Its a pretty cool program.

I guess it would also possible to scale this up for bigger servo correct? Planning to use this for antenna tracker

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I guess it would also possible to scale this up for bigger servo correct? Planning to use this for antenna tracker

Can someone please explain the Arduino code below? I am confused by "analogRead(4)/20" and "analogRead(5)/4" because based on schematic, it does not look like analog pins 4 and 5 are used.
int dtime = analogRead(4)/20; // read potentiometers
int tol = analogRead(5)/4;

Sure thing. This arduino code was originally sourced from http://www.instructables.com/id/Arduino-Solar-Tracker/http://www.instructables.com/i... but after configuring the code with the printed parts, I did not use the potentiometers in the circuit. We just changed the resistors depending on the intensity of the light source being used. In the classroom with an artificial light source, the extra use of potentiometers seemed to complicate the project and therefor were not used. I assume that the section of code you are referring to can be removed without disturbing the functionality of the system.

I really like this sun tracker. Just a question, what is the maxium size solar panel this setup can handle? I'm looking for a solution that can handle a 10kg ~100W panel with the dimensions 100x70x4 cm

Not sure if this mechanical design can support a 10kg panel. You will probably need to design a larger capacity mechanism and use larger servos with an increased power supply.

You did a great Job on this project and have provided me a great idea that I wanted to share. Why not inverse the horizontal gear from the outside of the base to the inside? Place the stepper motor under the column created. This would minimize your base foot print and may even allow you to mount the whole slew gear onto a poll. I like it because it expanded my mind to what is possible. You helped me greatly by providing the "spark". Thanks!

Hi there, I was wondering if you could post the Inventor file for the vertical servo gear. I am going to add a small hole in the center of the gear so I know exactly where the center is when adding it to the servo

How much power does one get with this setup? Anyone do performance benchmarks yet? Ideally one could setup 2-3 of these in a backyard or something and print recycled plastic from solar power.

where did u buy the parts for this??

Online. Just search for the light dependent resistors, Arduino, and SG90 Micro Servo. I think I got the solar panel through Adafruit's website

Hi Rob,
Nice work.
Where do i connect the potentiometer?
where are the 3 pins connected ?


There is no potentiometer. In the download files you will find a wiring diagram that I put together using powerpoint. That should help you tremendously.

Thanks for sharing this project. You did such good job on it I had to build one, so... I'm printing the parts now, and should have it assembled and working by tomorrow. With my Dimension printer total print time will be about 22 hours which is not too bad. I'll post a picture when it's done.

How do you like the Dimension printer?

It's a great printer. The print quality is excellent and the support system is very clever, but like all of them it's slow. The only down side is the cost of the feed stock.

Mainly ABS plastic right? Is your dimension printer... yours or for a school? Aren't they super expensive?

Sweet! Just be careful with the Arduino code. Make sure that your sensors are easily distinguishable when plugging into arduino. Your code should reflect that exactly. That was the biggest hurdle I had with the project. That's why I found the multicolored ribbon cable to be helpful. I drew the schematic on ppt based on my model. Your model may be a little different depending on what color wires you use.

The parts are finished, assembly tonight!

post a video of it... I am going to make one when my printer arrives. let me know if there are tricks to getting it to work....

Thanks. I have the arduino USB plugged into my laptop for power. Arduinos have a variety of power supplies that you can use. The arduino program code is as simple as I could make it for dual axis tracking purposes. If you know about arduino programming, you can add the proper language to make it do whatever you want (in absense of light return to a certain position=sunrise). Too much for me at this point. Good luck and post if you make one. I'd like to see how it turned out.

I like your design a lot. What is powering the motors and arduino board? Do you have a separate power supply for the motors and board? I'm interested in using a similar design and was wondering how it powers itself to return to sunrise?

Can you also build a star tracker? =)