Picture of Solar Tracker in the Internet Cloud

This is a Solar Tracker. A full size, internet cloud connected, smartphone accessible Solar Tracker built mainly from 2x4s and plywood, employing wooden peg gears, recycled curtain poles, nuts, bolts and threaded rod. The solar tracker uses a home built electronic controller incorporating WiFi, stepper motor drives, accelerometer and magnetometer. The tracker was designed to drive a full size 90W panel in azimuth and elevation. The gears driving the tracker are wooden peg gears commonly used in the 16th century. The gears were designed using modern 3D CAD (Solidworks). Connecting the wooden peg gears to the internet cloud just seemed like the right thing to do. This is not a waterproof design – you will need to consider modifications to waterproof your derivative design.

The project includes mechanical mechanisms, web application, free/green solar energy, firmware, basic electronics, a microcontroller, accelerometer/ magnetometer, the Internet of Things, WiFi, 3D Modeling, CNC machining, re-use and basic woodworking. The Internet Of Things was enabled by the innovative Electric Imp -

The project started with a need to automate the irrigation of our raised vegetable garden. The purpose of the vegetable garden is to reclaim some semblance of self reliance on the veggi front. Adding a solar panel allows the vegetable garden to water itself in a self-reliant way. Adding a rain barrel collection system as a water source ramps the self-reliance up further and is an environmentally sound thing to do. 90W is certainly way more power than we need, but I’m sure over time I will find more things to connect. The rain collection system is documented in another Instructable A future instructable will document the irrigation system as time permits.

The need for solar tracking is well documented in the available internet literature and scientific journals so there is no need for me to repeat it here. There are many arguments for and against, but efficiency gains of up to 30% versus static installation make solar tracking attractive. You just need to make sure that your motive power needs are much less than the potential efficiency gain. The additional cost of a tracking solution is added to the overall cost of a solar system which increases the time to a positive ROI. But tracking does not need to be expensive – at least not for the home hobbyist with a small number of solar panels. The tracking accuracy requirements are not that high either. Using a micro-controller to control the tracking made it easy to control the tracking power losses by having the system operate in a low power mode for as long as possible, with only an occasional high power spurt to turn the motors a small amount. There are other ways to do solar tracking (optical sensors connected to simple circuits for example - "light followers"), but microcontrollers create opportunities for feature creep and you will learned a whole lot too. And learning is key.

Here's a short video to show the completed project in action:

Let's get started shall we?

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mgalas1 month ago

How did you connect the threaded nut for the vertical motion?

Moon_Watcher4 months ago

The idea of using an accelerometer plus a compass to sense the actual attitude of the panels seems interesting, is this idea of yours?, I'd like to know more about it. Have you formally published some work related with this idea?, do you have some reference to someone else who has worked with it?

MidnightMaker (author)  Moon_Watcher4 months ago

The only published data is this instructable. I have not seen another example of compass-inclinometer tracking but that doesn't mean that it's not out there somewhere. This is an original implementation as far as I know. The algorithm for determining the sun's attitude based on geographic location and time of day is open source.

2 x Nema23 just to follow the sun? Any "tweaked" 360º high-torque servo would do! You're going to use more power than what you will generate, that's not very green -- but you're not green anyway if you're using solar panels :-D

Besides the feat of mixing old technologies and newer ones, what applications can you foresee for this toy?

MidnightMaker (author)  ндогонят4 months ago

But what do you expect me to do with the box full of nema 23 stepper motors I got for free! :)

You seem to be confusing what I do for fun with professional product development. No-one would take the time to make wooden gears for a real world product.... but it was a lot of fun making them work! Projects are simply a way to keep my hands busy, my mind active and an opportunity to do what I want, when I want and how I want.... which is actually a rare experience in today's culture. Thanks for reading and taking the time to comment

You got the Nema23 for free? I'd love to have that kind of gifts :-D
I just said they're overkill if you have to pay for them when the Chinese servos (way smaller) or step motors (and linear gears, you should find that fun to design if you like to keep your mind busy).
I like the idea of the wooden gears, it's a change to all these 3D printed things, I just think an all-wood gimbal and a wooden gear but with smaller (and cheaper!) motors would make it reasonable to make for other makers to build it.

Good day!
Sir, do you think this servo would do of this project? Here's the link of the servo

Yeah, that's exactly what I meant, this is a 360º servo with torque, more than enough for the base (it's rotation only, not lift), and it is enough for the tilt if your panel is properly balanced and sheltered from the wind (beware the sail effect, but that's valid for a Nema23 too...). But isn't 1000PHP (~17€) a bit dear compared to China prices?

Yeah I think it is imported from china and sold it here in Philippines with fair price. Thank you for the reply sir. :)

jaykentchriss7 months ago

hi!.. after i downloaded your attached WebFiles.pdf, im wondering why i can't open it. here is the screen shot of the problem ... im hoping for your fast responce :)

MidnightMaker (author)  jaykentchriss7 months ago

Hi, the file is actually a zip file. Rename the file extension from .pdf to .zip and unzip it.

In the past, instructables didn't allow the uploading of zip files. They do now, so I guess I should go and fix all the old uploads :)

Thanks i opened it :) ... I have another question, it is possible to use an arduino uno or mega with ethernet shield instead of electric imp in this project? Because electric imp is not available in our country and if i will order it from the other country its shipment is very expensive. I am hoping for your responce :)

It's possibly much easier to redesign the whole thing with a Raspberry Pi / Galileo / Boogie Board (for the network and control part, install a webserver on the Raspberry Pi and connect directly to your home webserver with your phone) and an ATMega8/16 (or a home-made ATMega 328P/20 board) to control the servos. For the communication, you may prefer Serial (pin 2/3 of the ATMega, don't forget the Zener to protect the RPi!), I prefer I2C (don't forget the Zener either...) so I can add a lot of toys on the line (e.g. screen, joystick for manual override, etc.)

siqinie1 year ago
hi,can you please give a link of stepmotor ,there are so many of it ,i afraid of geting a wrong one,thank you.
MidnightMaker (author)  siqinie1 year ago
I used a Nema 23 Frame size bipolar stepper motor that has 256 of torque and 200 steps/revolution. Here are some links to motors that will work for this. THe exact motor was Vexta PK268-02A

i really like you project,it is so cool, and i tried to make one by myself,but i just lack tools and there are some problems i can not solve, so i want to ask is that possible to buy this from you,because i remember you said you might make a new one.

MidnightMaker (author)  siqinie1 year ago

Hi siqinie, shipping something like this is very difficult, and expensive. You can PM me directly if you want to discuss this further

thank you for your valuable advise,i am a chinese studying in manila,if in the future i can help ,maybe you can opt to contact me.
jmpm46191 year ago
Where is the best source to reach you?
MidnightMaker (author)  jmpm46191 year ago

Hi, I sent you my email address. Check your PM inbox under your instructables profile.

jmpm46191 year ago
How can I reach you?
jmpm46191 year ago
Yeah your right. Electric imp looks smaller. I think I'll opt for the electric imp. I am currently for a circuit designer. Are you available to help or if you could please direct me to someone who can.

I am interested in making a smart device for home automation.
MidnightMaker (author)  jmpm46191 year ago
Sure, I can help. Send me a PM with what you have in mind.
jmpm46191 year ago
I have found this device hopefully it is something to take into consideration. Let me know what you think.
MidnightMaker (author)  jmpm46191 year ago

It looks like a good device. But, it is larger than the Electric Imp, and I thought you were looking for something smaller.

jmpm46191 year ago
Is there one that is a bit more compact. I notice that a lot of these small smart appliances are using something that is much smaller. Any suggestions?
MidnightMaker (author)  jmpm46191 year ago

None that I know of. The two main competing products in this space are the Spark Core and the Electric Imp. They are similar in size. There is rumor that electric imp is working on a device that is 10% of the current size but the release timelines are not public as far as I can see. There are a lot of companies that make WiFi modules, but none of them provide a complete platform the way that Spark and Electric Imp are providing. The benefit you get is that you can run your code directly on the module - you don't need an additional microcontroller for most things. There are tiny USB WiFi modules available, but these will require drivers and an external microcontroller (raspberry pi) for example to be useful. If size is a gating factor for your solution, you are going to have difficulty finding something - let me know if you do as it will help me as well.

jmpm46191 year ago
Which component do you use to connect and let you control via app?
MidnightMaker (author)  jmpm46191 year ago
It's an electric imp.
evgen_ru1 year ago
I am sorry... but... Why internet? Only 4-photoresistors + cross-separator + AVR-controller :)
srai61 year ago
Solar tracker..ummm.. interesting stuff indeed. Being into a small sized organization, I had always had good guts for time management software and therefore had been using the one offered by Replicon Inc.Never had an idea about this stuff...really nice write up! Thanks.
Nice project, but does it need to be this complex? couldn't you just use one of the simple BEAM light-seeking head circuits, and get the same effect?
MidnightMaker (author)  mushroom glue1 year ago
Thanks for your comment. I did mention this in step 2.
You could have also placed it on an axis that points to the north star and then have a manual tilt adjustment off that axis that you change once every 2 or 3 weeks as the season changes. Then you rotate it with just one motor based simply on time, 15 degrees per hour. Or use a simple sun light tracker with 8 parts: 2 sets of 3 wide-angle LED's in series as a miniature "solar cell" (LEDs can generate electricity from light) and use the difference in voltage to turn on 1 of 2 mosfet transistors to turn a DC motor forwards or backwards. Or if you want 2 axis based on sun position, the math is a LOT simpler if you start with a polar axis. Just use the simple Wikipedia Sun declination equation for the tilt off the polar axis and 15 degrees per hour for the other axis. Eventually I'll do one of these instructables to show how I used $20 of aluminized mylar covering four $12 4x8 insulation boards to reflect sunlight into 2 north-side bay windows to heat 3,000 sq feet from 9 am until 9 pm (heat retention in the house, dropping from 77 F to 70 F by 9 pm). 10 kW of sun energy (20% loss from double pane windows) for about $200 total, 50 to 100 times cheaper than solar cells. Saved $500 last year with an oak tree blocking half the light. My support structure and axii were 4 door hinges on 2x4s. The LED's powering the mosfets are placed on the edges of the window. Reflecting sunlight into a window ("heliostat") has math that is a lot more complicated than sun tracking because you track half way between the target window and the sun.
MidnightMaker (author)  zawy1 year ago
Thanks for your input. I look forward to instructable. I really wanted to see what it would take mash centuries old gear tech with modern iPhone control and monitoring, and achieve a practical result. Someone has suggested that I remove the steppers in favor of water wheels to turn the gears. Gen 2!!!!
I did an instructable on my heliostat ideas and I'm thinking about using your method of gearing. See my user page, or rather
MidnightMaker (author)  zawy1 year ago
Nice project zawy and a real cost benefit. Thanks for sharing
that would be really lovely +_+
Ah. Sorry. I missed that. Sometimes Overkill is good for a laugh.
MidnightMaker (author)  mushroom glue1 year ago
And I learned plenty!
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