Two Axis Solar tracking system

Thread Starter


Joined Jan 6, 2014
Dear Friends,

I am planning to design two axis solar tracking system using pic controller (like PIC16F877A), LDR and two DC motors.

I will compare voltage of two LDR for one DC motor rotation (Either in reverse or forward) and other two LDR for second DC motor rotation through L293D driver circuit.

I am planning to do programming in MPLABX developing tool.

I want some suggestion regarding reliability, accuracy, performance, hardware requirement etc.

Plz suggest me for that.


Joined Apr 24, 2011
<two cents>
The sun moves "left to right" every day, but "up and down" over a full year. I would ditch the "up and down" sensor for a calendar and pray the "left to right" sensor doesn't go off chasing rainbows on cloudy days.

A solar array is obviously placed out doors. In the open. Exposed to ALL the elements. It needs to be firmly mounted for the highest level of wind it may ever experience. Thus the motor and all mountings must be very strong.

I have never seen a large commercial system where any tracking is used. Not once. They simply orientate the system for the average sun angle for the average day and lock it down tight.
</two cents>


Joined Feb 24, 2006
What will the algorithm be to move the motors in response to an increase in light intensity? How about a decrease like a cloud or a thunderstorm? I don't think you have thought this through. Will this system use more energy than it captures by optimizing the position of the array?


Joined Apr 5, 2012
With a clock, calendar, and map the location of the sun in the sky is completely predictable. Why not just write that into your code and ditch the sensors?


Joined Feb 24, 2006
How would you avoid the accumulation of time and position errors? How would you justify the expenditure of energy to return the array to it's initial position between sundown and sunup?


Joined Apr 24, 2011
You can mount lots of panels (up to 3kW) on a pole, and such installs allow attachment of a tracker. However, as panel prices go down, the cost of the tracker cannot really compete with the cost of extra-panels.[/QUOTE]

These seem to have but a single manual adjustment for seasonal (what I termed "up and down") adjustments. Nothing says motor driven.

AltStore said:
"Seasonal adjustability for maximizing electrical production is provided by six different tilt-angle settings and is a single person operation."
Hey, they might exist for smaller instalations. But as Parabravo correctly points out there ain't no such thing as a free lunch (you have to power the motor too).