In-depth resources to create my own dual-axis solar tracker using 1 DC motor and 1 battery/power source

Thread Starter


Joined Sep 18, 2023
Hi all,

I'm quite new to electronics. I have a very basic understanding of DC circuits, but nothing too extreme, therefore I would like some help on how to create a dual-axis solar tracker using 2 LDRs, run off of a single DC motor, and 1 battery/power source (potentially looking into solar panels for power). I also do not want to do any programming yet, so purely wondering if this is possible with just hardware and components, no arduino.

I want to be able to have the "mounted" LDRs move (if looking top-down view) left and right & up and down as it tracks the suns movement

Where would be a good place to start? I know I'll need to test via a breadboard but will it be possible to use a breadboard for the end-project and not have to design and print a PCB?

I'm somewhat confident to make the wiring connections as necessary (hands-on stuff), but have a hard time understanding what components I need/how to find what I need (more theory-related stuff).

Hopefully it makes sense.



Joined Oct 2, 2009
Welcome to AAC!

I would not do solar tracking. The movement of the sun is very predictable everyday and over the whole year. I would just step the motors every 15 minutes.


Joined Aug 31, 2022
The mechanics are rather more complicated than the electronics and If you want a dual axis tracker you’ll need four LDRs and two (geared) motors.

For each axis the trick is to place two LDRs just behind the solar panel on opposite sides of the panel so that when the panel is directly facing the sun both LDRs are partially shaded by the panel but when the panel is slightly tilted one LDR is shaded, the other is receiving direct sunlight. You can use a comparator to compare the resistances but that is a bit brutal, it will make the motor continuously “hunt” - that means keep going back and forth, so using an op amp with some hysteresis would be better.

It would work okay but if you are seriously interested in a practical system I’d very much recommend incorporating a processor


Joined Jun 19, 2012
Basic solar tracking is not too difficult, it's dealing with the practical "edge conditions" that becomes difficult.
This is why an MCU based design is more practical.

How do you make it "reset" to the east in the morning?
What does it do under diffuse, overcast light?

This video shows my tracker concept, totally passive, no batteries, using two small solar cells for both power and sun sensing:
The two solar cells are mounted 90 degrees at the point, so the unit can receive light over 180 degrees,
this makes it able to recover and track back to the east just running on the "sky glow" in the AM.

The tracker just moves in the direction of the cell getting less light.

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