SunTracker2 Revision 3

The Suntracker project develops a photovoltaic (PV) solar tracking controller. Pictured above is the revision 3 prototype. PV solar trackers control the PV panel direction to keep the panel perpendicular to the Sun, maximizing the power output. The power output difference for a fully aligned panel is reported to be in a range of 15~40%, which would be substantial.

Code and build details are in the FM4DD Github Repository, and in the Hackaday Project Repo.


The goal is a self-orienting dual-axis, scheduled, Arduino-based solar tracker. I want to control PV panel orientation for both Elevation and Azimuth angles (dual-axis), based on the calculated solar position of a PV systems specific geographic location and time (scheduled).

Working under space, cost and time constraints, the prototype development is done on a small scale model. Eventually, I want to control and optimize the orientation of Mini-PV systems.

Suntracker2 R3 implements single axis motor control.

Functional Design

In order to clearly understand and validate the sun tracking function, a 32 dual-color LED ring represents the horizon with north, sunrise and sunset indicators. A green indicator displays the suns daily movement over time. The optional NEMA stepper motor is used to develop the motor control code for the solar panel horizontal alignment.

Board Components

Board Layout

The solar position data gets calculated off-system in advance, and saved into a micro SD card. The pre-generated daily sun position files are then read by the Arduino MKR Zero microcontroller through the onboard card reader. The astronomical calculations of the suns position require sufficient CPU power, and are taxing on Microcontrollers.

At the moment I am using a sun position dataset that covers two years of operation, and uses approx. 20MB in size (46 MB with additional debug data). I wrote the “suncalc” tool to pre-calculate the data set files for a specific location, on a Linux PC.



Watch the video Suntracker2 Revision 3 Youtube functional demo

Code and Resources

FM4DD Github Repository Hackaday Project Repo