Building a Better Controller for Eco-Worthy Solar Trackers
Eric Tischer built his own custom controller for his Eco-Worthy solar tracker.
You may have noticed that the sun moves across the sky throughout the day and that means that stationary solar panels spend most of their time outputting less power than they could. Therefore, many people turn to motorized solar trackers that ensure the solar panel is always getting optimal sun exposure. Eric Tischer bought an Eco-Worthy solar tracker for that purpose, but found its controller to be lacking. So, he used a microcontroller development board to build a better controller.
The controller that came with the Eco-Worthy solar tracker wasn’t terrible, but Tischer was unhappy with the overall experience. There were a few nagging issues, including the controller’s tendency to get confused about the current position of the sun, causing it to start a searching routine—particularly irritating when the motor is quite loud.
Tischer’s solution was to design and make his own controller that would give him complete control over the system, including tracking behavior. He built it around a ESP32-based development board with a few key sensors. First, there are two light sensors facing east and west. By checking their relative readings, the controller can determine if it has optimal light or if it needs to move. The second is a mercury tilt switch mounted on the solar panel. When the panel is at its extreme, that switch closes and the controller knows the panel is in its home position.
The ESP32 controls the motor through an opto-isolated relay module and displays status information on a basic 4×20 character LCD screen. All of that hardware resides inside of a weatherproof junction box mounted on the solar tracker’s stand.
The great thing about this solution is that Tischer has control over every aspect of the tracker’s operation. If he ever finds that it isn’t acting as he hopes, the fix is as simple as a code tweak and firmware update. But the preliminary firmware is well-considered and should work well, as it takes into account potential issues (like cloud cover) and the predictable nature of the sun’s movement.
However, the Eco-Worthy solar tracker only has a single motorized axis. That’s fine for operating throughout a day or week, but the suns’ angle also changes with the time of year. This solar tracker has a second manually operated axis for that reason, Tischer just have to move it once a month or so.
