This project is designed for educational purposes. It will be used for demonstration to students in order to have a first touch with solar trackers and photovoltaics.

The project is related to renewable energy and specifically photovoltaics. A dual axis solar tracker with photovoltaic was designed in order to follow the sun during the day. Photovoltaic powers the solar tracker (no external source needed).

To track the sun, I used four LDC sensors and Arduino compares the data from them to rotate the panel in the direction with the most sunlight using two DC motors (one for each axis) and motor driver.

LDRs Motor Driver

There is a remote control with an auto/manual switch, single axis/dual axis switch and four buttons. While the first switch is turned to manual, you can manually rotate the panel using the four buttons (clockwise-anticlockwise in horizontal and vertical axis). While this switch is turned to manual, we have auto tracking of the system, single or dual depending the second switch.

EXPANDED TECHNICAL DETAILS

Scaling up a solar tracker to handle a heavy pane of glass outdoors introduces significant physical engineering challenges. This 35W Solar Tracker uses robust components to move significant weight, which can increase the power yield of a solar panel by over 30% compared to a fixed installation.

Worm-Gear Motors (Self-Locking)

Why not use large stepper motors? A heavy solar panel acts like a sail in the wind. A stepper motor requires constant, significant electrical current just to hold its position against this force.

• The solution is to use 12V DC Worm-Gear Motors (similar to automotive windshield wiper motors).
• The unique geometry of a worm gear means the motor can turn the output shaft easily, but the heavy solar panel cannot physically back-drive the motor. Once the motor stops, the panel is locked incredibly tight, requiring zero electricity to hold position.

The Limit Switch Imperative

A small servo has built-in rotation limits. A powerful 12V DC motor does not. Without safeguards, it will spin until it destroys the mechanical structure.

1. You must install Heavy-Duty Limit Switches (Microswitches) at the physical extreme ends of both the horizontal and vertical rotation paths.
2. The Software Interlock:

if (analogRead(LDR_East) > LDR_West) {
   if (digitalRead(Limit_East) == LOW) { // Is it safe to move?
       DriveMotorEast();
   } else {
       StopMotor(); // Hit the limit, STOP!
   }
}

3. This code creates a hard software interlock, preventing the Arduino from commanding the motor to move beyond its safe mechanical boundaries.

System Components for Heavy-Duty Operation

• Microcontroller: An Arduino Mega or Uno for logic and sensor processing.
• Sensors: 4x LDRs (Light Dependent Resistors) mounted in a cross pattern to detect light intensity from each cardinal direction.
• Motor Drivers: BTS7960 43A Motor Drivers are essential to handle the high amperage spikes and continuous current required by heavy DC gear motors.
• Actuators: 12V Automotive Wiper Motors or equivalent worm-gear motors.
• Power & Structure: A 35W or 50W Solar Panel to power the system, mounted on a robust steel or aluminum frame.