Building a solar tracker system involves designing a mechanism that adjusts the position of solar panels to follow the sun's movement, maximizing energy capture. Here’s a step-by-step guide to building a **dual-axis solar tracker** (which tracks both azimuth and elevation):

Components Required
1. Solar Panel(s) – The photovoltaic module to be tracked.
2. Microcontroller (Arduino, Raspberry Pi, ESP32, etc.) – For processing sensor data and controlling motors.
3. Light-Dependent Resistors (LDRs) or Photodiodes (4x) – To detect sunlight direction.
4. Slewing drive with 24V gear motors (2x) or stepper motors + drivers – For adjusting panel position (one for horizontal, one for vertical movement or one for both vertical and horizontal movement).
5. Mounting Structure – A sturdy frame with rotational joints.
6. Voltage Regulator (if needed) – To power the microcontroller and sensors.
7. Resistors (for LDR voltage divider circuits).
8. Battery (optional) – For powering the system when grid power is unavailable.
9. Jumper Wires & Breadboard/PCB – For circuit connections.

Step 1: Mechanical Assembly
1. Build the Frame
- Construct a base that allows 360° horizontal rotation (azimuth tracking).
- Attach a tilting mechanism for vertical adjustment (elevation tracking).
- Ensure the structure is rigid and weather-resistant (use aluminum or stainless steel).

2. Mount the Solar Panel
- Fix the panel to the frame using brackets.
- Ensure the panel can rotate smoothly without obstruction.

Step 2: Sensor Setup (Sun Detection)
1. Place 4 LDRs in a cross pattern (North, South, East, West) on the panel edges.
- Cover them with small tubes to improve directional sensitivity.
2. Wire the LDRs in a voltage divider circuit:
- Each LDR connects to a resistor (e.g., 10kΩ) to form a divider.
- The output goes to the microcontroller’s analog pins.

Step 3: Motor Control
1. Horizontal (Azimuth) Motor – A servo or stepper motor rotates the base left/right.
2. Vertical (Elevation) Motor – Another servo adjusts the panel’s tilt angle.
3. Connect Motors to the Microcontroller
- Servos: Use PWM pins (e.g., Arduino `D9`, `D10`).
- Steppers: Use motor drivers (e.g., A4988, ULN2003).

Step 4: Programming the Microcontroller
1. Read LDR Values
- Compare the readings to determine the sun’s position.

2. Adjust Panel Position
- Move motors to balance LDR readings (equal light on all sensors).

3. Add Time-Based Tracking (Optional)
- Use an RTC (Real-Time Clock) module for pre-calculated sun positions.

Step 5: Power Supply
- Use a small battery (12V) or a solar-charged battery to power the system.
- If using the tracked solar panel itself, ensure voltage regulation to avoid microcontroller damage.

Step 6: Testing & Calibration
1. Test in sunlight and adjust motor speeds/LDR thresholds.
2. Ensure smooth movement without vibrations.
3. Weatherproof the electronics (use enclosures).

Alternative: Single-Axis Tracker (Simpler)
- Track only east-west (horizontal) movement.
- Requires 1 motor and 2 LDRs.

Advanced Options
- GPS + Astronomical Algorithm – For precise sun position without LDRs.
- Machine Learning – Predict cloud movements for optimal tracking.