Left LDR
Measures left-side light intensity.
Completed Project • May 2025
Arduino Solar Tracker
A single-axis solar tracking system that automatically aligns a solar panel toward the strongest light source using dual LDR sensors, an Arduino UNO, and servo-based position control.
Arduino UNOArduino C++LDR SensorsSG90 ServoFusion 3603D PrintingTinkercad
01
Project Overview
The Arduino Solar Tracker is a single-axis embedded system designed to maximize solar exposure by automatically orienting a solar panel toward the strongest light source. The project combines analog sensing, embedded programming, servo control, and mechanical design into a complete working prototype. The system was first validated through simulation before being physically implemented and tested.
02
Engineering Challenge
Problem Statement
Fixed solar panels cannot continuously face the sun, reducing the amount of solar energy they can capture throughout the day.
03
The Solution
To address the challenge, the project was designed around six engineering objectives that guided both the hardware and software implementation.
- 01
Detect sunlight direction using two LDR sensors.
- 02
Rotate the solar panel automatically using an SG90 servo motor.
- 03
Develop a reliable real-time embedded control algorithm.
- 04
Validate the design using Tinkercad simulation.
- 05
Build and test a complete physical prototype.
- 06
Document the entire engineering design process.
04
System Architecture
Two LDR sensors continuously measure light intensity. The Arduino compares both readings and rotates the servo toward the brighter direction until the solar panel is aligned with the light source.
Right LDR
Measures right-side light intensity.
Arduino UNO
Reads analog values, compares both sensors, applies threshold logic, and generates servo commands.
Servo Motor
Rotates the panel toward the brighter direction.
Solar Panel
Maintains maximum exposure to sunlight.
05
Hardware Design
The hardware was selected to balance simplicity, reliability, availability, and cost while satisfying the system requirements.
Arduino UNO
- Purpose
- Main embedded controller.
- Selection Reason
- Simple development platform with sufficient analog inputs and PWM outputs.
LDR Sensors
- Purpose
- Measure light intensity.
- Selection Reason
- Low-cost analog light sensing suitable for directional comparison.
SG90 Servo
- Purpose
- Rotate the solar panel.
- Selection Reason
- Simple PWM interface with adequate angular precision.
3D Printed Frame
- Purpose
- Support the mechanical assembly.
- Selection Reason
- Provides accurate sensor positioning and lightweight construction.
| Component | Purpose | Selection Reason |
|---|---|---|
| Arduino UNO | Main embedded controller. | Simple development platform with sufficient analog inputs and PWM outputs. |
| LDR Sensors | Measure light intensity. | Low-cost analog light sensing suitable for directional comparison. |
| SG90 Servo | Rotate the solar panel. | Simple PWM interface with adequate angular precision. |
| 3D Printed Frame | Support the mechanical assembly. | Provides accurate sensor positioning and lightweight construction. |
06
Engineering Decisions
Key engineering decisions made throughout the project and the trade-offs considered during the design process.
Two LDR Sensors
- Rationale
- A two-sensor configuration was selected instead of four sensors.
- Trade-off
- Lower cost and simpler implementation at the expense of dual-axis tracking.
Single-Axis Tracking
- Rationale
- Only horizontal tracking was implemented.
- Trade-off
- Simpler mechanical design while still improving solar exposure.
Threshold = 10
- Rationale
- Servo movement occurs only when the light difference exceeds a predefined threshold.
- Trade-off
- Reduces oscillation while maintaining responsive tracking.
SG90 Servo
- Rationale
- A lightweight servo motor was selected.
- Trade-off
- Simple integration with limited rotation range.
| Decision | Rationale | Trade-off |
|---|---|---|
| Two LDR Sensors | A two-sensor configuration was selected instead of four sensors. | Lower cost and simpler implementation at the expense of dual-axis tracking. |
| Single-Axis Tracking | Only horizontal tracking was implemented. | Simpler mechanical design while still improving solar exposure. |
| Threshold = 10 | Servo movement occurs only when the light difference exceeds a predefined threshold. | Reduces oscillation while maintaining responsive tracking. |
| SG90 Servo | A lightweight servo motor was selected. | Simple integration with limited rotation range. |
07
Development Journey
From concept to a fully functional Arduino Solar Tracker prototype.
- 01
Research
Requirements & planning
- 02
Simulation
Tinkercad validation
- 03
Assembly
Hardware prototype
- 04
Programming
Arduino C++
- 05
Integration
3D frame & wiring
- 06
Testing
Calibration
- 07
Final
Working prototype
08
Testing & Validation
The system was validated through simulation and physical testing to verify functionality, stability, and overall system performance.
Simulation
Passed- Validation Method
- Tinkercad
Prototype Assembly
Passed- Validation Method
- Physical Build
Servo Tracking
Passed- Validation Method
- Real-Time Operation
Threshold Calibration
10 Units- Validation Method
- Experimental Tuning
Mechanical Stability
Passed- Validation Method
- Frame Validation
System Demonstration
Passed- Validation Method
- Final Presentation
| Test | Validation Method | Result |
|---|---|---|
| Simulation | Tinkercad | Passed |
| Prototype Assembly | Physical Build | Passed |
| Servo Tracking | Real-Time Operation | Passed |
| Threshold Calibration | Experimental Tuning | 10 Units |
| Mechanical Stability | Frame Validation | Passed |
| System Demonstration | Final Presentation | Passed |
09
Results
The final prototype successfully met the project’s engineering objectives while demonstrating reliable embedded control, mechanical integration, and practical implementation.
Successfully tracked the strongest light source.
Validated the control algorithm through Tinkercad simulation.
Built a complete physical prototype.
Achieved stable real-time servo control.
Integrated embedded software with mechanical design.
Documented the full engineering workflow.
10
Gallery
Design, simulation, hardware implementation, and the final working prototype.
11
Lessons Learned
Key engineering insights gained throughout the design, implementation, and validation of the project.
Simulation Saves Time
Validating the control algorithm in Tinkercad before building the hardware significantly reduced debugging time.
Mechanical Design Matters
The alignment of the LDR sensors and the 3D-printed frame directly affected tracking accuracy.
Simple Solutions Win
A threshold-based algorithm achieved stable tracking without introducing unnecessary complexity.
System Integration
Integrating hardware, embedded software, and mechanical design proved more challenging than developing each subsystem independently.
Future Improvements
- Dual-axis tracking.
- ESP32 implementation.
- Real solar panel integration.
- RTC-based predictive tracking.
- Weatherproof enclosure.
- Wireless monitoring.
- Data logging.
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