Single Axis Solar Tracker Control Prototype

Study Case Single Axis Solar Tracker Control Prototype on Solar Panels Based on Arduino Uno and LDR Sensor Michael Kurniawan (2018123456) University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, United States kurniaml@mail.uc.edu Abstract The increasing demand for electrical energy is not proportional to the dwindling fossil fuel reserves, making the use of renewable energy a strategic choice. One of the abundant renewable energy sources in tropical regions such as the United States is solar energy. However, conventional solar panels that are installed statically have limitations in absorbing sunlight optimally. This study aims to design and test a prototype of a single-axis solar tracker system based on Arduino Uno and Light Dependent Resistor (LDR) sensors to improve the efficiency of light energy absorption. The system is designed with two LDR sensors installed on the east and west sides of the panel, then connected to Arduino to control the servo motor as the panel's drive actuator. The test results show that the prototype is capable of tracking the direction of light with an average error of 2.9 lux (12.4%). However, there is a slight delay in response when the panel adjusts the direction of light, indicating the need for a more adaptive control system. Therefore, the integration of advanced control algorithms such as PID or Fuzzy Logic, as well as the use of sensors with faster responses, is recommended to improve system performance. This research proves that a simple solar tracker system can be an initial solution to improve the efficiency of small-scale solar panels. Keywords: solar tracker; single axis; Arduino; Servo; LDR Sensor MICHAEL KURNIAWAN 1 Study Case INTRODUCTION Electricity is an important commodity used in almost all economic sectors. With the increasing demand for electricity in the United States, utility companies such as Con Edison and PG&E are aggressively promoting energy efficiency programs for households, businesses, and government agencies. In the 21st century, the demand for electricity has increased rapidly, while global fossil fuel reserves are dwindling. Projections indicate a 70% increase in electricity demand between 2000 and 2030, especially in industrialized countries. Therefore, new sources of energy that are efficient and environmentally friendly are needed as the main source of electricity. Solar energy is one of the abundant renewable energy sources that can be utilized both radiatively and thermally to meet daily electricity needs. Unlike fossil fuels, solar energy will not run out because it comes from nature. Geographically, regions in the US such as Arizona, California, and Florida have fairly constant sunlight exposure throughout the year, making them ideal locations for solar energy utilization. However, most solar panels used are still static, so solar radiation absorption is not always optimal. Therefore, technology is needed that allows solar panels to adjust their position so that they are always perpendicular to the direction of the sun's rays. One solution is a solar tracker system. This system uses sensors to detect the highest light intensity and a microcontroller as a control center, so that solar panels can automatically move to follow the sun's movement from sunrise to sunset. The solar tracker system is designed to increase electricity production by adjusting the position of the panels so that they are always perpendicular to the sun. Based on previous research, various types of solar trackers can be implemented, using servo motors or linear actuators that are automatically controlled by microcontrollers such as Arduino. This single-axis solar tracker prototype was designed using Arduino Uno as a microcontroller, LDR as a light sensor, a 5V battery, a mini servo motor as an actuator, and a mini solar panel with a capacity of 5V connected in parallel. LDR was chosen because it is capable of reading the direction of the sun's movement from sunrise to sunset, even though its response is relatively slow according to the sun's movement. MICHAEL KURNIAWAN 2 Study Case RESEARCH METHOD The solar tracker system is designed with two LDR sensors to automatically change the position of the panel. The system uses a single axis where a servo motor moves the panel horizontally. Two LDR sensors are combined with a mini servo programmed on Arduino Uno to regulate the direction of rotation so that the panel can move optimally. System Block Diagram The control system on the solar tracker functions to control all components through a series of sensors. The single axis circuit uses two LDRs, each of which is connected to a 1 kΩ resistor before being connected to ground (-) and supplied with 5V (+) voltage. The Arduino Uno is programmed to initialize the pins as “HIGH” or “LOW” logic commands to activate or deactivate the output. Figure 1. System block diagram 1. 5V battery: Power source for Arduino. 2. LDR sensor: Detects light and provides output to the servo motor. 3. Arduino Uno: The brain of the control system, connecting software and hardware. 4. Servo motor: Moves the solar panel to follow the direction of the light. 5. Solar Panel: Absorbs light and converts it into electrical energi. 6. Arduino Monitor: Monitors the servo motor angle output. MICHAEL KURNIAWAN 3 Study Case Prototype Design Figure 2. Mechanical design of a single-axis solar tracker system Description: 1. East-facing LDR mount 2. West-facing LDR mount (West) 3. Servo as horizontal axis drive 4. Arduino as controller 5. Mini solar panel prototype The prototype is automatically controlled by an Arduino program that reads the conditions of both LDR sensors and adjusts the servo motor rotation to position the solar panel. MICHAEL KURNIAWAN 4 Study Case Flowchart Figure 3. System Flowchart The flowchart illustrates the control of a single-axis 5V solar panel with an LDR sensor: 1. Start: The system is turned on and initialized. 2. Measure Intensity & Angle: The light sensor reads the sun's intensity and sends the data to the microcontroller. 3. Input Data: The microcontroller analyzes the data and determines the optimal angle for the solar panel. 4. Sensor Detects: If light is detected, the servo moves in the direction of the LDR sensor; if not, the servo remains stationary. 5. Read Output: The Arduino monitor displays the angle and light intensity received by the LDR. 6. Stop: The system stops. MICHAEL KURNIAWAN 5 Study Case RESULTS AND DISCUSSION The results of the study show that the single-axis solar tracker system is able to follow the direction of light more effectively. Two LDR sensors are used to compare the intensity of light received, and the servo motor will move toward the sensor that receives more light. LDR Sensor Testing Table 1. LDR Sensor Test Results Table 1 shows that the LDR sensor performs well, with an average error difference of 2.9 lux and an error percentage of around 12.4%. The high error percentage in the first experiment (65%) was due to the very low light intensity, so that small changes resulted in a large error percentage. However, when viewed from the absolute difference, the error was only 1.3 lux. Overall, the LDR sensor is accurate enough to detect light intensity in small-scale applications. Overall Testing Figure 4. Single-axis solar tracker system prototype MICHAEL KURNIAWAN 6 Study Case Figure 4 shows the physical prototype of the developed single-axis solar tracker system. A mini 5V solar panel is mounted on a stand that can move to follow the direction of the light. This movement is driven by a servo motor that functions as the main actuator, receiving instructions from an Arduino Uno microcontroller, which acts as the control center. The Arduino obtains data from two LDR sensors placed on the east and west sides of the panel. These sensors detect light intensity from specific directions. When one sensor receives more light than the other, the Arduino processes this difference and instructs the servo to turn the panel toward the direction with higher light intensity. Test results show that the prototype is able to follow the direction of the light source according to the given movement. The servo motor moves the panel to be more perpendicular to the sunlight, proving that the system functions according to its main purpose, which is to increase light absorption compared to static panels. However, testing also revealed a delay in response when the panel adjusted its position. Although the panel ultimately followed the movement of light well, the relatively slow response time indicated the limitations of the system. This condition was influenced by the characteristics of the LDR, which has a slow response, as well as a simple control algorithm that only compares the intensity of two sensors without a predictive mechanism or error compensation. Although the system performance is adequate for experimental applications, it is not yet fully optimized for applications that require fast response times. These findings form the basis for the development of a more intelligent control system, for example by adding a PID Controller, Fuzzy Logic, or Model Predictive Control (MPC), so that delays can be reduced, servo stability improved, and angle adjustments made more precise. This evaluation shows that the prototype not only functions as designed, but also provides a basis for improvement so that the system can evolve from a simple experiment into a more applicable solution in solar energy utilization. MICHAEL KURNIAWAN 7 Study Case CONCLUSION Based on the results of the design, implementation, and testing of the Arduino Unobased single-axis solar tracker prototype and LDR sensor, several conclusions can be drawn: 1. The developed system is able to follow the direction of light well. The solar panel can adjust its position to be nearly perpendicular to the light source, so that solar energy absorption is more optimal than with a static panel. The sensor test results show an average error of 2.9 lux with a percentage of around 12.4%, which is sufficient for small-scale applications or laboratory experiments. 2. Although the system functions as designed, there is a delay when the panel adjusts to the direction of light. This delay causes the panel's movement to not always be real-time, even though the panel still follows the highest light intensity. This phenomenon is caused by the slow response of the LDR sensor and a simple control algorithm based on light intensity comparison. Overall, this study proves the potential of a simple solar tracker system to improve solar panel efficiency. Although there are still limitations in the form of response delays, the results of this study can be used as a basis for developing more complex control systems in future research. With the development of advanced control algorithms, the use of fast-response sensors such as photodiodes, and the integration of the Internet of Things (IoT) for real-time monitoring, this prototype has the potential to be applied not only on an experimental scale but also in broader renewable energy applications. MICHAEL KURNIAWAN 8 Study Case REFERENCE MICHAEL KURNIAWAN 9