Construction of a Solar Tracker Using Optical and Ultrasonic Sensor by Internet of Things for Control and Monitoring on the Horizontal Axis

This preprint presents the design, construction, and experimental evaluation of a horizontal-axis solar tracking system that combines optical sensing, ultrasonic position feedback, linear actuation, and Internet of Things (IoT)-based control and monitoring. The optical tracking subsystem uses light-dependent resistor (LDR) sensors to estimate the direction of maximum solar illumination, while the ultrasonic subsystem provides mechanical position feedback for the tracker. An IoT-enabled control architecture integrates solar-position information, sensor measurements, actuator commands, and remote monitoring into a unified tracking and monitoring system. The proposed system is evaluated using solar-position information for Karaj, Iran under clear and cloudy atmospheric conditions. The results indicate that both optical and ultrasonic approaches can follow the reference solar position under clear conditions, while ultrasonic position feedback provides a more stable tracking alternative under cloudy conditions, where diffuse and scattered radiation can affect optical sensor measurements. The work demonstrates a practical and low-cost architecture for horizontal-axis solar tracking that combines physical position feedback with networked control and monitoring. The study also identifies future research directions, including direct electrical energy-yield comparison, actuator energy consumption, statistical analysis of tracking error, long-term reliability assessment, and comparison with fixed and alternative tracking configurations. This record contains the preprint manuscript and is intended to support research dissemination, citation, reproducibility, and subsequent peer-reviewed publication. This work is provided as a preprint and has not been peer reviewed at the time of deposit.