Design and functional verification of an Arduino-based single-axis solar tracking prototype with environmental monitoring

Abstract

This study presents the design, fabrication, and functional verification of an Arduinocontrolled single-axis photovoltaic (PV) tracking prototype that monitors ambient temperature, relative humidity, and rain status. Two light-dependent resistors (LDRs), separated by an optical divider, generate a differential light signal for closed-loop orientation control. An Arduino Uno commands incremental single-axis movement through a microstep driver and stepper motor until the LDR difference falls within a prescribed deadband. A DHT11 sensor, a rain-detection module, and a 16×2 I²C liquidcrystal display provide environmental information. Outdoor functional trials at SLIET, Longowal, confirmed differential-light response, incremental sun-following motion, cessation of commanded movement near balanced illumination, sensor and display operation, and the detection and display of a controlled-wetting condition. Visually observable mechanical play and reduced LDR discrimination under diffuse light were noted. The study establishes functional integration rather than an improvement in energy performance because simultaneous measurements of irradiance, PV output, angular error, and actuator energy consumption against an identical fixed panel were unavailable. The ideal relation L(%) = 100[1 − cos(i)] is consequently used only to explain direct-beam geometric loss. The resulting platform provides a compact experimental basis for the comparative evaluation of fixed and tracked PV modules and for the refinement of sensing and control strategies.