Design and Implementation of a Low-Cost Dual-Axis Solar Tracker Using an Arduino Uno, Quadrant LDR Sensing and a 3D-Printed Pan-Tilt Mechanism

This paper presents the design and construction of a low-cost dual-axis solar tracker. Four GL5528 light-dependent resistors in voltage dividers form a quadrant sun sensor read by an Arduino Uno (ATmega328P), which drives two SG90 servos to orient a small photovoltaic panel in azimuth and elevation using a tolerance-band closed-loop algorithm. The control electronics are soldered on a general-purpose perfboard and the pan-tilt frame is 3D printed. The paper gives the architecture, pin assignment, control algorithm, bill of materials and a protocol for comparing the tracker with a fixed panel.