Design and Experimental Evaluation of an Affordable Dual-Axis Solar Tracker for Off-Grid Applications

This paper presents the design and experimental evaluation of a low-cost dual-axis solar tracking system for small-scale, off-grid photovoltaic applications. Unlike previous designs, the proposed system introduces a modern differential threshold control logic that combines an asymmetric dead-band and time-weighted averaging filter to suppress actuator jitter and minimize tracking error under rapidly fluctuating irradiance—an approach not commonly implemented in low-cost Arduino-based trackers. The hardware integrates carefully selected, low-backlash DS3218 servo motors and PTFE spacers to reduce mechanical hysteresis, enabling repeatable angular positioning with minimal overshoot. Over seven days of outdoor testing, the system maintained an average tracking error within ±2°, delivering a 30–40% increase in daily energy output compared to a fixed-tilt panel under clear skies. The total system cost remained under $200, and a transparent energy budget analysis—including actuator and conversion losses—was provided, which is rarely reported in similar studies. These results demonstrate that the combination of enhanced differential control logic and pragmatic hardware choices can achieve robust, reproducible, and cost-effective solar tracking suitable for decentralized and educational PV installations.