The Problem

Fixed solar panels lose a significant share of their potential output simply because they sit at one angle while the sun moves across the sky all day. That gap between installed capacity and actual energy harvested was the starting point for my senior capstone project: designing a system that physically reorients a panel to keep facing the sun, on two axes, throughout the day.

Background

Before touching any hardware, I looked at how existing trackers solve this problem; comparing single-axis versus dual-axis designs, and light-sensing feedback versus fixed astronomical-clock control. From my analysis, a hybrid approach, combining astronomical-clock control and sensor driven approach with four light-dependent resistors (LDRs) arranged in quadrants around the panel which can continuously compare light intensity across each pair, then a microcontroller use that difference to know which way to turn the panel. For actuation, servo motors made sense for a small prototype, while linear actuators were the better fit once the panel and frame scaled up to full size.

I proved out that control logic on a breadboard first. An Arduino was wired to a motor driver module and the four-LDR sensor array, with the code comparing sensor pairs and driving the motors toward the brighter side until the readings balanced — the same logic that would later steer the full-size actuators. Running this on the bench let me tune the sensitivity and response before any physical structure existed, so mistakes were cheap to fix.

Prototyping

With the control behavior working, I built a small-scale mechanical prototype: a laser-cut frame with two servo motors giving pan and tilt movement, and the same LDR array mounted at the panel's corners. This stage answered the questions the breadboard couldn't — whether the frame geometry allowed full range of motion, whether the sensors read consistently once mounted on a moving structure, and whether the two axes interfered with each other mechanically. Testing this model surfaced adjustments to sensor placement and mounting that fed directly into the final build. 

The High Fidelity Prototype

Once the mechanism and control approach were validated at small scale, I scaled the design up and fabricated it in steel. The final frame was welded and painted, carrying the panel on two rotating joints driven by a pair of linear actuators for tilt and azimuth. A custom enclosure was fabricated to house the motor driver electronics and control wiring, and the whole system runs off a solar charge controller with a display and USB output, so the tracker can charge a battery and power small devices directly from the panel it's tracking with.

The completed unit was then tested end-to-end, checking that it tracks a light source accurately across both axes, holds position once aligned, and recovers correctly as the light source moves , with final adjustments made to sensor thresholds and actuator timing to tighten the response.

The result was a working dual-axis tracker that went from a bench-top circuit to a fabricated steel system, and the process behind it; sensing, small-scale validation, then full-scale build and test is really the story of how the design took shape.