Solar power is a fantastic resource: clean, abundant, and renewable through to a timescale long enough that humanity probably won't have to worry too much. Harnessing it, though, can be complex: while it's entirely possible to simply strap a solar panel or two to a surface and hope for the best, peak efficiency is only obtained through mounts which automatically track the sun - mounts which are, usually, rather expensive. Bruce Helsen's solution? Building his own, powered by an Arduino Mega microcontroller.
Created as part of his graduate thesis for a degree in automation engineering - giving him, admittedly, something of a leg-up in the project above and beyond many hobbyist makers - the rig fits two 150W 12V solar panels for a 300W peak output and provides three main features: it automatically turns to track the sun throughout the day, ensuring the panels are always properly aligned to maximise sunlight exposure; it tracks the energy generated by the panels, listing the output on a built-in liquid-crystal display; and it transfers these figures to a remote server via a low-cost ESP8266 Wi-Fi module for analysis and logging.
Considering its functionality, Bruce's creation is surprisingly simple: four light-dependent resistors (LDRs) are set up in a cross arrangement to provide a bearing for peak sunlight, which is used by the Arduino Mega to shift the panels using a pair of 12V linear actuator motors. Other hardware used is either for safety - such as an end-stop switch to prevent the actuators pushing the rig beyond its limits - or to track or make use of the solar power itself, which is stored in batteries for later use.
While Bruce describes his write-up of the project on Instructables as more of a stepping-off point for anyone interested in building their own solar tracking system, his documentation is impressively thorough - including the thesis itself and a presentation on the topic.
The features of this solar tracker are: solar tracking, making sure the solar panels are aligned to the sun as long as possible; energy monitor, measures the voltage and the current generated by the panels and calculates the generated Power and Energy; data logging, sends the data from the energy monitor into the cloud of ThingSpeak; also there is an LCD to display the values of the energy monitor.