Irradiance Meter, I showed a picture of my friend Orris's solar panel set up for evaluation. I recently had a chance to visit and see the progress on this project. It's most impressive! Orris has been busy. Although not a exactly a microcontroller project, I think you'll enjoy seeing what a DIY-er can do on a large scale.
The array consists of 24 panels of 4' x 4' with a potential output of about 4 kW. The array features vertical tracking and will eventually include reflectors to direct more sunlight on to the panels. The panels are shown nearly fully elevated for the winter sun in the Seattle area (47° N latitude).
The solar array is nearing completion. It's been a long project for Orris, but the results look great!
This picture shows the complete array with the aluminum reflectors in place. They don't look shiny here as they are coated with frost for the first time this season.
Positioning of the array, which moves continuously throughout the day to achieve maximum insolation to the PV panels, is controlled by an Arduino and gear motors and a rack & pinion system. A GPS module provides date and time for use in the angle calculations.
The reflectors substantially improve the output of each PV panel without the expense of additional panels. A more detailed article with be forthcoming, including a discussion on the efficiency of the reflector system.