I'm thinking about taking this cheap 1.2VDC solar powered garden light's solar cell and making something I can hook up to my Arduino mega to record how much sun I get where I'm at. In theory I should be able to monitor the voltage coming from the solar cell on an analog input pin of the arduino. I don't anticipate the cell ever producing the 5VDC limit on the Arduino, but maybe I should add a voltage regulator as a protection measure, say if the cell short circuits.
What to do with the voltage, albeit tiny current, generated from the solar cell though? I could charge a backup battery for the house's Arduino Mega.