I'm working on a small robotics project and one of the things I've been trying to consider on self monitoring is how to measure how effective the solar is at any given moment as well as what areas are better for solar. In effect, if the robot is autonomously roaming the house, did it get more light in position X or position Y? I haven't programmed it yet to be smart enough to charge itself when the batteries are dying, but thats where this is eventually going to lead, just baby steps for now.
My problem is, I'm a programmer who's fell in love with arduino but still really learning the hardware side. Someone recommended measuring my solar panel output which sounded great, and I saw a thread here that looked similar to what I wanted to do. My only problem is, I don't know how to figure out what resistors I'd need.
Here's my setup, my arduino is being powered over USB, which comes from a 12v battery/solar controller/solar panel.
The solar panel is a 12v 5.2w panel.
For all practical purposes for my project, the number can be almost anything, as long as sunlight makes a higher number and darkness makes a lower number. I just want to make sure I don't fry my board!!
I really appreciate any help that anyone can send my way.