Hi, my name is Viktor. I have made my solar hot water pump controller based on Arduino. And it is free. Here are the instructions
Hot water solar controller. Solar controller with your own hands. Part 1. and brief project description
House4u solar project - make hot water solar controller DIY! My motherlang is not English, so maybe translation is not so good
If you have any questions about my hot water solar system or my controller - i may answer and explain here.
My controller
My solar system
