Here's a idea for you that I and others could use. I have a swimming pool, and I need a device that will float, sample the water, and disperse the proper amount of chemicals into the pool as needed. Oh, It needs to run its routine at night and have a docking station it hides in. Kind of like those vacuum cleaners that you see.
It could charge via solar.
I pay a pool guy right now to do it. You figure even if the device cost me a few hundred dollars. Thats cheaper than 6 months of pool service and that doesnt even include the cleanings