Future things to work on / develop on this project include:

1) A purpose built device with a custom PCB - this will have a much lower cost (possibly well under $20 cost), and could add small features such as a battery, which could re-charge from the 24VAC power line when running, and contain its own antenna.

2) Custom phone App to access features / states of the RainBuddy

3) An inline current meter - this would allow the RainBuddy to most probably figure out the watering schedule, number of zones, and record this. It could then modify each zone independently, shortening the water times if it hasn't been that hot, for example, and even notify the user if their schedule doesn't match the recommended local schedule.