I have a container garden in the yard with numerous drip irrigation emitters. There's nothing terribly Ardiuno specific about actuating a valve, so pretty much any system would work, doesn't have to be arduino. I was unable to find all the parts I'd need cheaper than a COTS system around $40.
Probably your best bet would be a barrel (rain barrel?) full of water with a bubble lift (think old aquarium under gravel filter design) Then turn on the aquarium air pump for 15 minutes a day or whatever. This abstracts your problem from a plumbing mystery to merely turning a low wattage AC outlet on and off. Perhaps via a SSR or a commercial X10/insteon/other system. If the air pump and other electrical gear is mounted above max water level, no possibility of mixing water and electricity exists, just like a proper aquarium design. On the other hand depending on relative heights you might be building a siphon which will empty the whole bucket in one run, could be an issue.
Aside from the siphon thing, the barrel design also means the inevitable malfunction will not result in a flood over 55 gallons, and an air-lift obviously isn't damaged by running dry.
I have a container garden in the yard with numerous drip irrigation emitters. There's nothing terribly Ardiuno specific about actuating a valve, so pretty much any system would work, doesn't have to be arduino. I was unable to find all the parts I'd need cheaper than a COTS system around $40.
Probably your best bet would be a barrel (rain barrel?) full of water with a bubble lift (think old aquarium under gravel filter design) Then turn on the aquarium air pump for 15 minutes a day or whatever. This abstracts your problem from a plumbing mystery to merely turning a low wattage AC outlet on and off. Perhaps via a SSR or a commercial X10/insteon/other system. If the air pump and other electrical gear is mounted above max water level, no possibility of mixing water and electricity exists, just like a proper aquarium design. On the other hand depending on relative heights you might be building a siphon which will empty the whole bucket in one run, could be an issue.
Aside from the siphon thing, the barrel design also means the inevitable malfunction will not result in a flood over 55 gallons, and an air-lift obviously isn't damaged by running dry.