For more complex (multi-zone) systems a controller would be inside and the low-voltage valve manifold outdoors (24 volt). On a simple single system they do have battery powered valves that screw on the hose-bib valve. Even simpler is a mechanically timed valve that you turn to run for a set time, but that you have to remember each time and can't be gone for a week.
On mine the garden is zones of the sprinkler system. Just instead of sprinklers a pipe with a regular hose-bib valve is set up. A pressure regulator drops the pressure to 15 psi and 1/2" plastic line runs around the garden. 1/4" inch lines get added to the 1/2" main to run around to the vegetables and a few potted plants. 1/4, 1/2, and 1 gallon per hour drippers proportion the amount of water over time so the whole set gets run for a set time. Right now 1 hour, but that will increase a bit over the summer.
Saves time best used for pruning and the weeds and nothing dies because I'm gone or just forgot.
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On mine the garden is zones of the sprinkler system. Just instead of sprinklers a pipe with a regular hose-bib valve is set up. A pressure regulator drops the pressure to 15 psi and 1/2" plastic line runs around the garden. 1/4" inch lines get added to the 1/2" main to run around to the vegetables and a few potted plants. 1/4, 1/2, and 1 gallon per hour drippers proportion the amount of water over time so the whole set gets run for a set time. Right now 1 hour, but that will increase a bit over the summer.
Saves time best used for pruning and the weeds and nothing dies because I'm gone or just forgot.