I'm thinking of building my own reticulation controller to drive an automatic watering system. Does anyone out there have a good circuit diagram? A simple 6 or 8 station control with adjustable timer and a 'GO' button would do nicely! Then I can push said 'GO' button and the stations would then come on in sequence for the selected time and automatically cycle until finished.
I would search for "sprinkler controller". Your system will need to have an MCU of some type with a display or LEDs plus an array of triac components that can switch the valves on and off. Most sprinkler and irrigation type valves operate off 24VAC.
You may want to investigate the OpenSprinkler project.