I was thinking an old wrt54g running something like ddwrt to base a basic two or three valve controller. You wouldnt have a screen though. Guess you could add one of the ddwrt screen hacks.

the team created customized sprinkler devices that allowed them to see and analyze water flow. The sprinklers were submerged in water within a system that could control the inflow or outflow of ...

What to do once you have a sprinkler system installed on your property: buy a sprinkler control system or make your own? The latter, obviously. [danaman] was determined to hack together a cheap ...