dr113j from instructables has decided that commercial garden watering controller didn’t give him enough flexibility to select time and operation modes, so he decided to build one. As a base he have chosen and Arduino with along with also his made Ethernet controller.
What controller has to do is to drive 12V watering solenoids. So simple transistor circuit is enough on a power side of board. There is also a DS1302 RTC chip used to track time. The rest is left for software where limits is your own imagination what, how and when you want to water your garden. And of course it is more fun when you can do this via web interface.