Using Arduino to water my plants, consists of an Arduino, Moisture sensor, Solenoid valve and something to drive the solenoid valve.
http://www.ebay.com/itm/282014326455?_trksid=p2057872.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT
http://www.instructables.com/id/Controling-a-solenoid-valve-with-an-Arduino/
http://www.ebay.com/itm/322183448637?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.com/itm/271700215191?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.com/itm/201537960316?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Setup:
Arduino, analog inputs A0 and up for sensors measuring moisture.
Digital output D2 and up is used to control solenoid valves with the help of the N-channel mosfets.
Digital output D12 is used to power up every moisture sensor before reading.