This is a simple arduino project for a soil moisture sensor that will light up a LED at a certain moisture level. It uses Arduino Duemilanove microcontroller board. Two wires placed in the soil pot ...

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. Anyone interested in creating interactive objects can “play” with Arduino! Described ...

Don Howdeshell, of Don's Projects, details the entire setup, from start to finish, on his blog. He even provides the wiring diagram for his controller and the config file for his lights.