How it works

Moisture is measured as variable voltage current between the two prongs of the moisture sensor and the data is then sent to one of the Arduino’s analog input pins. The onboard processor analyzes the reading before sending digital signals to the servo, which is connected mechanically to the wind chimes.

The wind chimes themselves are stacked into two levels — at the top are the resonating, un-dampened “wet” chimes, and at the bottom are the dampened “dry” chimes. The servo is attached to an arm that raises and lowers the wooden knocker to activate the wet or dry chimes.

Currently, this is a binary system that “listens” for the moisture level in the soil to reach a predetermined threshold and switches chimes when that threshold is crossed. In an expanded version of this project, there might be many chimes of different timbres and each one would be controlled by an individual plant in the garden. Because plants drink at different rates, every time an observer walks through their garden they will be presented with a unique “symphony of chiming.” Furthermore, as one becomes accustomed to the unique sonic signatures of each plant, they can know simply by listening to the aggregate, which plants need water. In this way, the server can “tune” their garden to keep it in harmony.