The Automatic Lawn Irrigation Network (Project ALIN) is a “smart” irrigation system which uses sensor analysis to control water flow to designated zones to only water plants when necessary. Different parts of a yard have different watering requirements based on plant life and exposure to the elements. We needed to detect these differences and independently schedule watering for each unique region. This was a collaborative effort between John Walter and myself.
- A single command station houses all schedule logic and provides a user interface.
Users can configure the system and do on-demand actions through a web interface, connecting over WiFi.
- The command station talks to some arbitrary number of controllers, remotely located, using XBee radios.
- Each controller gathers sensor data from any number of irrigation zones and reports that to the command station.
- The controller also opens valves to control irrigation when the command station sends an irrigation schedule.
The command station creates or updates an irrigation plan and sends start and stop times to the controller. At the prescribed time, the controller opens and closes valves connected to piping to deliver water to zones.
The command station’s evaluation of a zone’s irrigation schedule can be augmented by user preference and the number (and type) of sensors in use. Our minimum goal for this iteration of the project was to collect soil moisture information as use that for evaluation. Sensor collection for temperature, humidity, and brightness have also been implemented. Online weather data analysis continues to be a goal for a future version of this project.