Keep Your Lawn Lush and Green with a Fully Automated Irrigation System

As Sebastian Stacks notes, there are plenty of projects out there that automate irrigation. This normally means activating a single valve to turn the sprinklers on, but per a limited water supply, he wanted to be able to run different sprinklers at different times of the day. He also wanted to be able to water each zone of his irregularly shaped lawn for different periods of time to soak it evenly.

These challenges meant that a single valve just wouldn’t do, so he instead set up a system of six Gardena 24V magnetic valves that control the individual watering zones, along with a seventh main valve as a safety in case anything went awry. An eight-position relay bank triggers each of the seven valves, plus another “top secret” function that he doesn’t reveal in his write-up.

An Arduino Nano 33 IoT module is implemented to control the relays, which takes input over MQTT from an OpenHAB installation. Additionally, there's a small OLED display with two buttons for manual control, useful when Staacks is on vacation and needs someone else to handle things. While his blog post isn’t meant as a step-by-step how-to, it provides a good overview of the system and code is available on GitHub if you want to try something similar yourself!