Hey everyone, I wanted to share a cool hack I came up with to make my Rainbird irrigation controller smarter using a Shelly 1. I’ve been dealing with this issue where the irrigation system would run even when it was raining or too windy, which was really frustrating. After some tinkering, I found a way to integrate it with Home Assistant to add some smart features. Here’s how I did it:
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The Problem: The Rainbird controller had a built-in rain sensor, but it was unreliable. I wanted a system that could pause watering if it was raining or too windy and also reschedule if it missed a watering day.
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The Solution: I connected a Shelly 1 to the rain sensor terminals. This allowed me to simulate the rain sensor’s open/closed circuit using Home Assistant. When the Shelly is on, the controller thinks it’s dry, and when it’s off, it thinks it’s raining. This gave me full control over the irrigation system through Home Assistant.
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Integration with Home Assistant: I set up automations to check the weather using OpenWeatherMap. If it had rained more than 20mm in the last two days or if the wind speed was above 20 kph, the system wouldn’t water. If it missed a watering day, it would try again on the backup day.
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Results: This setup has saved me a lot of water and hassle. The system now waters smarter, not harder. I also tied in my drip watering system for potted plants, which only runs if there hasn’t been enough rain. It’s been a great project, and I’m really happy with how it turned out!
If anyone has questions or wants to try something similar, feel free to ask. I’d love to hear if others have found creative ways to improve their irrigation systems. Cheers! 
