homeassistant

Depends on where you live. Not open source but Ikea has one.

https://www.ikea.com/se/sv/p/knycklan-elektronisk-diskmaskinsavstaengning-20425724/

I built my own with an esp32 and esphome.

Esp32 runs a relay board which switches the 24v to my sprinkler valves.

Rachio is supposed to have a local API coming soon. The Smart Hose hardware is great quality and I’m happy with their app in the meantime. Waiting to see how they open the integration before I commit heavily.

I have one of these with normal sprinkler system valves. opensprinkler.com/. Works great with home assistant.

I made my own that used irrigation valves with a Zooz Zwave dry relay, with Home Assistant to control it. It was a giant pain to find and get everything hooked up right but afterwards it works well.

I’ve since found some zigbee-based irrigation valves in AliExpress that I’ll try out this summer. I think they’re about the same price as what I built per valve (considering all the parts and the time needed). I haven’t had a chance to try them yet as I got them at the end of last summer but they worked well in testing.

Something like this: https://a.aliexpress.com/_EyxaOkZ