I searched old posts, there doesn't seem to be any good zwave rain sensors.
Most i seen are ones where I have to wire it up to its own hub.
Can these be used for rain detection?
https://www.smarthome.com.au/aeotec-z-wave-water-sensor-6.html
https://www.smarthome.com.au/fibaro-z-wave-flood-sensor.html
It seems to pick up small amounts of water. So should be sensitive enough?
Cheers
Rainwater is likely to cause a lot of corrosion to a standard leak sensor. And they aren't really designed to be wet "often".
If I were doing it, I'd use a sprinkler/irrigation system type rain sensor. Note that all the ones I've used in the past suck after a few years (the sun bakes them, they get clogged and start sticking, etc) but if you have relatively easy access to it they're not horrible. Wire it up to a z-wave contact/door sensor with support for dry contacts to interface it to the rest of your HA.
https://www.rainbird.com/products/rsd-series-rain-shut
so that rainbird one you've used in past?
would need every 6 months declog etc?
We have used the rainbird sensors.
Normally we get 2-3 seasons from one before it gets clogged. It depends on how many trees you have around, etc. They get brittle due to sun too. They're decent sensors for the money.
so means have to buy new one after 3 seasons?
or just unclog and it'll work for few years?
The shell getting brittle under sun shouldn't be a problem. I have a area that will catch rain but has no sun.