I have a couple of Fibaro Smoke detectors at home. In case of an alarm I was hoping the smoke detectors could alarm each other and have all sirens go off.
Although when setting up a flow there’s no way to choose a “then action” for the smoke detector. Is this because they are battery powered and not polling statuses that often?
What options do I have? Buy extra sirens? Use Sonos speakers (are they reliable in case of fire)?
Exactly. What you need if battery powered is a FLIRs Device.
Hmm, OK. I tried Google it but couldn’t find much. What is it? Software or hardware? Is it compatible with Fibaro smoke detectors?
FLiRS (Frequently Listening Receiver Slave)
What you are trying to achieve is not possible as fibaro smoke sensors are asleep 99.9% of the time to send signals by other devices.
This has been answered several times already on the forum.
There is currently only 1 brand that made smoke sensors with flirs (what osorkorn is talking about) that I know of at least (I did forget the brand though 
)
You can use siren (battery or main powered), but battery siren is not so reliable in my case (Vision siren), because it drains batteries quite quickly. If you have Sonos, then playing Soundboard sound over it is possible as well. You can use also google assistant to play message (Homey TTS app), or another option to use regular main powered regular siren and connect zwave relay to it, to trigger it when needed.
@pixel I am currently adding support for this smoke sensor:
https://www.robbshop.nl/z-wave-rook-en-co-melder-met-sirenefunctie-robb-smarrt
Which is battery powered (3x CR123A), but the Siren can also be triggered manually (my ears still hurt from doing this test for your guys)…
Nice thing about this sensor is that it is also possible to link them, where if one of the alarms is triggered (smoke, heat or CO), a english voice prompt will indicate where the alarm is triggered.
WOW! 
The Price of 189 it’s € or RMB? 
All CO sensors (z-wave) are expensive, so not that weird.
Thanks for the answers! I’m aiming towards buying dedicated and powered sirens.
However, as I already have Sonos, is there anyone here with experience about that? Any recommended setup and trigger? Are they reliable? Can you trust them to 99% that they will override any current playlist (so it’s not queued or something like that).
Unless Homey will fail, or your wifi will fail, Sonos should work. I tested it now, and it plays the soundboard sound nicely (changed automatically from TV source and returned back).
