I have a bunch of aqara sensors on doors and windows and using Z2M with google speakers, while this has worked just fine as a security system, my biggest concern is that with HA there are multiple points of failure.
Host server has a hardware failure while away.
HA VM crashes (only happened once) while away.
Network goes down i.e. router failure.
Z2M crashes or SD card failure on Pi.
Internet goes down, google speakers are useless. I haven’t found a cheap alternative for a local speaker that I don’t have to DIY.
I wanted to make sure that when any of the above occurs the security system remains operational and is not dependent on a network or HA. Enter the M1S, this allows at the very minimum for the alarm to go off if everything else has failed, sure I may not get notifications but that’s the worst-case scenario until I can add a backup internet connection. I can still make use of the HA security system and still play sounds on the google speaker if I want too so no functionality is lost.
The M1S integrates well with HA using HomeKit and still allows for automations with the sensors, exposes the security system and ring light, so you don’t need to use the aqara app at all after initial setup.
M1S Pros:
Full HA compatibility with HomeKit
Fully functional offline with HA if there is no power outage **see con
Fully independent of other devices
Alarm returns to last state after power outage even if the internet does not come back, meaning if you set the alarm to AWAY the alarm stays on AWAY after a power outage.
M1S Cons:
Alarm setup must be done in the Aqara app, but as noted it does not rely on the internet for functionality.
HomeKit does not expose the speaker or sounds.
**If there is a power outage and the internet does not come back after power is restored, M1S goes into a limbo state, the light continues to blink blue and cannot be changed but the alarm does still function. This means for small internet outages or power loss the M1S does not become useless, but the hub should not be blocked from the internet 24/7/365. I guess you can plug it into a UPS so it doesn’t go into the limbo state at all and then you can block it from the internet.