I have had my Nest Protect smoke alarms (battery-powered) for about six years and I’m pleased to say they have never gone off, other than in monthly manual and automatic tests.
I recently installed the HACS integration (using the “cookie method”) and it seems to be working well, but although I can control the configuration switches from a HA dashboard, the actual smoke/CO/heat sensor states never appear to be updated.
I suppose this makes sense if there is no actual fire - even the manual and automatic tests are testing alarms etc. rather than the sensors themselves. I can, of course, test automations etc. by changing the sensor states in Developer Tools. Still, given the critical nature of the device it is a bit concerning.
Is it correct that “last updated” only changes when HA has been restarted? If so, is there any way I can check that the sensors are working - short of lighting a fire in the living room?