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?
Go to your local hardware store or Amazon and get a can of smoke alarm test spray.
Its specially formulated to mimic what should be detected as smoke but not cause odor or damage and not load up the detection media.
Use it sparingly smoke alarm detection media has a limited life and is designed to last approximately 8-10 years in normal operation (read: don’t go nuts testing you can actually wear the detector out)
Most people don’t. But it’s the most reliable while least destructive test. If I remember right they’re usually safe enough to use on a monthly or quarterly cadence without hurting anything. A couple extra squirt while you get your automation dialed in shouldn’t significantly hurt lifetime on those either. Its what I use on mine (5 year old Protects)