Starting today, Apple HomePod smart speakers can alert you if a smoke or CO detector goes off in your home. The Sound Recognition feature, first announced when the second-gen HomePod was launched earlier this year, listens for the alarm sound and sends a notification to your phone. Apple says the capability is now rolling out on the first- and second-gen HomePods and the HomePod Mini, though we haven’t yet seen it in our apps.

For this to work, you’d need to have smoke and CO alarms installed in your home; the speakers cannot detect actual smoke or carbon monoxide. But they don’t need to be smart smoke alarms or have any internet connection, which is good news. Currently, the only smart smoke alarms compatible with Apple Home in the US are First Alert’s Onelink, which start at $170 each, so this will be an attractive new feature for Apple Home users.

When the speaker hears the unique signature of an alarm, it will send a notification directly to your iPhone Lock Screen (and your Apple Watch or iPad). Tapping on the notification lets you “drop in” on the HomePod from an iPhone or iPad to hear what it's hearing. Siri will then announce on the HomePod that someone is checking in. Apple showed me a demo of this earlier this year when we reviewed the new HomePod.

If you have a HomeKit-compatible camera in the same area, you’ll also get a live video feed of the event in the notification. All audio analysis of the alarm sounds happens on-device, and if you check in through the HomePod remotely, the feed is end-to-end encrypted.

Amazon’s Echo smart speakers have been able to listen for alarms for a while now through the free tier of its Guard feature. But they don’t have the same direct integrations with cameras in your home (although if you have an Echo smart display, you can check in using its built-in camera). Google’s Nest smart speakers can also listen for alarms, but you have to pay for a Nest Aware subscription for the feature. Several smart security systems have smoke alarm listeners that have a similar function. Ring’s $35 Smoke Alarm Listener, for example, can do this. But that requires a Ring Alarm and a monthly subscription.

Google’s Nest Protect smart smoke and CO alarms can connect to any Nest cameras in your home to send you a snapshot of whatever is happening in your home when an alarm goes off, even without a Nest Aware plan. But this only works with Nest cameras and the $120 Nest Protects.

To enable the new Sound Detection feature on your Apple HomePods, you need to have the new Home architecture enabled, according to Apple’s news release. This returned with iOS 16.4 last month after Apple released it and then pulled it last year. Sound Detection does require some setup in the Home app, but we’re not seeing the option in our apps yet.

Updated Tuesday, April 18, 2:40 PM: Added that the Sound Detection feature is also coming to the first-gen HomePod.