The Somfy smoke detectors on this page warn you of smoke development in your home. You'll hear a loud alarm, and you'll get a notification via the Somfy app. If you link multiple Somfy smoke detectors with each other, all smoke detectors in your home go off at the first signs of a fire. You do need a Tahoma switch for that, which allows you to connect your detectors to all your other Somfy devices right away. This way, you can watch the camera feed of your Somfy One when there's a fire.