As an alternative to smart smoke detectors like the second-gen Nest Protect, the Kidde RemoteLync Monitor plugs into your wall and listens for smoke and carbon monoxide detectors. When the alarm sounds, it'll hear it and send you a push notification.
The light on the top will shine yellow as you test. Press the button on the left to sync the device with Wi-Fi. Further along in the setup process, you'll press the button on the right, then sound the smoke detector furthest from your alarm.