INCLUSIVE. THIS DEVICE IS CALLED A BED SHAKER, AND IT’S DESIGNED TO WAKE YOU UP IN CASE OF A FIRE BY DOING EXACTLY WHAT IT SOUNDS LIKE. SHAKING YOUR BED. FIRE. WAKE UP. THIS ISN’T A GENTLE MASSAGER ...

Your smoke alarm’s chirp can be oddly reassuring, a small sound that suggests everything is still working. Yet the device making that noise may already be too old to reliably sense a real fire. The ...