The Smoke Detector
Nest took its design ethics and tackled the smoke detector, a device fraught with false alarms, low-battery chirps and safety issues since many take out the batteries just to get the darn thing to shut up. Nest Protect, which is a smoke and carbon-monoxide detector, tells you audibly or on a smartphone what room the smoke is in and, if the smoke doesn't dissipate, sets off the alarm. If it's just smoke from cooking, you can wave a hand past it to hush it up. Smartphone notifications will let you know when a battery runs low and, most importantly, which detector needs changing.