Finally: Smartphones improve smoke detectors.
Smoke alarms, which have become a standard and required feature of every house and apartment, suck: http://goo.gl/4Zex17
They typically emit a high-pitched tone when activated, and it's difficult to tell which direction the tone is coming from. When there’s a fire, knowing where that fire is happening is the most important fact. Also, children and some adults have slept through smoke detectors in tests.
Many people have trouble controlling their alarms, which go off each time they cook or for reasons unknown. So they remove the battery and leave themselves unprotected. Most smoke detectors run on just one battery, which has to be changed frequently. When the battery is low, most smoke detectors sound off with a loud beep, which can happen in the middle of the night and scare everybody. You often need a ladder to reach them to turn them off.
Finally, a new breed of smoke and carbon monoxide detector is coming on the market. How cool are these?: http://www.houzz.com/ideabooks/18904041 #smokedetector