Nest Protect Wired Smoke and Carbon Monoxide Detector Nest has a number of helpful home devices, from indoor security cameras to WiFi programmable thermostats, but we think this Protect Wired Smoke and Carbon Monoxide Detector ($119) is a necessity. Simply connect to your phone and you can see if there is smoke or a carbon monoxide leak even when you're not home. Image Source: homedepot.com Protect Wired Smoke and Carbon Monoxide Detector $119 from homedepot.com Buy Now