They keep an excellent and constant record of everything that goes on, a record that could be incredibly valuable. In government buildings the threat of crime and terrorism is combated with indoor security cameras and other measures. The cameras there are often not discrete they are meant to be seen and taken note of at all times. In both case, having indoor security cameras protecting the employees and visitors have stopped and solved countless actual and would be crimes. Once installed and powered up, you download the relevant app and connect to the device wirelessly. Then, when the alarm goes off, not only do you receive an audio alert—many include helpful voice instructions instead of just a siren—your smart phone also tells you what the problem is whether it’s smoke or CO, which alarm was activated, and sometimes even the severity of the smoke. Many smart smoke detectors hook into additional smart home gear and IFTTT, so you can get even more clever by having the lights start flashing if smoke has been detected, for example. Perhaps the biggest benefit of a smart smoke detector: No more hunting down midnight chirps, since you’ll also get phone based notifications about dying batteries. The Nest Protect is one of the most mature smart smoke alarms on the market, and it’s a no brainer of a choice if you want one of the most sophisticated and reliable smart smoke detectors out there. Alarms are varied, integrated lighting is color coded based on the type of threat, and the product includes helpful voice alerts when activated. In testing, our phone was alerted almost immediately, and the app couldn’t be simpler to master.