Note: This device is not intended for people with hearing problems it lacks a flashing strobe of light and the 85db alarm may not be enough in such cases. The Nest Protect runs self tests regularly every 200 seconds to see the status of the batteries and sensors and you can also run a full test to check at any time during this process, you’ll notice a blue light rotating around the button. If you have more than one Nest Protect detectors, you can interconnect them wirelessly the device supports the 802. 11b/g/n standard and Bluetooth Low Energy technology and, in case of an emergency, all the devices will speak at once telling you the location of the triggered alarm the devices shouldn’t be more than 50 feet apart from each other. The wired and battery models can be connected wirelessly up to 18 and you can also connect the Nest Protect with other Nest smart products such as the Nest Learning thermostat. Now, let’s talk about the elephant in the room or the Nest!: the security and privacy of your data. As you know, Nest is owned by Google, so this already makes people more cautious about their privacy. There has been a reported backdoor more than a couple of years ago on the Nest thermostat, but the Nest Protect was and remains unaffected by the IoT vulnerabilities and there are many. Now, Nest admits on collecting data from your system to analyse the average battery life, it records data about any adjustments you make to the product and the history of all changes, but it insists that all collected data is not sold to third party companies and the info may be shared but not before the user gives explicit permission to do so. The First Alert Onelink Safe and Sound is the newest smoke and Carbon Monoxide detector from the US based manufacturer and it is the second attempt at creating a worthy competitor to the widely popular Nest Protect 2nd Generation. I purposely skipped the first generation of OneLink because it was a mess software wise the app was unstable and the device would constantly trigger false alarms, so the company has worked hard to fix these issues and hoped that this new device would receive more positive feedback from the audience.