One of the coolest apps for the iPhone 3G was a sleep tracker. You ran the app, placed your phone on your bed while you slept, and it used the phone’s novel accelerometer to track how much you tossed and turned. It was a bit awkward to use – your phone had to be charging all night, the screen needed to be on and facing down – but the sleep graphs it produced were awesome looking (and occasionally informative). Seven years later, and Samsung are releasing the final form of sleep tracking: a sleep sensor that rests in your bed permanently, tracking your sleep patterns and delivering the results to your smartphone without requiring you to keep your phone in bed or a wearable on your person. This is Samsung SleepSense.