Apple approved: Lark is an app and armband that track, score, and offer advice on your sleep patterns. The $99 system, sold in Apple stores, was designed with advice from sleep researcher Jo Solet of Harvard University. The armband contains accelerometers that transmit your movements to the app. Lark also acts as an “un-alarm,” vibrating to wake you at a point in your sleep cycle when you will feel alert, not groggy. 

Credit: Lark