About Sleep Cycle
Sleep Cycle, from the Swedish company Sleep Cycle AB, is a sleep tracking and alarm app for iPhone and Android. You leave your phone by the bed; it uses the microphone (or motion sensor) to estimate sleep, records snoring and sleep-talking, and wakes you during a window you set when it detects lighter sleep. It also has sleep sounds and statistics. A free version includes the basic alarm and tracking; most history, sounds and coaching features need Premium. It is a tracker, not a treatment, and an independent 2020 study that compared it with laboratory sleep testing ('(Not so) Smart sleep tracking through the phone') questioned how reliably phone apps measure sleep.