Sleep Metronome is a sleeping aid that uses the sound of a metronome to help you fall asleep.
By starting the metronome at a rate close to your own heart rate, and then setting the beats to slowly decrease over time, it will help you to relax and fall asleep. Focusing on the sound of the metronome will reduce other distracting thoughts that can crowd the mind. As the metronome sound slows, your breathing will slow along with it, thereby helping you to relax.