Measures against insomnia
For those who cannot fall asleep easily

This app uses monaural beat, which is more effective than binaural beats, to induce brain wave and lead to sleep well.

A person's brain waves can be divided into β waves (arousal state), α waves (Relax), θ waves (drowsiness), and δ waves (sleep). With this app, you can go to sleep naturally by guiding the β wave → α wave → θ wave → δ wave gradually. The sound lasts for about 20 minutes.