Make sure your device audio is turned on before use (not in vibrate mode)!
This frequency generator allows you to generate sine, square, sawtooth, or triangle waves in the 50HZ to 16000 HZ range. The app is easy to use. It can probably be used for multiple purposes, such as dog whistle, noise maker, tinnitus relief, relaxation or meditation, or just annoying your friends.
You can set a custom frequency, set a timer, or even tune to a musical note.
Let me know what extra features you would like to see added!