* volume key is not supported. (Specification) It developed for the purpose of something remote control, You can use media button of bluetooth receiver (such as Sony DRC-BTN40). Working in the background, you can use it even when the screen is off. What the app can do is just broadcast the Intent when pressed on the media button. Since the content of Intent needs to be set by the user self, in order to use Knowledge of Android application programmer may be necessary. (Merit) Using the media