说明：  基于AVR 的 MP3 播放器源代码，无按键设计。
(this is the third MP3 player project in succession. In this project, I designed it as a simple and small audio player compared to previous large scale graphic MP3 player project and implemented an additional strange gimmick. The MP3 player does not have any buttons nor dials that shown in right photo and it has an acceleration sensor instead of the mechanical switches. Therefore all playback commands to the player are given in defined motions, such as inclination, tilt and shock. The player detects the motion with the built-in acceleration sensor and recognize it as a playback control command. As the result, it came to not seem an audio player in appearance.)