Industrial MP3 player
This project entailed a creation of a MP3 player on one small PCB with integrated D class amplifier and maximal power output of 20W. The player is powered by 12V voltage, with the audio files being stored on a microSD memory card, the contents of which can be changed with the use of a PC computer or a smartphone. The external switches (from one to three, depending on a firmware version) are used for device control. Potentiometer set up during installation controls volume. Power circuit was optimised for battery operation, which included, among others, the switch-off mechanism for the entire block responsible for decoding and playing.