TinyPlayer is an IR remote controlled and LiPo battery powered MP3 player based on ATtiny13A and DFPlayerMini module. The DFPlayer module is controlled via a simple cycle-precise software implementation of the UART protocol (8N1, 9600 BAUD) in half-duplex mode. The volume last set as well as the track number last played are saved in the EEPROM and automatically loaded the next time it is started. TinyPlayer has a built-in battery charging circuit, which is supplied with power via a USB-C connector. You can directly connect a 3.7V LiPo battery and a 3W/4Ohm speaker to the board.