The DFPlayer Mini MP3 Player is a small and low price MP3 module with an simplified output directly to the speaker. The module can be used as a stand alone module with attached battery, speaker and push buttons or used in combination with an ESP8266 via RX/TX.
For more details see this link: https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299
Steps to test this sample: * Connect DFPlayer Mini using RX/TX pins to TX/RX pins respectively of ESP8266. * Copy one or more mp3 file to an SD card. The example playes one file for some time and moves to next one. * Insert that SD card in the slot of the DF Player module. * Flash and run the sample code.