DFPlayer Mini MP3 audio module. Very interesting for generating sound from an onboard microSD card and an Arduino board a mp3 player based on a DSP and a 3W mono audio amp.
With Arduino the default cabling is as follows. Connect the Rx pin of the audio module to pin 11 of the Arduino board (software serial link to send commands such as playing an audio file stored on the micro SD card by giving the file number). Connect the Busy pin of the audio module to pin 12 of the Arduino board to possibly wait for the end of the current playback.
The mp3 files should be saved on the micro SD card in a folder at the root named "mp3". The name of each mp3 file must start with a number: 0001 Example1.mp3 0002 Example2.mp3 No emphasis in the name of the files.
Link for the download of the library to install imperatively in the Arduino software: