I paired it with Pimoroni's Pirate Audio headphone out HAT and Geekworm X306
18650 UPS board to give it enough portability. The Pirate Audio application is
very easy to setup on Raspberry Pi OS, so I didn't spend too much time making
it work.
I started with the Raspberry Pi OS lite. After installing Pirate Audio and put
the FLAC/MP3 files in, I turned off swap and set the clock speed to slower at
600Mhz. The Priate Audio software uses Mopidy, so it has a web interface to
manage playlists or skip to the next song, etc. To make good use of it I have
setup a hotspot so that I can connect to the board and access it through the
browser. I have also setup the buttons on the HAT to be play, next, volume up
and down, so that I don't need to always go into the web interface for simple
operations.
Once everything is done, I turned on the read-only Overlay File System option
using raspi-config. Hopefully it will reduce the read-write on the SD card and
extend its lifetime.
Of course it can't be taken outside as a bare board, so I learned how to make
STL files and asked a local shop to 3D-print a case for it. Although in the
end I might have spent quite a bit more than an MP3 player of similar quality
in the market, you know the feel is very different. :)