SD Card MP3 Player as SD Card Only?

Asking hypothetically, could the SD Card MP3 players you find on eBay for a few bucks...

be utilized for just for SD read/write? Is there a difference between a SD specific shield or module and these players where you could not read/write?

Thanks for the input.

I don't see a 5V to 3.3V regulator there. SD cards typically draw more current than the 150mA the 3.3V regulator on an Uno can supply.

The model shown (and the one I have) in the picture is identical to the DFPlayer Mini

which is 5V VCC

The library that comes with it allows for simple variables to READ from the SD card so I was wondering if the build of it would not allow for using it as simply as a SD shield

If you check the commands possible, I'm afraid... you can't read or change the contents of an SD-card using this module + Arduino.

Most commands are used to pick the right song and start it, others give you the possibility to change volume etc. You can apparently also query some... features.

But none of the commands actually give you the possibility to read the name of a folder, read x bytes of a file or create/append one.

I guess the player is just a player, if you want to change a file on SD you probably need to do it with a computer.