USB mp3 player with some type of communication

Hy,
I`m here again after a loooong time of doing some other stuff (mostly microcontrollers) and I`m so glad that I know there are alot of audio experts here.

My goal is to integrate USB mp3 player in BMW e39 Bussines (Becker 3350) radio.

I went thru some hard headaches in last four weeks to gain control over multifunction steering wheel buttons and to control original dot matrix display that is on the radio.

To find out one thing: that I can`t find suitable device that would play music mp3 files of USB flash drive and output filename of the playing song over uart, i2c, ttl.... 5v logic....

It would also be nice if I could control play/pause, prev/next with same interface, but it`s not necessary - I can hardwire buttons if no other option...

It would be a nice thing if that device would continue playing on last song played before shutdown, but again I can work around that (leave it on, command it to pause when I turn the radio off).

LIMITATIONS:
1.) Power source - as it will be used in the car... 12vdc max, could step up, but that would introduce unwanted noises fast, I believe such devices use lower voltage (5v, 3.3v, etc) anyway.

2.) Size - would prefer smaller size, as I would like to put everything inside the radio, where tape player was, but DIY friendly if possible.

3.) Datasheet availability for the IC would be fantastic as spending time to capture data and converting that into understandable values is not the most fun thing to do.

4.) Price -I`m not aiming for state of the art studio quality system, just something you can listen to in the car. The cheaper the better.


Finally you may ask:
Why I don`t go for android headunit?
-I would like to keep this car original, I like how it looks when it all comes together. If it was any other car... ok, but this car... I`m just in love with everything about this car, including the design.

Why don`t I use already made, ready to buy CD changer simulator?
-It`s available, but sadly my radio would not display song names with it... just Track 1, Track 2, ...
If I would want to retrofit better OEM radio that would display filenames such as MID or SAT NAV it would cost me up to the 1500EUR... yes these second hand units are still expensive.


I hope that you can help me, I spent a lot of effort to get the steering wheel buttons and display working with arduino and now I`m stuck.

So if you have any possible solution please shine some light on me.
 
Use a Bluetooth dongle on USB port...
Do not over complicate things.
Becker 3350 on BMW is German, those designers know little of electronics, and are kludgy, simple stuff is easy.
And apps are easy to upgrade, so are phones...


Or use a USB tethering cord from phone, that would make it wired to the radio.
 
Last edited: