USB MP3 Charger replica :)

[zwound]

Ok, so my friend wants to build a charger for his mp3 player. His Mp3 only charges when it's plugged into a computer USB port (which is rated at 500mA and 5V).

so basically, this is how i think it should look, but is it right? The player is rated at 5v, but no current rating, so i think the standard USB amps should be fine?

Here's my little drawing:

 

[petarpav]

Hi. You must use voltage regulator like LM7805, LM2575. MC34064, etc., to make 5V from 9V input, because input current is not constant.

Best Regards.