one button mp3 / Audio-Player

1.size 28*33*7mm
There is a button in the front,a LED and a 3.5mm earphone connector at one side.
2.control
A short press-another music.(We use random play to make sure every music in the list is played for one time in one Random circulation)
Two short presses-the previous music.(When playing the the first music of a list.It means"The previous List" as well)
3.Power on- any press when the earphonr is connected.
Power off-take out the earphone
4.Automatically volume adjusting
We use a sensor to adjust volume automatically.
Users can set different mathematical model of volume control in Mac or PC.