USB in python

[Astan Chee]

Hi,
Im trying to write a program for my USB device and I'm thinking of using 
python to do this. The USB device is of my own making and it is 
activated when one of the two data pins of the USB is given about 5V (or 
similar to whatever the power pin is getting). Now I'm confused to if 
the software to activate this can actually be written and how do I do 
it? Any examples? I've seen pyUSB but it doesn't give me control over 
the hardware and how much power is going through the data pins.
Thanks for any help.
Cheers
Astan