USB Specs

[DiamondFire13]

I am making my own LED lighting system, and I am wondering what the USB spec is so that I can draw power from a USB cable. I just want really dim light from a white LED. It will be pretty easy, I was just wondering what pins are power etc and if there is a signal that I need to establish to make the port active or if a voltage differential is always established between two of the pins.

Thanks

 

[neuralfx]

http://www.usb.org/
i think they have whitpapers and all that jazz there.. have phun..
-neural

 

[DiamondFire13]

yeah, after looking through 300 pages of specs, I fouind it!!!

Thanks

 

[EricHagen]

You can definately draw power off the lines- they're designed for that.

You can run small devices like cameras off those power lines. Go to firewire if you need a higher current draw. It can even handle small harddrives. =-)

Eric