but if an led shorts, won't the usb port turn off automatically?
can i build in a safety thing somehow? maybe a zener?
and how can i measure where the 5v are coming from? why doesn't it work if i just measure between black and red cable?
this is the cable, im pretty sure the red cable supplys 5v and the black one is GND (i already cut the green and white ones because and - i didnt really know what i did - i measured ampere too. putting the amperemeter between red and black one, the usb port immediately shut down and mac os said it was drawing too much power):
