I took a old webcam from a laptop and connected it over usb, it does not work
powerC is input for 3.3V you need to get this from somewhere, you can use a voltage regulator. You can follow the steps in the link which sent by @evildemonic but nowadays thanks to arduino type boards there is a lot of option for tiny voltage regulators, you can check AMS1117 it will work. Just do not give 5V to this pin ever.