I have a model B raspberry pi and an external hard drive that requires more power than the usb port on the raspberry pi can provide. Is there any way to increase the power to the usb port so that I can connect the hard drive to the raspberry pi without using a powered usb hub?
If you are willing to modify an existing USB cable, you can remove the +5V line from the Pi and add your own +5V power supply to the line. Research the pinouts before you get started. A good discussion of doing something like this is on Head-Fi.
There are a few important notes though that need to be highlighted before trying this:
- Your external power supply, the Raspberry Pi, and the USB device must share a common ground. If using standalone power supplies, they should be on the same circuit.
- USB devices expect +5V +/-0.2V. If you are on batteries, what is your expected behavior when the batteries are dying. If you bring your own power supply, have you tested it for conformance both without and with a load?
- The USB device may not tolerate line noise, so be aware of your power supply type and what kind of filtering comes with it. An existing USB power supply, like those needed for the Pi, are probably your best bet.
- Do not let your external power supply connect to the host +5V pin since the behavior on the Pi probably involves letting the smoke out of the wires.
- I would think twice before using a Y-splitter in combination with an external power supply, since you will be violating the line on the previous bullet.