EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Krowez on March 18, 2016, 01:00:33 am
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I have been playing with my raspberry Pi 2 ( more than a xmbc media center that is ) as of late since the release of the Pi 3.
I have found that my usb external hard drive that I use with it has drawn the pi to a near stop due to it's power draw from the bus.
I have remedied this with a powered hub but was thinking since I have a half dozen cables & power adapters lying about that i might be able to skip the hub all together and just power the drive from that rather than pulling from the Pi.
My Plan is to take the primary USB cable and cut the reb and black wires so it doesn't provide power from the pi's USB bus.
Then take the second cable and connect red to red and black to black and have it powered from a usb wall adapter that has the proper power support.
Is there anything that might cause problems as the pi's bus not being able to acknowledge that hard drive's existence without the power connected ?
I have done some similar off the cuff things before and have ruined other projects in the past.
thanks for your input in advance.
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Cut the red, leave the black.
I am confused with that statement.
I understand the cut the red part, but should I splice in the black cable from the new power cable ?
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You should splice the black as you've stated.
The raspberry pi needs to be ground referenced to the hard drive... The wall adaptor should be isolated if it is a reputable manufacturer which breaks any ground loop. USB has a somewhat limited common mode range even though it's differential signalling.
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the power adapter i have is a cheap brand but honestly provides the full 5v 1a that is says it does.
but thanks for the input i shall put this to the test here shortly.