Instructables
The Raspberry Pi is a wonderful little single board computer that is based on the arm architecture. You can use it for everything from a media streamer, as a server, and all kinds of computer applications. It has one shortcoming at least for now that is a small challenge. It does not use a standard power supply input. You can dissect a walwart and make a special adapter. What I would like to do is to make a generic interface that can be reused if the walwart ever goes bad.

Notice: This instructable requires knowledge of electricity and the ability to solder. We are not responsible  for any and or all issues. Do this at your own risk to any life and or equipment. Get a professional to help even if you are the least bit unsure.Do not solderor touch  anthing while connect5ed to power supply.
 
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Step 1: What is needed:

Picture of What is needed:
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Power adapter via a barrel connector that outputs 5 volts DC with enough current as your Raspberry Pi requires.. (I used the one from my Nslu2 ( 2 amp output) for testing. (Do not use any other boltage (i.e. 12 volts) or you will damage your equipment.
Micro (not mini) usb cable.
Female power plug that will hold the male end of the power supply
We will use the packaging for the female power plug as a temporary case.

Tools:
Wire strippers/cutters
Soldering iron
Solder
Tape.

Step 2: Dissecting.

Picture of Dissecting.
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You will want to separate the usb cable while not connected to anything. Do not discard the non-microusb end as you may need to use it to check which wires are which.

Once you have cut the cable, strip back the main outer covering.

Strip the red and the black wire so they can be soldered to the barrel connector.

If you do not have the standard color coding, you will have to test the cable manually. Be carefully not to touch any bare wires while doing this, as you could be electrocuted. If you are unsure, get a professional to help.
Gelfling610 months ago
When I got my Pi, I assembled a small switchbox, adding a few extras....

a simple SPST switch, simple On/Off..
2 Bananajack binding posts (for drawing +5v for projects)
a $1.00 store USB cable that fits the power socket on the Pi, cut, red & black wires longer, green & white staggered cut so they wouldn't short.
barrel jack & plug that match to the USB hub power supply & hub.
7-port USB hub w/a 3.0A minimum external +5V supply.

Idea being, putting the switch between the jack & the wires to the +5V banana Jack, the center cable of the USB hub plug, and the red USB cable wires. GND to all common (the black USB wire, the black banana jack, the shield of the USB hub plug, and the shield of the jack.) this way, I had all 7 ports available on the USB hub, and I could turn the whole system on & off from the switch box. Now, the fun.. Actually finding time to sit down, and tinker with the Pi.

I'm with amandaghassaei here, this is way over the top. I have many mains USB adapters, and even ones I've bought for £2-3 off ebay are at least 1A. Most people have phone chargers now that are USB adapters >1A, particularly things like iPad.

In fact this is partly (along with cost) why the Pi doesn't come with one out the box - because many people (especially the 'geek' types that will buy this) already have 5V USB.
Computothought (author)  DJAdamDaniel1 year ago
To repeaL "Do not have a wall adapter that supports usb" I used what I had.
why did you choose this route as opposed to plugging your usb cable into a wall adapter?
Computothought (author)  amandaghassaei1 year ago
Do not have a wall adapter that supports usb. Most average wall adapters do not have enough amperage to do the job. Also I have a few 5v ps adapters not being used..