If you have a bunch of device-specific 5v power bricks and some USB Type-A extension cables lying about...

...You should join the two together, and turn all your power supplies into universal USB power supplies. Here's How:

FOLLOW THIS PROCEDURE AT YOUR OWN RISK!!! I AM NOT RESPONSIBLE FOR ANY DAMAGE CAUSED BY FOLLOWING THIS GUIDE!!

You will need the following parts:

• A 5 Volt Power brick (must be at least 0.5A/500mA and EXACTLY 5v DC)
• A USB Type-A Extension Cable
• Some Heatshrink tube (or electrical tape if your cheap and want to do a dodgy job)
• Solder

Tools:

• Soldering Iron
• Side Cutters
• Some heat source for the Heatshrink tube (I use a regular Bic lighter for quick jobs like this)
• A Multimeter (not necessary, but highly recommended. A single LED can be used as a simple continunity tester in this case)

Method:

1. Check that you have the right values on the power brick. Picture

2. Cut off the end of the power supply & cut the USB extension cable in half. Picture 1. Picture 2.

3. Take about 1" off the outer sheath on both exposed ends. Picture 1. Picture 2.

4. There should be only 4 wires coming out the exposed end of the USB cable, you only need Red & Black, so cut the other two off (There is probably going to a braided wire sheath encasing the wires, cut this off too). Slide down about 1-1.5" of heatshrink tubing. Picture.

• If they aren't using the standard colouring of Red(+5V), Black(GND), Green(D+), White(D-) then you will need to get a volt meter/continuity tester and find the +5V -- If the cable has a wire braid around the wires, use that for ground while testing.

5. Strip a small amount of sheath off the Red/Black wires for both the power brick, and the extension. Picture.

6. Tin up the exposed copper wire then slide small pieces of heatshrink tubing down each wire. Picture.

7. Solder the Red wires together, repeat with the Black wires. Slide the heatshrink tubing over the exposed soldered wires then use brief bursts of heat over the tube to shrink them. Picture 1. Picture 2.

8. Finally, slide the larger bit of heatshrink tubing over the two wires and shrink that too.

Finished!

It is a very good idea to test it to make sure its not shorting, in reverse-polarity or going to send a killer voltage down your equipment. I stripped the wires on the other half of the USB cable and bought a multimeter to the Red/Black wires (well, Red/Brown in this case):

• Picture. This one is reading a stable 5.07v which is well within the tolerance allowed.

Do not use:

• If it is showing a voltage outside of 5V+/-5%.
• If it is showing a negative voltage on the multimeter (this means the polarity is reversed or its pushing out a negative-biased voltage -- reversal of the red/black wires should fix this)
• If the power supply starts smoking, making cracking noises, trips the fuses to your house, the joints/wires are melting/burning or if your house is in flames due to not removing the power supply from electricity after experiencing the previous effects.

Ok, so what about the power supply I just destroyed? I still need to use it for what its originally designed to power.

• Easy. Just follow the same procedure on the two cut off ends. Before. After.

Now your device can be powered from any USB port, and you can use its power brick to charge any USB device.

FOLLOW THIS PROCEDURE AT YOUR OWN RISK!!! I AM NOT RESPONSIBLE FOR ANY DAMAGE CAUSED BY FOLLOWING THIS GUIDE!!