Hack20.Make a USB-Powered Charger

Hack 20. Make a USB-Powered Charger

The PSP ships with the usual bulky charger, needing to be plugged into the walls to get its juice. With a simple mod, you can make your own USB charger and charge the PSP with your computer.

To build your USB charger, you'll need everything shown in Figure 2-58. In addition to your PSP, you'll need a USB/USB mini cable and a 5V charger (I used one from an old CD player). Wire cutters and electrical tape will also be a big help.

Figure 2-58. The ingredients for this hack

I usually keep a box full of old gear, power chargers, and especially USB cables; they always come in handy for projects like this.

To get started, chop the USB cable in half, spreading and stripping all the wires. You should have four wires: red, black, white, and green.

Some USB cables may have different colored wire, in which case, a little trial and error may be required. I use a voltmeter to determine which wires carry power and to determine their polarity (+ or). This eliminates the other two wires (data, which we don't care about for this hack). Here's what your wires probably look like:

• USB Ground is the black wire.

• USB +5V power is the red wire.

• USB Data + is the green wire.

• USB Datais the white wire.

Twist the white, green, and black wires together as shown in Figure 2-59.

Figure 2-59. Connecting the USB wires

Make sure the power cable is unplugged, and chop the tip off the 5V power cable to expose the wires, as shown in Figure 2-60. The wire with the white writing or lettering usually is positive (+), but examine the power charger you are cannibalizing or use a continuity test to verify that the center of the charger is positive (there's a small diagram on the PSP itself showing the polarity of the power plug; check this to be sure you know where the positive should go).

Twist the red wire on the USB cable to the positive on the power cable, and the remaining bundle of wires to the ground, as shown in Figure 2-61.

Plug the USB cable into your computer, then test the voltage with a voltmeter on the exposed wires, as shown in Figure 2-62.

Figure 2-60. The power cable with exposed wires

Figure 2-61. Connecting the USB and power cables

Make sure you're only getting 5V or a little less, but never more. If you're not, double-check the wiring. You can pick up a voltmeter at just about any RadioShack or electronics store, or even on eBay for under $20 USD or so.

Use electrical tape to protect the wiring [Hack #15], wrapping the tape around the positive and negative wires separately or soldering the wires together.

That's itthrow this cable in your bag and you'll never need to look for an outlet again, as long as you have a USB port handy!

2.10.1. Hacking the Hack

Wouldn't you rather have a single cable that functions as both a data cable and a USB power cable?

Get a USB to USB mini cable that you'd normally use for data transfer and chop it in half. One is included with the PSP, or you can usually find one for a couple bucks.

Strip the wires on both sides of the chop, as shown in Figure 2-63.

Figure 2-62. Testing the output

Figure 2-63. Stripping the cables

Wire them together, as shown in Figure 2-64. Use the 5V tip from the USB power cable hack and wire the positive red (+) to the red wires of the USB data cable. Wire the black () to the black wires on the USB cable.

Figure 2-64. Connecting data to data and power to power

Plug the cable into a computer and test the voltage; it's important that the polarity be correct. If in doubt, compare to the diagram on the PSP's power plug to determine where positive and negative should be delivered.

That's it! You now have a dual cable! You can either solder it up or make a small enclosure to house it all.

Phillip Torrone