connect a switch to the usb cable, thats what i did.
Items Need:
-1 <acronym title="Cobb Access Port">AP</acronym> USB Cable
-1 Switch (I went with a slide switch from radio shack)
-Soldering Iron
-Electrical tape
Take your USB Cable, could be the one that came with the <acronym title="Cobb Access Port">AP</acronym> or any USB cable that has the correct ends on it (male normal size, and male mini size).
Strip away a section near the normal side to expose the wires inside.
I stripped away about 2 inches so i had some wire to work with.
You'll see white, red, black, and green and maybe a shield wire.
The wire you want is the black (ground) wire.
Cut it and strip away a bit on each end.
Then get your switch and solder one end to one position and the other to the middle position. So you should have one wire going to 2 of the prongs while the other is left empty. Solder the wires onto the prongs.
Once this is done you can tape things off so the wires don't touch then use some electrical tape and tape the switch to the wire. And thats it.
You might want to try it out on your computer before you tape it all to make sure it works. When the switch is in the far position on the side the wires are soldered the <acronym title="Cobb Access Port">AP</acronym> should be on and when its to the empty position it will be off.
If it works then tape it all up so it looks pretty and install it in your car. Now enjoy that everytime you park or turn your car off you don't have to unplug the cable just flick the switch.