This is a rather simple guide, but no photos right now.
2. A lighter (key item)
3. Speaker Wire
4. Tape or something to cover up the wire once you have spliced it.
Step one: Cut the sensor bar cable wherever you would like to splice in additional wire.
Step two: Strip enough of the wire so you have access for splicing.
Step three: With the lighter, carefully burn the coating off the wire so you are able to splice it. The wire is enameled, so without doing this step the cable will not work at all.
Step four: Splice the speaker wire with the sensor bar cable.
Step five: Set up your sensor bar with its now extended cable at the base or top of your projector screen, and off you go.
For those of you who do not feel comfortable doing this with your one and only sensor bar you can pick up another one from the Nintendo shop for just $10.