When Nintendo unveiled its Wii console, it also showcased a prototype sensor bar - a device that system owners already know all too well. Early on, it was believed that the sensor bar not only generated a field that miraculously interacted with the controller, but that it also transmitted motion data from the Wii remote back to the console itself. As it turns out, we all gave the sensor bar way too much credit. In fact, now that we have a better understanding of the gadget's job, we also know that Nintendo's little bar is expendable - it doesn't do what you think it does and you may not even need it. Would you believe that you could replace it altogether with a couple of household items?
Nintendo's sensor does serve an important purpose. The bar itself is really nothing more than a shell for two infrared sources - one on each end. It's the same technology commonly found in a variety of electronic devices such as television remotes. The infrared sources located in the sensor bar emit lights that can't be seen by the naked eye, but are nevertheless plainly visible by the Wii remote, whose tip features a very basic camera that can read IR data. The Wii remote uses the IR sources as a calibration point, setting the left and right boundaries. It's very simple tech, but it works. The Wii remote doesn't see your television when you point at it - it sees the IR sources on the sensor bar and orients itself based on those points.
Think of the sensor bar as your controller's beacon. If the Wii remote is a ship, the sensor bar is the lighthouse. And if the Wii remote is an airplane then the sensor bar is the illuminated landing strip. We're running out of analogies so we hope you've latched onto the concept.
Wii Can do Better.
The Wii remote's accelerometer-based motion control works with or without the sensor bar. You can play games like Tony Hawk's Downhill Jam and you won't need a sensor bar to do it. But for titles like Red Steel or for procedures like aiming the bow in Zelda, well, that's sensor bar territory.
There are a couple of problems with the sensor bar, though. The first is that it's wired, which has presented some hurdles for gamers with sprawling entertainment centers. Although the wire stretches for approximately 10 feet, that length is still not enough for some living rooms, and hence players have been forced to reorganize their setups entirely in order to accommodate the system. Take, for instance, our demo room. In order to stretch the sensor bar to the front of the space, we've had to put our Wii in the center of the room with wires running in both directions, which is hardly ideal.
The second, arguably more troublesome shortcoming lies with the power of the sensor bar. The two infrared sources it emits match the power of two flames from a lighter, and the Wii remote is unable to accurately track the spots from a distance beyond nine feet. Again, if you've got a larger living room, you may have already noticed the jittery, jumping movement of your Wii-mote reticule when you're stationed more than nine feet away from the console. If your sensor bar is at a raised angle, the distance may actually decrease. Obviously, there are quite a few consumers who sit 10 or even 15 feet away from their television and as a result these people have encountered the issues we reference.
If you fall into either of the above categories, we have good news for you. You don't really need the sensor bar. It doesn't transmit any data to your Wii console. That long, thin wire - it only plugs into Wii for power. And as it turns out, if you're crafty and imaginative, you don't even need it. You can buy IR sources at your local Radio Shack and create your own makeshift sensor bar. Or, you can alternatively set two candles on your mantle, light them, and have fun. No, really. The flames on the candles output a similar IR imprint that the Wii remote can read. We know because we recently tested whether or not using lit candles as a replacement for the sensor bar was a viable alternative and after extensive play, we can state that they perform very well. In fact, in our tests two lit candles - spaced about a foot apart - offer nearly the same accuracy and range as the sensor bar itself. Larger IR sources, such as bigger flashlights, will get your even more accuracy and range.
If you'd rather not make due with a homemade solution, though, you won't have to wait long for something more official. Now that the cat is out of the bag, third party hardware makers will soon have what for many is the sensor bar equivalent of the holy grail: a wireless, battery-powered device that emits larger IR fields than Nintendo's bar.