A small company is now offering a sensor bar for Wii which can run on batteries OR plug into a wall outlet.
The standard Wii sensor bar from Nintendo has many shortcomings. Its effective range may not be good enough for large rooms. The pointer sometimes blinks and skips around when you twist the Remote or turn it upside-down. Most importantly for owners of LCD projectors, the official sensor bar must be plugged into the Wii console. It's not actually sending any information to the system; rather, it's just using the Wii as a power source. It didn't take long for hardware companies to start developing their own sensor bars with separate power sources to cater high-end users with unusual TVs.
Nextronics, LLC is a small electronics company that has been around since 2003, but they have only recently ventured into the video game market. The company has built a sensor bar unusual for its versatility. Not only can you power the device with the included battery pack (which takes AAx3 and is supposed to last up to 36 hours), but there's also an AC adaptor for perpetual power if you prefer not to run through even more batteries than you're already using for Wii Remotes. There's an on/off switch on the battery pack to conserve power after playing, while the AC adaptor doesn't have a switch because it's not necessary.
So how well does the sensor bar perform? I tested it against the official Nintendo sensor bar by pulling up the Wii channel menu and pointing all over the place with a Wii Remote (which had fresh batteries). I tried the same motions and actions with both bars at my normal position on the couch and also as far away as I could stand in my small apartment, and I tested the Nextronics sensor bar with battery and wall power in both of these positions.
From my couch, which is seven feet from the TV, Nintendo's sensor bar works perfectly until I start twisting it. The Nextronics sensor bar works equally well under battery power and, sadly, has the same problems when the Remote is twisted or held upside-down. (This may actually the fault of the pointing algorithm in the system.) With wall power, my couch is actually just at the limit of the Nextronics bar's range, so it works fine at arm length, but the pointer just disappears if I lean back a few inches.
The longer distance test backs up that result. At fifteen feet from the TV, the Nintendo bar and the Nextronics bar (battery power) both start to blink out and have trouble maintaining a signal with the Remote. But with wall power, the Nextronics bar only reaches seven feet before blinking out completely. (Note: IGN's review of this product notes a range of up to 30 feet with battery power, but I could not reproduce those results.)
Considering these results, the ability to plug the Nextronics sensor bar into a wall outlet is basically useless. It's a great idea, but the range is reduced so much that it's not likely to be useful for most setups, especially for anyone with such a large room that a wireless sensor bar is necessary in the first place. Under battery power, the Nextronics bar performs just as well as the Nintendo version, but it's truly wireless and, if the company's claims are true, will last a good long while before the batteries need to be replaced. There are two problems with the battery pack, though. First, you need a small screwdriver to replace the batteries, which is a bit annoying. Second, the attachment cable for the battery pack is only a few inches long, which is going to make it hard to mount the sensor bar above flat-panel TVs, and it's generally just difficult to hide because of this short cable.
You can order this product from the Nextronics online store, and they ship to the U.S., Canada, and the U.K. Try to ignore their website, which could probably qualify for a Something Awful link of the day; the actual hardware is sturdy and looks good. See our hardware profile for comparison photos with the official bar.
Bottom line: the Nextronics sensor bar is a good option if you can't use the official Nintendo device, but don't expect better performance, and don't be swayed by the effectively useless AC adaptor.