Robotic support for injured joints

Prototype
Strapping on a robotic knee brace at Northeastern University last week, I half expected the device to give me the strength to leap over a workbench or kick a hole in a concrete wall.

But Brian Weinberg, an associate research engineer at Northeastern, was only interested in making me work harder to move my knee.

That is the point of the Active Knee Rehabilitation Orthotic Device (AKROD): It is a sophisticated rehabilitation device with a hinged aluminum frame that can strengthen the muscles around joints affected by stroke or trauma.

I envision a day when the AKROD is just one component in a whole-body workout exoskeleton you'll be able to score at Brookstone. (And you thought you looked silly walking with hand weights.)

You fit the AKROD tightly onto your leg with Velcro straps. The device combines motion sensors with a variable damper mechanism that can provide just the right amount of resistance to prevent hyperextension of the knee, for example.

The AKROD is a fascinating mix of materials science and engineering. The variable damper, connected to mechanical gears in the brace, contains a fluid that thickens when an electrical field is introduced, via a series of metal cylinders.

The AKROD prototype is currently tethered to both a laptop computer (which sets the damp ing level) and a power source. But future versions will be wireless and battery-operated, said Northeastern engineering professor Constantinos Mavroidis.

Northeastern (robots.neu.edu) last week closed a deal with Southwick-based WGI ( wgi.us) to commercialize the knee brace, and a similar device for hand rehabilitation, which I'll tell you about next week.

Prototype

Smart sunglasses let you control the amount of shade

One of my journalism students last semester wore glasses with photochromatic lenses, the kind that lighten indoors and darken in the sun. Of course, she complained they never got dark or light enough, and I could never tell whether she was awake or dozing through my evening classes.

Materials scientists and engineers at the University of Washington have developed a pair of glasses that go from virtually opaque to crystal clear in two seconds. The specs contain a semi-solid gel whose properties change when an adjacent polymer layer is electrically charged.

With UW's "smart sunglasses," you can precisely control the level of shading you want.

The smart sunglasses should appeal to extreme-sports types, "those who love the outdoors," said UW doctoral student Chao Ma.

The UW prototype, a modified pair of lab safety goggles, is not pretty. But UW is working on more flexible, stylish versions, with more lens colors. Right now, the glasses use organic molecules to create a blue tint. Eventually, wearers will be able to shift between several colors on the same pair of sunglasses.

A commercial version of the smart sunglasses could be available within two years, Ma said.

Navigation

GPS navigators can be cumbersome, but LG's device features intuitive controls

I find personal GPS navigators cumbersome and distracting enough suction-cupped to the dashboard. But those devices doubling as media players only makes matters worse. I have an iPod and a car stereo, thank you; I don't need to be futzing with tunes on the thing while doing 60-plus on the highway.

At least LG's Portable Digital Navigators are easier to use than others. The top-of-the-line LN740, for example, has a broad, 4-inch touch screen for interacting with its 2D and 3D road maps. (It comes preloaded with a North American road map).

The LG navigators provide voice turn-by-turn guidance and street announcements, which means you can spend more time with your eyes on the road. Three buttons to the right of the touch screen control the volume and let you surf various menus. The layout is intuitive, and learning to use the device is a matter of simple motor memory.

If you do want to store and play back music and pictures, the devices include wall power adapters, and an SD card slot for added storage.

You can find LG navigators at Circuit City and other stores for $300 to $450.

Innovative Last Week

From Polaroid, a ClickFree photo backup

In a world gone mad for digital photography, and with phones that take megapixel party pictures, it's getting harder to find places to stuff those memories.

Polaroid is selling an attractive "ClickFree" USB hard drive, with a smooth finish, and two simple lights that indicate your connection and download status. The 40GB drive (at shopus.polaroid.com, $139 to $149 ) can store up to 40,000 images, according to the company.

The hard drive, sadly, is not Mac-compatible. But a Mac version should be available by the end of the year, according to Polaroid.