ENGINEERING A HOEDOWN

Eric Clapton probably won't lose too much sleep over this news, but some graduate students at the Georgia Tech school of mechanical engineering's mechatronics lab have invented a machine that can play the guitar. Sounds pretty good, too. It's not up to the blistering lead solos in Clapton's “Layla,” but it can strum mean versions of such ditties as The Kinks' “Lola,” “Downtown” by Petula Clark, “The First Noel,” and most any other tune that doesn't require more than the 29 notes it's capable of hitting.

The Crazy J guitar has 23 plastic “fingertips” poised over the first four frets of the guitar's neck, and six independent picks are mounted above its body. The picks and fingers are activated and controlled by solenoids. The Crazy J—which can be heard at www.me.gatech.edu/mechatronics_lab under the “Fall 2000” student projects heading—was one of several projects put on display by the lab earlier this year to showcase the fast-growing field
of mechatronics, which merges mechanical engineering with electronics and microprocessing to control functions.

Charles Ume, lab director, says that products wedding mechanical engineering with electronics have been around for awhile, but the importance of the field has been heightened by the widespread adoption of microcomputers. Other projects by Ume's lab grads include a brewer's aide, which automatically selects and measures the right barley needed for the type of beer to be brewed, and a cash dispenser that doles out specific amounts of money using all denominations of bills and coins.
Clearly some of
the projects have more commercial potential than others. It's doubtful that the Crazy J guitar will ever replace the real thing. But who knows? Some day re- cord producers may decide self-playing guitars are as useful for basic rhythms as drum machines are for keeping a beat and employ them in recording studios. Just gimme some of that sweet solenoid music!

 

SHAKING A LEG

Computer games can be a good way to capture the attention of youngsters and show them how useful technology and engineering can be in real life.

That was certainly the idea behind a computer simulation game created for the University of Kentucky's recent Engineering Day festivities by the school's Center for Biomedical Engineering. Several hundred high-school students who attended were allowed to try the game, which required players, using a mouse, to stimulate the virtual leg muscles of a “person” to move an artificial leg.

The game showcased the growing field of rehabilitation engineering. When people are paralyzed by a spinal cord injury, their limb muscles and nerves remain healthy. Already, paralyzed people can get artificial legs that move by stimulating the muscles electronically. But fine control remains a problem, says Jimmy Abbas, U-K professor of biomedical engineering, because all muscles are different and their responses change as they become fatigued.

The simulation game showed the students just how hard it can be to move one of the limbs. Too little stimulation, and nothing happens; just a bit too much, and the limb can overreact. The Kentucky center is researching a control system to smooth out the differences “and get a more predictable response," Abbas says. (To see how the game works, visit www.engr.uky.edu/eday.) The center has a good track record; among its research successes is the first hip-replacement joint.

Another demonstration that showed how muscular stimulation works also proved popular. Electrodes were placed on the legs of graduate student volunteers, and the high-schoolers were able to make the wired subjects' legs move with the press of a button. Hey, there just may be a commercial product there that would be a hit with many parents.

 

RED LIGHT RUNNERS BEWARE

Drivers who run red lights are a menace, causing about 260,000 accidents and taking about 750 lives every year in the United States. One good way to clamp down on red-light runners is installing video cameras that capture violators on film and record their license plate numbers, so that tickets can be issued. But those cameras are expensive, costing at least $50,000. So when a municipality wants to use them, it helps to know which intersections need the most monitoring.

Enter University of Florida civil engineering professors Scott Washburn and Ken Courage. Along with graduate student Shaun MacKenzie, they're working on a prototype system that combines video and audio equipment with computer software to automatically, accurately, and inexpensively identify those intersections with the highest number of incidents.

The system uses video cameras and audio encoders that can pick up the eight different tones that a traffic signal can emit at a four-way intersection. It also uses detectors at the entrance, exit, and midway point of the crossroads to determine when cars have gone through it after the light is red. The result is an accurate count of the number of cars running red lights.

Washburn estmates that the system could perhaps cost a few thousand dollars, but it would be a one-time-only capital ex-pense. And,of course, the system could be used repeatedly at
different locations. Current ways of determining which intersections have the most violations are neither cheap nor efficient. Some cities post police officers to watch problem corners—but this is not an efficient use of personnel, and it's open to inaccuracies. Intersections can be videoed, but then someone has to spend hours afterward monitoring the tape—another costly and potentially mistake-ridden process.

Near the UF campus in Gainesville, the prototype system has been in place at the intersection of 34th Street and University Avenue. In one two-hour period, it spotted 24 violators in just two of the four approaches. If that sounds hair-raising, consider that Washburn says there are other intersections in the city where the problem is almost certainly worse.

In addition to helping law-enforcement agencies, Washburn says they hope the equipment can be used to help study the behavior of drivers who run red lights. That could help in developing engineering and design techniques that might make dangerous cross-roads a bit less lethal.

 

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