04/03/2000 Design News

ENGINEERING NEWS

Sensors help drivers stay awake

Plymouth, MI-A car that prevents drivers from falling asleep at the wheel is much closer to becoming a reality thanks to designers at Johnson Controls. "The technology is here. We just need to learn more about sleep patterns," says Bob Munson, the manager of product planning and business development at the company.

Johnson Controls equipped a 2000 Lincoln LS with a Driver Drowsiness Alert System. "We're looking at different ways of monitoring the onset of sleep," says Munson. "One way involves the use of cameras that watch the eyes of the driver. Another involves monitoring head nods," he says.

The Lincoln uses vehicle-mounted capacitance sensors and a microprocessor for monitoring driver behavior. The capacitance sensors mount in the vehicle headliners. The system can deliver a variety of warning signals if the driver begins falling asleep.

"We are working with a sleep lab in Massachusetts," says John Eaton, the market segment manager for luxury cars at Johnson Controls. "We are probably a year or two away from nailing this system down," he says.

-Bruce Wiebusch, Regional Editor

EV1 unplugged

Detroit-In a setback to use of so-called zero-emission vehicles, early March found General Motors recalling its 1997 Generation I EV1 electric cars and 1997-98 S-10 Electric Trucks. The company says the vehicles were produced with a charge port that may fail during charging. If this occurs, heat could build up within the port and a fire result. GM's advanced technology group says that although the small part can be replaced in the pickups, the more complex EV1 installation precludes repair. The notice said the company would assist in termination of the lease, and "discuss your immediate transportation needs." Generation II, 1999 EV1s were not involved "due to their uniquely different charge-port design." The company says electric vehicles are still very important to GM.

Pneumatics pump up drone

Easton, MD-BAI Aerosystems Dragon Drone unmanned aerial vehicle (UAV) provides land and sea forces with an ability to do reconnaissance, at a range of 50 miles for missions up to three hours. An effective launch system and recovery skids or shipboard net permitted its designers to cut vehicle weight by eliminating the landing gear.

But when shipboard launching was needed, difficulty with the existing launcher became apparent, according to Jay Willmott, vice president of BAI Aerospace. Previous launch methods flung not only the UAV out off the launcher, but its cradle as well. Aboard ship, such discarding of components overboard was not acceptable.

BAI engineers redesigned their launcher that retains the cradle around a pair of rodless pneumatic cylinders from Hoerbiger-Origa (Glendale Heights, IL). These 80 mm (3.1 inch) bore devices have a 3m (9.8 ft) stroke and accelerate the 50 kg (110 lbs) drone to 100 kph (62 mph) during launch. The cylinders are first charged to about 8 bar pressure with bottled nitrogen or air from a compressor. According to Hoerbiger-Origa Mechanical Applications Engineer Stephan Barry, once launched, shock absorbers in the cylinder end caps and specially machined holes in the cylinder barrel decelerate the cylinder pistons along with the UAV's cradle. The shocks directly absorb energy, while the holes bleed pressure once the pistons pass them.

Willmott says, "Reliability has been excellent, even in desert environments."

The rodless pneumatic cylinders allow rapid, successive drone launchings.

-Rick DeMeis, Senior Editor

`Quantum mirage' makes nano-circuits possible

San Jose, CA-Physicists at IBM's Almaden Research Center have demonstrated a working circuit as small as an atom-that's one-tenth of a nanometer wide-which does not use conventional wiring. The breakthrough promises to radically change modern electronics, making for new circuits with a thousand times the storage capacity of today's chips.

The atomic-sized circuit employs the wave nature of electrons to transfer data through a solid in place of wires in a"quantum mirage effect." "We call it a mirage because we project information about one atom to another spot where there is no atom," said Donald M. Eigler, lead project researcher.

As computer circuits shrink to the atomic level, the behavior of electrons changes from being particle-like to wave-like. On such small scales, tiny wires don't conduct electrons as well as classical physics predicts. So quantum analogs must be available if nanocircuits are to achieve the performance advantages from their small size.

To create the quantum mirage, scientists moved several dozen cobalt atoms on a copper surface into an elliptical shaped ring-"quantum corral"-reflecting the copper's surface electrons within the ring into a wave pattern predicted by quantum mechanics.

The size and shape of the elliptical corral determine its quantum states-the energy and spatial distribution of the confined electrons. The IBM researchers used a quantum state that concentrated large electron densities at each focus point of the elliptical corral. When the scientists placed an atom of magnetic cobalt at one focus, a mirage appeared at the other focus: the same electronic states in the surface electrons surrounding the cobalt atom were detected even though no magnetic atom was actually there. The intensity of the mirage is about one-third of the intensity around the cobalt atom.

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HDTV pushes displays to perform

Plano, TX-Does Monday Night Football have you eyeing your 27-incher and wishing for a high-resolution big screen to make those images look like a seat on the 50-yard line? If you're like many people, you may be holding out on that big screen purchase. Poor picture quality in today's systems may be the reason why. Another downside is size-you may think you have to give up the whole living room to get good picture quality. And what about HDTV (high definition television)-isn't it right around the corner?

Crisp image quality, low weight, and portability have made digital light processing, or DLP, projection popular in the business market, from ultraportable projectors for on-the-road presentations to highbrightness systems used at trade shows. Since the technology was first unveiled in 1996, the world has become increasingly digital-with digital image capture, editing, and transmission seen in high-definition television, 64-bit gaming systems, digital cameras, and DVD-digital projection seems the next logical step. This year consumers will see the launch of large screen, HD-capable home entertainment systems based on Texas Instruments' DLP technology, which the company says provides higher contrast, color accuracy, and sharper video images than liquid crystal display or cathode ray tube-based systems. The DLP also offers size advantages, says the company, since it can be housed in a compact cabinet that is smaller than the enclosure required for a conventional large screen television.

"To display all the information which the family of the future will demand," says Dale Zimmerman, home entertainment project manager with Texas Instruments, "the screen will have to be large-which means that the CRT is unlikely to be able to compete without filling the entire living room." DLP enables the design of large screen systems, which can be housed in compact cabinets. LCD has not yet demonstrated that it can deliver acceptable video image quality of HD applications. "Plasma is everyone's idea of the TV on the wall, but it continues to be very expensive and still has a long way to go in terms of image quality," says Zimmerman.

Both Mitsubishi and Hitachi will use DLP technology in all-digital, large- screen, high-definition rear-projection television, which will go on the market this year.

Texas Instruments' digital light processing system consists of a light source, optics, color filters, digital processing and formatting, a digital micromirror device (DMD), and projection lens. It operates under an extremely simple principle. The DMD, an optical semiconductor chip that has 500,000 microscopic mirrors mounted on a standard logic device, is the heart of the system. Each mirror represents one pixel. These tiny hinged mirrors (480,000 SVGA, 786,000 XGA, or 1,310,000 SXGA) operate as optical switches-either reflecting light away from the lens (off) or through a lens (on) to create a high-resolution, full-color image. Electrodes under opposite corners of the mirror are activated by the incoming video or graphics signal and cause each mirror to tilt thousands of times per second. This structure yields pixels that can switch on or off more than 5,000 times per second in response to incoming digital signals. Each square micromirror is about 1/5th the thickness of a human hair. The gap between the mirrors is less than one micron, giving DLP images a seamless appearance. Light is either reflected through the lens onto the screen-in which case a white pixel appears- or away