MANAGING HIGHER HARMONICS IN A HEADPHONE

Koss Corporation's Pro 4AA Titanium Stereophones. Perfect sound reproduction is a kind of Holy Grail for all sound engineers. One challenge in particular for designers of dynamic headphones, which employ a thin diaphragm to create pressure waves, is to cope with sound distortion at high frequencies. In order to reduce the higher harmonics, Koss increased the 2-mil-thick polymer diaphragm's stiffness by adding a thin coating of titanium-following the lead of some other headphone makers. They also added sponge-like cushions to the adjustable headband, which they say seal closer to the ear to eliminate ambient sound and maximize base performance. Does it work? Users will have to try the stereophones out for themselves and see what they think. Marketing Services Manager:Jessica Pitroski, [email protected] (www.koss.com). Enter 533

LIGHT-WEIGHT BOTTLES REMAIN STRONG

CONSTAR International Fill Container. Thin-walled tubes, like water bottles, can buckle under high compressive loads. As markets change and water companies self- manufacture their own bottles, CONSTAR has been challenged to design and produce a more cost-effective, light-weight container while maintaining maximum crush strength to sustain the rigors of packing, storage, and shipping. The key: using Finite Element Analysis (FEA) software in combination with Z Corp.'s Z(TM) 406 Color 3D Printer (www.zcorp.com). FEA data predicts bottle failure points and the printer produces a 3D color model. CONSTAR's 500 ml bottle proved to withstand these performance tests and offers a competitive weight. Next in line for CONSTAR is a 1l and 20 oz bottle, both also made of PET that is inexpensive, lightweight, resealable, shatter-resistant, and recyclable. Lead Engineer:Mike Mooney, [email protected] ( www.constar.net). Enter 534

ELECTRIFIYING KART

ElectricLouie Electric GoKart. It takes a tough clutch to transfer up to 250 ft-lbs of torque from the motor to the drive wheels of this 144V high-efficiency-battery electric kart. The 6-inch Advanced DC (www.adcmotors.com) series-wound forklift motor can handle upwards of 800A for 3 seconds, for a 12-sec quarter mile and a speed of 102 mph (potential performance is 150 mph in 8 sec). With an electric motor, clutch components are more stressed at low rpms when it produces peak torque. And President Louie Finkle says mechanical clutches were too slow in actuation. "It had to shift within a couple hundred milliseconds, tops, not the half second or more of a mechanical clutch," he adds. Thus engineers needed a rugged, fast-acting clutch with minimal slip during launch that could be mounted on the output shaft. Finkle notes the economical solution was the Ogura (www.ogura-clutch.com) ST1W stock mobile electric clutch, "with its double flux armature design and heavy-duty construction and return springs." President:Louie Finkle, [email protected] (www.electriclouie.com). Enter 535

CLAWS AND EFFECT

Massa Products Corp. Robotic Lobster. Taking cues from nature, Massa and the Marine Science Center of Northeastern University (www.neurotechnology.neu.edu) are developing a mine-hunting biomimetic mechanical lobster for the Office of Naval Research. The reason: How better to operate in the swirling shallow water surf zone than to mimic an animal that walks and looks for food there? (Its claws actually generate down force in currents, keeping it from being swept away.) According to Sales Manager Al de Chiara, a lobster has just a brain stem and simple nervous system, yet is able to function effectively. "Because its functioning is simple, to duplicate it doesn't require lines and lines of computer code," he adds. CTO Don Massa notes the challenge of reverse engineering functions, "brain" processes, and autonomous behavior for object-oriented programming was met by NEU's Joe Ayers who plugged electrodes into the nervous systems of treadmill-walking lobsters to determine their motion control architecture. The current feasibility model moves by applied electric currents contracting wires made of Nitinol (a shape-memory nickel titanium intermetallic material) in its leg joints. Ultimate goal is a lobster controlled by a single PIC microprocessor with a run time of 12 hours. President /CTO:Don Massa, [email protected] (www.massa.com). Enter 536

MOUSE IN HAND

ErgoTouch RocketMouse. This patented interface device is "all about ergonomics and comfort to allow a user to kick back and relax, because he or she is not tethered to a surface to work it," says CEO Seth Alsbury. The shape fits over the fingers so the mouse is "worn and not held," he adds, although some users on our staff wanted a longer grip handle on the bottom. Alsbury notes the key design challenge was developing a trackball to work in a "mouse that is basically upside down, or in any orientation, within a small housing." A user's thumb controls the curser-moving trackball and the index finger triggers a switch for the traditional left-click functions. The thumb also activates the right-click button, as well as a unique scroll key (to the left of the right-click button) that works in conjunction with the trackball. The device aims to reduce tendonitis and repetitive stress injuries. CEO:Seth Alsbury, [email protected] (www.ergotouch.com). Enter 537

LIFESAVING MADE EASY

Medtronic Physio-Control LIFEPAK(R) CR Plus defibrillator. The Quik-Pak electrode allows the user to easily open the color-coded electrodes with one hand and place the pads on the patient suffering from sudden cardiac arrest. Once the adhesive pads are in place, the device will determine if there is a lethal heart rhythm and if a shock is necessary. Prompt defibrillation with an intuitive user interface, including voice and graphical prompts, as well as audible tones, enables a minimally trained user to save the life of a bystander in cardiac arrest. The device case, injection-molded with Accurate Molded Plastic's Bayblend(R) FR 110 resin (www.accurateplastics.com), and over-molded with urethane for a better grip is small, portable, and presumably more rugged than before. A top cover, made of Bayer Polymers' Makrolon(R) 2405 polycarbonate (www.bayerplastics.com), protects the electrode pads. Senior Systems Engineer:Tom McKay (www.medtronicphysiocontrol.com/products/LPCRPLUS.cfm). Enter 538