Technology gets on the ball

DN Staff

April 6, 1998

6 Min Read
Technology gets on the ball

St. Louis--Engineering is enhancing the enjoyment of weekend warriors in both baseball and tennis. Here's the lowdown:

With winter's grip easing, young men (and women) take to the greensward once again to practice the religion, nee sport, of baseball. This season many come armed with a new tool to enjoy and perfect their game, the Rawlings Radar Ball(TM). While the name capitalizes on what the company calls "accepted terminology to denote measuring a pitcher's arm speed," the microchip equipped sphere is not a radar-emitter. Instead it's an elegant timing and display device. Rawlings has licensed the electronics for baseballs and softballs.

To use the Radar Ball, a pitcher taps the ball once, turning it on and setting the liquid crystal display (LCD) to zero. When the pitcher throws the ball, the release impulse again triggers the inertial switch, activating the processor. Impact with the catcher's glove stops the timing function. The software converts time to travel the set distance into speed and displays it on the LCD. This readout is retained whether the catcher drops the ball or tosses it back to the pitcher. Only when the pitcher taps the ball three times in sequence does it reset for the next pitch.

The Radar Ball comes in three models: the 46 for youth leagues calibrated for the 46-ft distance from the pitching rubber to home plate; the 60 for the official 60-ft 6-inch distance, which has a raised seam for enhanced pitch control; and the Pro model, unavailable to the public, with the flat seam of major league baseballs.

New switch: key and challenge. Scott Smith, marketing product manager for Rawlings, notes the Radar Ball received a great reception when taken to the Los Angeles Dodgers spring training camp last year, but "building a hand-made prototype and translating that into production of hundreds of thousands is no easy task."

The inertial switch design is critical, and it had to work for many users. "The switch has to be resilient since few people throw the ball the same way as a matter of style, and age differences." He adds research is underway to make sure the switch is adequate for underhand softball use.

Radar Ball inventor Dave Zakutin, who developed it as a graduate thesis project, notes the critical technical challenge was one universally taken on by design engineers, "having it work well and within a limited budget and price point." Zakutin designed and patented a switch for manufacturing ease that would satisfy performance and cost needs. "Existing switches needed several precision components--spring, mass, damper, and contact--and came in very high at $5 each in volume." He describes his switch as a single-piece "cantilever spring with a thin enough wire" within a hollow barrel having low-cost seals of Dupont Delrin(reg) acetal resin. "Assembly is cost effective, since spring making has been around a long time, with the switches coming in at under a dollar," he says. Other applications for the switch, Zakutin notes, "are anything that requires a single input command from a single-pole sealed switch," from alarm clocks to perhaps simplified airbag-type switches.

Aerodyne Controls (Ronkonkoma, NY) makes the Radar Ball switches. "We caught up with them at the right time," says Zakutin, because the firm was looking for work after the downturn in its traditional aerospace-based business. The balls are made in China and shipped to Kyooh Precision Industry Company (Taipei, Taiwan). Technicians core and stuff them with a 1.5-V watch battery, the switch, and a 3/4-in deep electronics module. The latter consists of a 4-bit microprocessor from S-MOS (Tokyo), which runs at the 32 kHz watch frequency, and a Chinese-made LCD.

"The display is the weak link," Zakutin notes. "We looked for plastic LCD displays, but right now these are only being made for larger laptops. Still, you can't break the glass-based display even throwing the ball against a wall, except for a direct impact on the LCD." Using a bat on the Radar Ball voids its warranty. To resist abrasion when dropped or bounced, the plastic LCD cover has a protective film of thin (0.008 inch) urethane tape from 3M, similar to that applied on some airliner undersurface skins. A packet of peel-off replacement tape appliques is included with the ball.

Next along the lines of the Radar Ball could be a slap-shot-speed sensing hockey puck. Zakutin adds, "We are also bringing technology into sports to measure things done subjectively before. The Radar Ball can measure performance and thus monitor rehabilitation from injury." With additional development of low-cost rotation sensors and hardy accelero-meters, spin determination could be done and applications extended to golf balls. But for now, turn on, tune in, and "Play ball!"

More powerful swings. When Po-Jen Cheng joined Wilson sports as Director of Rackets Technology a few years back, a typical tennis racket weighed about 12.6 oz. In contrast, the company's newest racket, the Hammer Extreme 3.2, is a mere featherweight at 8.9 oz. And that is helping average players like Cheng play somewhat better than average.

That's because they're hitting the ball harder, even though they're using a lighter weight racket. "We strategically redistributed the weight of the Hammer rackets, placing more mass in the head," explains Cheng. More mass at the point of impact means more efficient delivery of energy, keeping more balls in play longer.

The weight redistribution also maintained the racket's moment of inertia so that it swings like a traditional light-weighted-head racket. The balance point on the 27 inch-long racket, explains Cheng, is 2.75 inches further away from the tip of the handle than before. That helps to make the racket easier for players to maneuver.

"It's more comfortable to swing, yet at the same time easier to control," says Cheng, "All you have to do is flick it and the moment takes over. Even average players can really whack the ball."

Another innovation on the Hammer Extreme 3.2 is the elongated string holes, called Power Holes, which are designed to produce a larger sweet spot and provide more power on off-center hits. But why not just simply enlarge the head of the racket?

"We're constrained by the 135-sq-inch limit on head size set by the International Tennis Federation," Cheng says. "Besides, the bigger you make the head, the more unwieldily the racket can become."

So instead, engineers came up with the clever idea of changing the geometry of the grommet holes. They took the usual 1.7 mm diameter holes and elongated them into elliptical shapes measuring 10 mm long by 3 mm wide. These oversize holes allow the strings to move freely upon impact, effectively increasing the actual string response area by over 21.5%.

With the strings behaving as if they were longer and more resilient, less energy is lost through the spring effect. Again, more energy transfer to the ball.

One other noteworthy feature of the new racket, which is made of 100% graphite/epoxy, is the use of titanium as a bonding agent in the resin. "Graphite composites are strong only in a specific direction in which the fibers are oriented," says Cheng. "By using titanium in the bond, we're making the frame stronger in all directions."

In the end, Cheng wont guarantee that the racket will work miracles for a lousy player. But he did stress that for the $219.99 price of the racket, the average tennis buff is getting a lot of bang for the buck.

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