Sensor fusion and integrated MEMS are essential tools for today’s athletes

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A golfer stands in the dreaded sand trap, carefully considering how to balance his weight as he eyes the ball. He takes a few practice swings. If he swings too deeply, he’ll hit the ground and lose another stroke. It’s a tough shot, but he swings without hesitation. Embedded in his club are microelectromechanical system (MEMS) devices—tiny machines with elements about the thickness of a human hair. These devices aren’t going to swing the club for him, but he’s been using them to analyze his swing and practice this shot. Maybe this time he’ll make it.
mjcymdkzmgThe wild popularity of smartphones and wearables has been driving down the cost of MEMS devices, including accelerometers, gyroscopes, magnetometers, and pressure sensors. These minuscule chips help to count steps, track calories burned, and monitor heart rate. Such data are useful, sure, but while these devices may nudge users to be more active, they don’t actually improve a swing, a punch, or a kick. To do so means moving sensors off the wrist and into sports gear—and that’s quickly happening. Indeed, you can now buy sensor-based equipment that can boost your performance, not only for golf but also for tennis, baseball, boxing, and soccer.

Equipment: Babolat Pure Drive Play racket

Sensors on board: InvenSense motion-sensing system embedded in its handle

What it tracks: Type of shot made (forehand, backhand, serve, and smash), location where the tennis ball connects with the racket’s strings, overall playing time versus active playing time, and ball speed during play and when serving

How it works: Players can connect the racket via Bluetooth to a mobile device to share data with a coach for postgame analysis or over social media.

Commercial status: Announced at French Open 2013; available now at US $200

Manufacturer: Babolat

Measuring the often-complex motion of an athlete takes many more metrics than just tracking steps. Consider the sport of sculling: To gauge the efficiency of a rower as his oar moves through the phases of catch, drive, release, and recovery, you need to track the movement of his legs, back, and arms. If you want to analyze a baseball player as he whips the bat around, you need to consider rotational angles and swing speed.

The current boom in sensor-laden sports equipment is an outgrowth of the dramatic drop in sensor prices and the development of technology that makes it easy to integrate data from multiple sensors. In the past, synthesizing the data outputs from multiple sensors in real time was a nightmare. Figuring out how to make sense of streams of data flying into a general-purpose processor—so-called sensor fusion—presented a real hurdle to developing sports-training products that used such data, even though the need was clear.

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