Smart Balls, tracking technology in sports coaching

The American science magazine; Popular Science recently posted an article regarding a new basketball sensor system. The system is able to track a player’s performance as they dribble, pass or make a shot, although from the article it is unclear whether this system is legal for use during competition or strictly training only.

Sensor systems in sport

Hawkeye is a familiar sensor system used for a number of sports, not only to govern the game (line-calling in tennis for example) but also to provide metrics and visualisations for a modern television audience hungry for stats. However, accurate multi-camera systems such as Hawkeye come at a great cost in terms of use and installation.

What is interesting about the new basketball sensor system is that it is contained within the ball itself. The company behind the technology, 94Fifty, is a startup from the University of Michigan and aims to provide an affordable coaching system for basketball teams at all levels.

The difficulty in embedding a sensor in a sports ball is that it has to be substantial enough that it won’t be damaged during the rigours of play, but also light enough that it does not affect the behaviour of the ball in any significant way.

The Adidas intelligent ball is an example of sensor integration into sport equipment - ruled out by FIFA

The sensor must also either log all of the information it is capturing (meaning analysis has to be conducted after play has finished) or it has to transmit captured data wirelessly during use. The information on the 94Fifty website suggests the sensor system is wireless, giving metrics of a basketball shot seconds after it has been made. It can detect (among many other things), the instant the ball is caught, the instant it is release, its angle of release, it spin, and angle of entry into the basket (although cannot detect whether the ball entered the basket or bounced off of the rim). It can perform all of this in a sensor package which apparently only weighs 5 grams, impressive stuff.

Cheaper sensor systems

My best guess at how this is achieved is through the same kind of technology that is present in the almost ubiquitous Wiimote.

The push for a wider audience has led gaming console manufacturers into using more intuitive and exciting interfaces. The use of sensor systems (such as accelerometers and rate gyroscopes in the wiimote, and more recently 3D sensing technology in the Microsoft Kinect ) in their devices has seen a corresponding drop in cost, benefiting completely unrelated areas of industry and research.

The Potential

An accelerometer and gyroscope array packaged into a basketball could yield a wealth of information to a user when coupled with sufficiently clever pattern recognition algorithms, which 94Fifty claim to have developed with patent-pending. A pattern recognition algorithm takes the acceleration and rotation data from the sensor system and identifies behaviour from the tangle of information. For example, a sudden spike in acceleration could be a catch, bounce or shot attempt. When an accelerometer is only registering gravity, the ball is in free flight. It’s quite a challenge to develop a robust set of algorithms to decipher the many varied play behaviours in basketball.

This technology becomes really exciting when adopted for use during competitive play. Recording the metrics of the worlds best players not only provides more informative stats to feed an audience but also drives a massive data-collection effort which could provide a wealth of associated research.

Here’s hoping we’ll soon see this kind of technology in a number of different sports.

Simon Choppin


About wiredchop

Simon Choppin Simon’s sports engineering career began at the age of six when he loosened the wheels of his skateboard in order to make it go faster. While the experiment was chalked up as his first failure, his resulting dimpled skull has provided an aerodynamic advantage in more recent sporting pursuits. Academically, Simon completed a degree in Mechanical Engineering with Mathematics at Nottingham University before joining the Sports Engineering Research Group at Sheffield to start his PhD. His main interests include work with high speed video, mathematical modelling of various sorts and experimental work involving machines with big buttons. As a sportsman, Simon has an unfortunate lack of talent for anything requiring skill, tactical awareness or the ability to learn from mistakes. He does however seem to posess the ability to move his legs around for a long time until other people get tired, for this reason you’re most likely to see him on a bike of some sort or running up a hill in offensively small shorts. Simon was fortunate enough to have a stint at the Guardian newspaper as part of the BSA’s media fellowship, which gave him the idea for this blog. Other than this, his writing experience includes his PhD thesis and various postcards to his Mum.

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