How to play tennis…with the Internet of Things

In recent years, technological advancements through the Internet of Things (IoT) have opened doors to new, smart ways to do sports. We can drastically improve the way we practice and play, even competitively – allowing those using IoT-enabled sports equipment to gain a competitive advantage.

Not limited to sports, an IoT-enabled device is a “thing” that communicates and syncs with other “things” – all of which are connected (via internet or other connectivity options like Bluetooth or cellular). These can include smartwatches, voice assistants, security cameras and even smart home appliances like coffeemakers or washing machines.

But using IoT devices in sports has become a particularly interesting subject. Because in sports, using smart equipment and applications helps users track performance, monitor progress and ultimately improve their skills as athletes.

Introducing smart tennis

Let’s take a look at the game of tennis, which is quickly changing due to the arrival of smart connected rackets.

Throughout history, tennis players typically made rough guesses as to how hard, with how much and what type of spin, and how closely to the center of the racket’s strings they hit the ball. There was no way to use a quantitative approach to assess precisely what progress they were making in strengthening their abilities.

But now, the emerging capabilities of IoT have made smart tennis rackets a reality. These rackets accurately measure hit strength, ball spin and the position of the ball when it hits the racket, transmitting data to a smartphone application that analyzes the player’s performance.

The history of smart tennis rackets – Overcoming challenges

The mid-sized company, Babolat, invented smart rackets that brought tennis into the technological age. A company that specializes in tennis equipment and has been doing business since 1875, Babolat announced their new IoT-enabled racket, the Play&Connect, in 2012.

But creating the Play&Connect wasn’t a simple task; the company faced difficult challenges along the way. The main challenge initially was the need to make smart rackets play exactly like regular rackets – even the best rackets on the market – by feeling comfortable and natural in the player’s hand. Otherwise, many tennis players (especially the most skilled veterans) would never use them.

To that end, Babolat engineers had to find a small, light sensor solution that accurately tracks the motion of the tennis racket, boasts low power consumption and can withstand large shock loads – all while being unobtrusively designed into the racket. Babolat turned to the InvenSense MPU-6000 integrated 6-axis motion tracking device, which combines a 3-axis gyroscope sensor, 3-axis accelerometer sensor and associated electronics in a 4 x 4 x 0.9 mm package – weighing only a single gram. The two sensors do the following:

• Accelerometer sensor – Tracks the acceleration of the racket to determine the speed of the racket at the moment it contacts the ball, allowing the ball’s speed to be calculated
• Gyroscope sensor – Determines the orientation of the racket which, in combination with the racket speed, determines the amount of spin on the ball

To embed the motion tracking device into the handle, Babolat engineers had to reduce the weight of the tennis racket to compensate so the racket’s center of gravity would not change. This was particularly important, since the racket needs to feel natural when wielded by an experienced tennis player.

Getting the information across – Algorithms, algorithms, algorithms

To send the calculated information to the player, Babolat’s smart rackets include a microprocessor that collects data from the MPU-6000, the on-board data storage and a Bluetooth module, transmitting information to the player’s smartphone.

To make this happen, the racket needed to have the right algorithms. This was a major challenge, as the algorithms needed to be able to translate sensor data into useful data that tennis players can actually use to improve.

Among the chosen algorithms is one that determines the ball’s point of impact on the racket. As it is essential for tennis players to hit near the central string area – referred to as the “sweet spot” – this was a particularly important feature to include. The further the impact is from the “sweet spot”, the greater the vibration magnitude caused by the impact, which can potentially throw off the expected trajectory of the ball. In addition, a non-“sweet spot” impact causes the racket to rotate immediately after the hit, which is particularly important for smart rackets. To identify the success of hitting a sweet spot, the sensors detect the speed of this rotation, alerting the player that the “sweet spot” was missed and by how much. Since it is impossible to place sensors directly on the strings, developers discovered the impact location can actually be calculated by combining the readings of the gyroscope and accelerometer sensors.

After receiving the data from the racket to a smartphone, the player can see a general overview, including information like the length of each rally, number of shots per minute, and number of forehands, backhands and serves. The player can then scroll down to see swing power, ball speed, the percentage of spin on the ball and the ball’s impact location for the entire session, for a particular type of shot, or even for individual shots. All performance data can then be compared with past data to see the player’s progress over time.

Smart sports today and tomorrow – Going beyond tennis

While still a somewhat new concept, tennis rules today allow the use of smart rackets in any official competition – but do not allow players to look at the data during the game. And since the introduction of the first smart racket, other companies have started to follow in Babolat‘s footsteps, among them Head, Prince, Wilson and Yonex.

But tennis isn’t the only area in the world of sports that has started to incorporate IoT technologies into player equipment. Here are some other examples:

• Wilson X Connected Football – A small sensor in the middle of the ball records the player’s throwing velocity, spin rate, spiral efficiency, distance, catches and drops, while the ball connects to an application
• Athos Wearable Fitness Technology – Tight-fitting clothing that is filled with sensors that detect the wearer’s heart rate, breathing rate and muscle activity
• 94Fifty Smart Sensor Basketball – A ball with internal sensors that measure the player’s shot speed, spin, arc as well as dribbling count and power, sending data to an application to instantly analyze and provide feedback on the player’s strengths and areas of improvement (and works with another product, SmartNet, that measures shot accuracy)

It’s clear that IoT has made a profound impact on the sports equipment industry, making equipment more useful for players who want to sharpen their skills. And as time marches on, more companies are sure to take the next step and see what IoT can do for their products.

As an experienced technology company, Zoreza Global can help make your IoT ideas a reality. Be sure to contact us to find out how IoT and other technology areas can benefit your business and keep your enterprise competitive.

Andrey Povarov,
Division Manager on premium learning service