This Sensor Is a Game Changer

As the greatest athletes in the world once again assemble for the Olympic games, we are reminded just how intensely competitive professional sports can be. Gaining even a small edge over another competitor can make the difference between standing tall on the world stage and being sent back home for another four years. So to keep their skills sharp, professional athletes spend a lot of time practicing their craft to improve their skills. But when one achieves a very high level of performance, it can be difficult to even notice the small, incremental improvements that are achieved through practice. So many athletes and trainers are increasingly turning to technology to monitor and perfect a wide variety of skills.

Wearable sensors have proven to be very valuable for applications such as this. They can precisely measure movements of the body in real-time, providing instant feedback to the athlete. Even things that may be too small or too fast to be noticed by a human trainer can be detected by these devices, enabling a much finer level of skill tuning than would otherwise be possible.

However, if they are not carefully designed, the wearable sensors themselves can get in the way and interfere with training and performance improvement. That may be less of a concern in the future, however, as a result of the work of researchers at Lyuliang University. They have developed a comfortable sensing system for athletes that can bend and twist without restricting joint movement. The sensors are also self-powered and have been shown to be quite accurate.

Badminton may not be the most popular sport, but it is known as a game that requires a great deal of speed and precision to excel at. The whole body is involved in badminton, from precise footwork to exacting arm swings. It is for this reason that the researchers built their sensing system, initially at least, to monitor badminton players.

A key component of the approach involves the use of triboelectric sensors. These sensors make use of disparate materials that transfer an electric charge from one to the other when they come into contact. The amount of charge that is produced can be used for sensing movement of the body part that they are attached to. The materials themselves generate this charge as they slide past one another, so no batteries or external sources of power are needed, which makes the triboelectric sensors small, flexible, and comfortable to wear.

The first sensor of this type designed by the team was a 3D-printed flexible arch that can be worn in the shoe. It was encased in a thermoplastic elastomer to minimize sources of interference and enhance its sensing accuracy. While not yet proven, it is believed that the same methods should also work for measuring movements at the wrists, elbows, shoulders, fingers, knee joints, and other regions of the body.

To make sense of the data captured from the sensor, the researchers developed a neural network classifier. It was trained to recognize a number of badminton moves, such as the forehand serve, backhand serve, forehand hook, and backhand hook. Experiments revealed that this system correctly classified the moves in 97.2 percent of cases.

This work proves that on-body sensing solutions can be unobtrusive and yet provide accurate results. With some refinement, this technology may be able to be adapted to work for other sports, or even for a variety of health monitoring applications.