IoT for Ninjas: An Arduino-Based eKatana for Martial Arts Training

Those looking to up their game in martial arts training, are perhaps looking to increase their Kendo prowess, or really just want to know what their quality of motion is while swinging a sword, should take a look a software engineer Carlos Justiniano’s eKatana.

Justiniano got the idea for his motion-tracking sword after looking back on his martial arts training and his interest in distributed communications in the context of IoT devices. Combining the two would be beneficial for those looking to gain insight on katana strikes and motion techniques.

The eKatana is built upon a BladesUSA polypropylene training sword that’s outfitted with an Adafruit LSM9DS0 sensor breakout board (accel/mag/gyro + temp) that grabs data from the motion of the sword while being swung. An Adafruit Feather 32u4 Bluefruit LE (powered by a Lithium-ion 3.7V 100mAh battery) processes the data and sends it wirelessly to an accompanying app that lets you view the results.

The data provided includes values for rotation (RO), pitch (PI), and heading (HD). As the sword moves, changes in those values can be seen in real-time, allowing to adjust your technique (or kata/form) in those areas.

The build seems relatively easy to recreate for those looking to improve their martial arts abilities. Justiniano provides all the necessary details on how to build your own eKatana, including all the hardware needed and the code to create the app. It’s not meant to be a complete tutorial, however he states those looking for more information are welcome to reach out with any questions you might have.

Side note: I have a friend that is a legitimate ninja. His tutelage was not on the top of a Japanese mountain, but by mail order. He would send in videos of himself performing “whatever,” and the instructor would judge it. I foresee that videos will not even be necessary soon for such things. Motion tracking is the future for martial arts.