Overview_Splash2My MSc thesis project, in service to the Stichting Nunchaku Nederland / World Nunchaku Association, aimed to develop a form of decision aid technology for the combat sport nunchaku-do.

Nicknamed ‘Hikari’ (光, Japanese for ‘light’), the primary goal of my thesis project was to develop a way for successful attacks to be detected over the course of a nunchaku-do sparring match. A decision was made to integrate this detector inside the weapon itself, so as to retain the ability to score anywhere on the opponent’s body.  However, fighters are constantly gripping the same area of the weapon that they use to strike, and ruling out false positives thus requires a particularly smart sensor application.

Velostat, a piezoresistive material which is gaining popularity in the maker movement, was identified as a promising smart material to develop an embedded pressure sensor. Through an intuitive tinkering process, the properties of the material were learned, and a custom grid-based sensor was eventually developed.

The performance of the sensor was validated through a series of experiments, where the sensor’s readings were compared to high speed recording of particular actions that could take place during a match. The image below shows, for every 10 milliseconds, what one of the nunchaku’s two handles will pick up. (One frame image shows two sides of the same handle.)


While still in need of further development, the sensor technology has already proven its potential as a decision aid and a useful application of smart materials. As such, it will be the subject of a soon-to-be-published paper, and receive an appearance at an emerging materials exhibit come June.



Supervisors: Johan Molenbroek (chair), Bahar Barati (mentor), Milco Lambrecht (company mentor)