https://www.mdu.se/

The study focuses on creating a self-defence device offering different types of protection possibilities in one device that is also legal in the EU, more specifically in Sweden. 

I research how much force a device would have to endure in case it is used for defending oneself in an attack, where should it be placed, what type of functions are legal to be used, what materials it needs to be made of and which functions customers would wish to have in a self-defence device.

The methods used to develop the product are a Gantt-matrix, a customer survey, a PDS, a benchmarking matrix, sketching and the Magic Thing-method for concept generation, interviews with experts, a function analysis tree, a Pugh’s Matrix, CAD-prototyping, FEM simulations and an FMEA analysis.

The resulting product comprises of a forearm length protective sleeve with an audio emitting device that is placed on top of the hand. The sleeve is made of steel mesh and polyester, protecting the user from knives and other slicing weapons. On the upper side of the forearm the sleeve has an optional panel made of Kevlar. The audio emitting devices has a built-in trigger on the side of the user’s palm, triggering the built-in audio track from the device immediately when the user makes a fist or otherwise presses the trigger. The sound emitted has a volume of 97dB and is comprised of panic stricken high pitched human screams with the intention of both confusing the attacker and to alert nearby people to help. 

The functions of the device are greatly narrowed down due to law, and other legal self-defence functions such as a blinding, non-laser light are not suitable to be emitted from a device this small, but the device can be further developed outside Sweden by adapting it to legislation of countries where more self-defence functions are legal.