From the submitter:
I play games online on PSN, bluetooth headset kept getting lost, then I just hacked the two together. An effective fix! Full build log at the source.
Deviant Artist Midnight Angel put together an arm blade stylized after the ones used in the Assassin's Creed video game series. Using a drawer opening mechanism, a spring for a screen door, and a throwing knife, the weapon works surprisingly smoothly. The full instructions are on Angel's page, and you can see it in action below.