A device for enabling safe/arm functionality in a gravity dropped weapon detachably connected to an airframe. The device including: an elastic element disposed in a shell of the weapon; a releasable connection between the weapon and the airframe to release a stored and/or generated energy in the elastic element; and a piezoelectric member connected to one end of the elastic member for converting the one or more of the stored and generated energy to an electrical energy. Wherein the releasable connection includes: a link having a movable connection for movement of the link relative to the shell between a first position constraining the elastic element from movement and a second position releasing the elastic member to generate the electrical energy; and a lanyard for tethering the link to the airframe such that the link is moved to the second position upon the weapon being released from the airframe.