Abstract: A trigger mechanism including sensing electronics, a power source and a length of bifilar wire. The bifilar wire has two electrically conductive filaments separated by an insulator, with a first end in electrical connection with the sensing electronics and the power source and a second end that is free. A circuit can be created by fusing together the two filaments in a section of the bifilar wire. The sensing electronics are configured to monitor the status of a circuit created between the bifilar wire, sensing electronics and power source and to output a signal when the circuit is broken.

Abstract: A method for attaching a surface mountable unit to a ground surface, said method comprising (i) fixing a foundation frame, an upper portion of which is attachable to said surface mountable unit to the ground surface, and (ii) attaching the surface mountable unit to the upper portion of the foundation frame. Systems comprising combinations of foundation frames and surface mountable units and elements for use therein are also described and claimed.