A method for initiating a thermal battery including: releasing an engagement between an element and a striker mass upon an acceleration time and magnitude greater than a first threshold; and moving at least one member into a path of the element to prevent the element from releasing the striker mass only where the acceleration time and magnitude is greater than a second threshold, the second threshold being greater than the first threshold.

The technology relates to techniques for an electromagnetic inertial switch. An electromagnetic inertial switch can include an electrically conductive and magnetic mass located within a cavity, where portions of the cavity are electrically conductive and are electrically coupled to terminals of the electromagnetic inertial switch. A first magnetic field can be configured to apply a first force on the mass to attract the mass towards a first location, and a second magnetic field can be configured to apply a second force on the mass to attract the mass towards a second location. The electromagnetic inertial switch can be in a first electrical state when the mass is in the first location, and in response to an acceleration event greater than a threshold acceleration, the mass can move to the second location, thereby changing the electromagnetic inertial switch to a second electrical state.

A sensor support assembly comprising a frame member adapted to be fixed on a vehicle structure and a support member adapted to be inserted in a recess defined in the frame member, the recess defining an axis along which the support member can switch from a normal position to a collapse position, the support member being guided during the displacement.

A sensor support assembly comprising a frame member adapted to be fixed on a vehicle structure and a support member adapted to be inserted in a recess defined in the frame member, the recess defining an axis along which the support member can switch from a normal position to a collapse position, the support member being guided during the displacement.