A method of creating a mechanical force switch to be disposed along a longitudinal axis of a medical device, comprising: providing a hollow body defining a body interior cavity with a longitudinal device axis; movably disposing a switching piston along the longitudinal device axis in the body interior cavity, the switching piston having: - a longitudinal piston axis disposed parallel to the longitudinal device axis; and - a bias-device contact; whereby the switching piston is movably disposed in the body interior cavity to define: - a switch-making piston position at a first longitudinal piston position with respect to the body; and - a switch-breaking piston position at a second longitudinal piston position with respect to the body that is different from the first longitudinal piston position, the method further comprising: coupling an electrically-conductive contact to the switching piston such that the electrically-conductive contact is moveable between the two piston positions to define a switch-making state, when the switching piston is in the switch-making piston position, and a switch-breaking state, when the switching piston is in the switch-breaking piston position; and imparting an adjustable longitudinal bias to the switching piston at the bias-device contact with a bias device to retain the switching piston in one of two positions selected from the switch-making piston position and the switch-breaking piston position until an external force imparted to the switching piston exceeds the longitudinal bias thereby forcing the switching piston to move to the other of the two piston positions, thereby providing the switching piston with an adjustable longitudinal pre-tension force that must be overcome before the force switch can actuate electrically, characterised by; the longitudinal bias imparted being an adjustable longitudinal bias to the switching piston at the bias-device contact. providing a hollow body defining a body interior cavity with a longitudinal device axis; movably disposing a switching piston along the longitudinal device axis in the body interior cavity, the switching piston having: - a longitudinal piston axis disposed parallel to the longitudinal device axis; and - a bias-device contact; whereby the switching piston is movably disposed in the body interior cavity to define: - a switch-making piston position at a first longitudinal piston position with respect to the body; and - a switch-breaking piston position at a second longitudinal piston position with respect to the body that is different from the first longitudinal piston position, the method further comprising: - a longitudinal piston axis disposed parallel to the longitudinal device axis; and - a bias-device contact; whereby the switching piston is movably disposed in the body interior cavity to define: - a switch-making piston position at a first longitudinal piston position with respect to the body; and - a switch-breaking piston position at a second longitudinal piston position with respect to the body that is different from the first longitudinal piston position, the method further comprising: - a switch-making piston position at a first longitudinal piston position with respect to the body; and - a switch-breaking piston position at a second longitudinal piston position with respect to the body that is different from the first longitudinal piston position, the method further comprising: coupling an electrically-conductive contact to the switching piston such that the electrically-conductive contact is moveable between the two piston positions to define a switch-making state, when the switching piston is in the switch-making piston position, and a switch-breaking state, when the switching piston is in the switch-breaking piston position; and imparting an adjustable longitudinal bias to the switching piston at the bias-device contact with a bias device to retain the switching piston in one of two positions selected from the switch-making piston position and the switch-breaking piston position until an external force imparted to the switching piston exceeds the longitudinal bias thereby forcing the switching piston to move to the other of the two piston positions, thereby providing the switching piston with an adjustable longitudinal pre-tension force that must be overcome before the force switch can actuate electrically, characterised by; the longitudinal bias imparted being an adjustable longitudinal bias to the switching piston at the bias-device contact.