Abstract: A defect centre-based sensor is disclosed. The sensor comprises instrumentation which includes a generator for causing excitation in an active element, for example a diamond, and a detector for measuring a transition in the active element. The generator is an optical source and/or the detector is an optical detector. The sensor further comprises an optical waveguide and a sensor head in communication with the source and/or the detector via the optical waveguide. The sensor head houses the active element having at least one defect centre, for example, a nitrogen vacancy, responsive to an applied magnetic field, electric field or temperature and a signal delivery arrangement, for example at least one lens, arranged to optically couple the optical waveguide to the active element.

Abstract: A device used for threading a seat belt through a child safety seat includes an elongated, double-ended threader member which is connected to the seat belt tongue and to webbing at a location spaced from the tongue. The webbing is then folded over to cover the threader member and the threader member is employed to push the tongue through a passageway in the child safety seat.