US Patent 7305882 Accelerometer using magnetic transducer technology

The accelerometer uses magnetic transducer technology. A mass-block, mounted to a base by an elongate member (shaft), moves relative to the base due to accelerations. The elongate-member has at least one magnetised transducer region (circumferential or longitudinal), which emanates a magnetic field as a function of member flexure due to acceleration of the mass-block. A sensor adjacent the transducer detects the field and derives a acceleration-representing signal. Alternatively, a mass-block is mounted to a central hub of a disc which is radially secured and has an intermediate region that flexes in response to acceleration. The intermediate region is magnetised to provide the magnetic transducer element. Otherwise, the mass-block is supported in an aperture of a reference-base by cores of inductors. The core permeability is a function of the compressive tensile forces on the cores due to acceleration of the mass-block. Resulting acceleration-dependent inductance changes provide signals for deriving an acceleration-representing output.