An accelerometer system comprising: a first magnetic assembly comprising a first pole piece and a first magnet; a second magnetic assembly comprising a second pole piece and a second magnet; a proof mass between the first magnetic assembly and the second magnetic assembly; a first coil disposed around the first pole piece; and a second coil disposed around the second pole piece; and processing circuitry configured to: cause a first current to flow through the first coil to apply a first Lorentz force to the proof mass; cause a second current to flow through the second coil to apply a second Lorentz force to the proof mass; and limit a maximum amplitude of the first current and the second current for at least a threshold period of time.

A hermetically-sealed multi-directional single-proof-mass accelophone that demonstrates a high sensitivity to micro-gravity level accelerations in a wide operational bandwidth by utilizing nano-scale transductions gaps and vacuum packaging. Stable operation of the wafer-level-packaged sensor is validated over a wide operational bandwidth greater than 10 kHz. Developing a noise-matched custom interface IC should enable a sensor noise performance near the Brownian noise floor of below 10 g/Hz. The sensor can be applied in detection of vital mechano-acoustic signals emanating from the body and can be easily incorporated in existing wearable health monitoring devices for multi-faceted health monitoring using a single integrated sensor.

A micro-electro-mechanical system (MEMS) motion sensor is provided that includes a MEMS wafer having a frame structure, a plurality of proof masses suspended to the frame structure, movable in three dimensions, and enclosed in one or more cavities. The MEMS sensor includes top and bottom cap wafers bonded to the MEMS wafer and top and bottom electrodes provided in the top and bottom cap wafers, forming capacitors with the plurality of proof masses, and being together configured to detect motions of the plurality of proof masses. The MEMS sensor further includes first electrical contacts provided on the top cap wafer and electrically connected to the top electrodes, and a second electrical contacts provided on the top cap wafer and electrically connected to the bottom electrodes by way of vertically extending insulated conducting pathways. A method for measuring acceleration and angular rate along three mutually orthogonal axes is also provided.