MEMS Inertial Sensors

Gyroscope is a part of inertial navigation system, for measuring the angular velocity of the rotating object.
It is used to maintain the orientation of an object in any specific direction.
MEMS gyroscope is a vibrating structure gyroscope based on Coriolis Effect.
MEMS gyroscope consists of a mass which is usually allowed to vibrate in an axis and the rotation is applied perpendicular to this vibrating axis. As result of Coriolis Effect, the mass will experience a displacement perpendicular to both the vibration and rotation.
This displacement after decoding gives the amount of rotation experienced.

Seismometers are instruments used to detect and quantify motions on the ground including those generated by quakes and volcano eruptions.
Seismometers operate on the principle of inertia – stationary objects remain stationary unless an external force is applied to them.
MEMS Seismometer is made using Silicon on Glass (SoG) architecture.
A proof mass is suspended by folded cantilever beams, with comb electrodes projecting out of the proof mass at right angles.
The cantilever beams are anchored to the outer casing at its four respective ends.
The proof mass with electrodes is movable and is designed to be sensitive to ground vibration in one direction.
Sensitivity in one direction is due to the rectangular cross-sectional shape of the suspension beam.
The low width of the beam compared to the length and thickness makes it more compliant in the sensing direction, and hence more sensitive to applied forces along that direction.