MEMS gyroscopes are making significant progress towards high performance and low power consumption. They are mass produced at low cost with small form factor to suit the consumer electronics market.
MEMS gyroscopes use the Coriolis Effect to measure the angular rate, as shown in
When a mass (m) is moving in direction v→ and angular rotation velocity ?→ is applied, then the mass will experience a force in the direction of the arrow as a result of the Coriolis force. And the resulting physical displacement caused by the Coriolis force is then read from a capacitive sensing structure.
Most available MEMS gyroscopes use a tuning fork configuration. Two masses oscillate and move constantly in opposite directions (Figure 2). When angular velocity is applied, the Coriolis force on each mass also acts in opposite directions, which result in capacitance change. This differential value in capacitance is proportional to the angular velocity ? > and is then converted into output voltage for analog gyroscopes or LSBs for digital gyroscopes.
When linear acceleration is applied to two masses, they move in the same direction. Therefore, there will be no capacitance difference detected. The gyroscope will output zero-rate level of voltage or LSBs, which shows that the MEMS gyroscopes are not sensitive to linear acceleration such as tilt, shock, or vibration.
MEMS gyroscopes can measure angular velocity. Digital cameras use gyroscopes to detect hand rotation for image stabilization. A yaw rate gyroscope can be used in cars to activate the electronic stability control (ESC) brake system to prevent accidents from happening when the car is making a sharp turn. And a roll gyroscope can be used to activate airbags when a rollover condition happens.