Difference between Accelerometer and Gyroscope | Accelerometer vs Gyroscope

This page compares Accelerometer vs Gyroscope and mentions difference between Accelerometer and Gyroscope.


MEMS Accelerometer

• Accelerometer sensors are available in one, two or three axis models.
• They are used to detect magnitude and direction of acceleration.
• Applications: Three axis versions are used in smartphones while two axis versions are used in cars.
• High sensitive accelerometer sensors can measure acceleration more easily compare to low sensitive ones.
• Accelerometer can be used as tilt sensor but not all tilt sensors are used as accelerometers e.g. mercury based tilt sensor can not provide measurement of acceleration.
• Accelerometer works based on Newton second law of motion i.e. F = m*a,
where 'a' is acceleration, 'F' is applied force to the mass 'm' attached to the wall through spring (having coefficient 'k').
• The figure-1 depicts part of internal structure of MEMS accelerometer. It is similar to spring mass system. Refer Working operation of accelerometer >>.


MEMS gyroscope-A tilt sensor

• Definition: The device which is used for navigation and angular velocity measurement is known as Gyroscope. The Gyroscope made using MEMS technology is known as MEMS gyroscope.
• The MEMS gyroscope uses very small vibrating mechanism to detect changes in orientation. The gyroscopes can measure rotational velocity of one, two or three direction axis. 3-axis accelerometer is used to implement 3-axis gyroscope.
• There are various types of gyroscope viz. Mechanical Gyroscope, electronic gyroscope, MEMS gyroscope etc.
The figure-2 depicts MEMS gyroscope. Refer Working operation of MEMS gyroscope >>.

Difference between Accelerometer and Gyroscope

Following table summarizes difference between Accelerometer and Gyroscope.

Specifications Accelerometer Gyroscope
Function Senses linear movement, but worse for rotations, good for tilt detection. Measures all types of rotation, but not movement.
Signal to noise ratio Lower Higher
Measurement of angular velocity It can not measure rotation around its own axis of movement. It can measure angular velocity.

Conclusion: From the difference between accelerometer and gyroscope we can conclude that both of them have their specific functions. Accelerometer senses axis orientation where as gyroscope senses angular orientation. Moreover, combined solution of accelerometer and gyroscope in as single device helps in both rotation and movement tracking. They are used in conjunction with magnetometer. This combined sensor system consisting of accelerometer, gyroscope and magnetometer is known as IMU (Inertial Measurement Unit). The IMU is used for complete motion control of aircrafts, satellites etc.

Refer application note on interfacing of Gyro sensor >> with arduino uno board with pin to pin block diagram and source code.

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