Understanding IMU Sensor Working : Accelerometer, Gyroscope & Magnetometer in electronics
Introduction : An Inertial Measurement Unit (IMU) is a crucial sensor in modern technology, enabling accurate motion tracking and orientation detection. It integrates three primary components viz. accelerometer, gyroscope and magnetometer. Each plays a unique role in capturing linear acceleration, angular velocity and magnetic field orientation, respectively. This guide delves into how these components work together to make IMU sensors an essential part of devices like smartphones, drones and fitness trackers.
What is IMU (Inertial Measurement Unit)?
• The single unit which houses an accelerometer and a gyroscope is known as IMU or Inertial Measurement Unit.
It may also contain magnetometer.
• It provides necessary data to maneuver aircraft, spacecraft and watercraft especially when GPS signals are
not available.
Let us understand sub units of IMU viz. accelerometer, gyroscope and magnetometer.
➨Accelerometer is a sensor which measures acceleration as well as gravity.
➨gyroscope measures rate of rotation of the device (i.e. angular velocity) in which it is mounted.
➨Magnetometer measures magnetic field surrounding to itself. This helps in determining its orientation
relative to the magnetic field of the earth.
Accelerometer
Definition : Acceleration refers to rate at which velocity changes over time. Accelerometer is a sensor which measues acceleration as well as gravity. Its output is in units of gravity (i.e. letter 'g').
• It is used in the mobile phones to determine orientation of the phone with respect to ground.
This helps to rotate the picture or screen display appropriately for user to view.
• Now-a-days accelerometer is packed along with gyroscope and magnetometer.
• The figure-1 depicts accelerometer implementation using MEMS.
➨Refer accelerometer basics and working >> and
advantages and disadvantages of accelerometer >>.
Gyroscope
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 gyroscope implementation using MEMS.
➨Refer MEMS Gyroscope >> and
difference between accelerometer and gyroscope >>.
Magnetometer
Magnetometer is a device used to measure magnetic fields present around us. Magnetic fields are generated by current carrying conductor.
• The magnets creates magnetic field.
Even our earth has its own magnetic field. Earth's magnetic field strength is proportional to 1/r3.
• Magnetometer is classified into various types viz. vector magnetometer, scalar magnetometer,
Coil Magnetometer, Hall Effect Sensor Magnetometer, Magneto-resistive, Magneto-strictive, Fluxgate,
Overhauser, Optically pumped Magnetometer etc.
• The figure-3 depicts Earth magnetometer.
➨Refer Magnetometer basics and types >> and
advantages & disadvantages of magnetometer sensor >>.
Conclusion
IMU sensors, powered by accelerometers, gyroscopes and magnetometers, have transformed how we perceive motion and orientation in various applications. From enhancing navigation in autonomous vehicles to revolutionizing gaming and fitness, their versatility is unmatched. Understanding their working principles not only highlights their importance but also opens doors to innovative applications across industries.