Consider the following actions: 1. Detection of car crash/collision

Consider the following actions:

  • 1. Detection of car crash/collision which results in the deployment of airbags almost instantaneously.
  • 2. Detection of accidental free fall of a laptop towards the ground which results in the immediate turning off of the hard drive
  • 3. Detection of the tilt of smartphone which results in the rotation of display between portrait and landscape mode

In which of the above actions is the function of a gyroscope is used?

1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
This question was previously asked in
UPSC IAS – 2023
The correct option is D, indicating that the function of a gyroscope is used in all three actions.
A gyroscope measures angular velocity (rate of rotation). In modern devices, gyroscopes are often used alongside accelerometers (which measure linear acceleration and tilt due to gravity) in Inertial Measurement Units (IMUs) to determine full 3D orientation and motion.
1. **Car crash/collision:** Advanced automotive crash detection systems use IMUs containing both accelerometers and gyroscopes. While accelerometers are crucial for detecting sudden deceleration (impact), gyroscopes can provide data on the vehicle’s rotation (pitch, roll, yaw) during a crash sequence, which is vital for determining the severity and type of crash (e.g., rollover) and optimizing airbag deployment strategies. Thus, the function of a gyroscope is used.
2. **Laptop accidental free fall:** Many modern laptops have sensors to detect free fall and suddenly stop the hard drive head to prevent damage upon impact. While accelerometers are primary in detecting the acceleration due to gravity and the subsequent impact deceleration, gyroscopes can be used in conjunction to better characterize the motion (e.g., determining if the laptop is rotating during the fall), improving the accuracy and reliability of the free fall detection system. Thus, the function of a gyroscope can be used.
3. **Smartphone tilt for display rotation:** While the basic detection of static tilt relative to gravity is done by accelerometers, modern smartphones use gyroscopes in combination with accelerometers (IMU) for more accurate, stable, and responsive orientation sensing. The gyroscope measures angular velocity, allowing the phone to detect rotations quickly and smoothly, distinguish intentional rotations from accidental movements, and provide faster screen transitions between portrait and landscape modes. Thus, the function of a gyroscope is used.
IMUs provide six degrees of freedom (6-DOF) motion sensing (three axes of acceleration, three axes of angular velocity). This combined data allows for robust tracking of movement and orientation in 3D space, enabling these and many other features in various devices.