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 how many of the above actions is the function of the accelerometer required?

(a) Only one

(b) Only two

(c) All three

(d) None

4. Ans: c

Explanation:

An accelerometer is a device that measures acceleration forces, such as gravity and motion, by converting them into electrical signals. 

An accelerometer works by utilizing an electromechanical sensor that is designed to measure either static or dynamic acceleration. 

Static acceleration is the constant force acting on a body, like gravity or friction. These forces are predictable and uniform to a large extent. For example, the acceleration due to gravity is constant at 9.8 m/s – and the gravitation force is almost the same at every point on Earth.

Dynamic acceleration forces are non-uniform, and the best example is vibration or shock. A car crash is an excellent example of dynamic acceleration 

When an accelerometer detects a sudden change in a car’s speed, signaling an imminent collision, it triggers an electrical circuit that makes the airbags inflate.

Hence, statement 1 is correct.

In a laptop, the accelerometer senses freefall and parks the hard drive—usually—before the device hits the ground.

Hence, statement 2 is correct.

Accelerometer in  cellphone, MP3 player, or handheld games console, sense when you tilt it from side to side. That’s how a cellphone automatically figures out when to switch the screen layout from portrait to landscape. 

Hence, statement 3 is correct.

Accelerometer  in Rockets measure changes in rocket speed ,apogee (when a craft is at its maximum distance from Earth or another mass, so its acceleration due to gravity is at a minimum) and orientation (because tilting something changes the way gravity acts on it and the force it feels). 

Accelerometers are also widely used in inertial navigation and guidance systems in such things as airplane and ship autopilots. 

Applications of Accelerometer

Accelerometers are versatile sensors used in various sectors to measure acceleration and orientation. Key applications include:

• Consumer Electronics: Integrated into smartphones and wearables for screen orientation, step tracking, and gaming.
• Automotive: Essential for vehicle dynamics, airbag deployment, and anti-theft systems.
• Aerospace and Aviation: Used in navigation systems and aircraft performance monitoring.
• Industrial: Employed for vibration analysis, enabling predictive maintenance.
• Healthcare: Assist in patient monitoring and rehabilitation by tracking body movement.
• Building Monitoring: Detect vibrations in structures to assess stability and seismic activity.

Read: Solved PYQs Science & Technology With Explanation 2023 UPSC Prelims