We all play games on our smartphones where you need to use landscape mode or some apps which need portrait mode, our phones automatically change to the need. Why does it happen? Or what causes it to happen? Well to answer that question, an accelerometer comes into the picture. The primary function of the accelerometer in mobile phones is to modify the orientation of the device from horizontal to vertical and vice versa.

Read on, to study more about the types, working principle, uses of accelerometer along with how it differs from a gyroscope in common forces of mechanics.

Accelerometer

An electromechanical instrument for measuring acceleration forces is called the accelerometer. These forces could be stationary, like the constant pull of gravity, or dynamic, like in the case of many mobile gadgets, to detect motion or vibrations.

Fundamentally speaking, acceleration is the change in velocity over a predetermined period of time. If we know the distance traveled and the time required, we may calculate the speed of a given body.

However, the force enters the picture when calculating acceleration. Recently, a wide range of uses for accelerometers has emerged. Mobile phones also have accelerometers thanks to the use of microelectronic and mechanical technologies.

Accelerometer Diagram

The below circuit diagram depicts the popular accelerometer in usage- ADXL335

Accelerometer Working Principle

An accelerometer’s main functional requirement is that it converts mechanical energy into electrical energy. When a mass that is actually like a spring is placed on the sensor, it starts to descend at that point. It has an acceleration since it is descending. This acceleration then transforms into a measurement of the electric signal, which is used to calculate the range in the position of the device. Both the simple structures and the programmed structural gadgets can both be found with an accelerometer. It comes in both analog and digital forms.

Even while it appears to be a simple circuit for a bigger electronic device, it actually has many distinct sorts of parts, each of which has its own functions and operates in a variety of ways. The two most popular words would be the capacitance sensor in capacitors and the piezoelectric effect. The most prevalent type, known as the piezoelectric effect, uses microscopic crystal structures that are stressed by acceleration forces. These internal stresses cause the crystals to produce voltages, which are then interpreted by an accelerometer to measure the motion’s velocity and orientation.

Learn about conservation of mechanical energy.

Types of Accelerometer

Both digital and analog acceleration sensors are offered. Different techniques are used to design accelerometers. The mechanical motion produced by an accelerometer is often converted into an electrical signal using piezoelectric, piezoresistive, and capacitive components.

Piezoresistive Accelerometer

Piezoresistive accelerometers are made for measuring high-frequency, high g-shocks. A piezoresistive accelerometer uses the change in resistance of piezoresistive materials to convert mechanical strain to a DC output voltage rather than monitoring capacitance changes in the seismic mass in supercapacitors. The majority of piezoresistive designs are either of the MEMS (gas-damped) or bonded strain gauge (fluid-damped) types, and they are appropriate for impacting measurements wherein frequency range and g level are quite high.

Piezoresistive accelerometers are frequently employed in weapon testing, seismic measurements, and testing of anti-lock brake systems, safety airbags, and traction control systems in automobiles.

Piezoelectric Accelerometer

A piezoelectric accelerometer generates its own power, eliminating the requirement for an external power source. Additionally, its acceleration proportional output may be combined to produce velocity and displacement proportional signals, and it has no moving parts to wear out. They can operate in extremely hot or cold conditions, but because of their high output impedance, they need charge amplifiers and low-noise connections to condition the signal.

The piezoelectric material slice, often a ferroelectric ceramic that has been artificially polarized, is what gives piezoelectric accelerometers their distinctive piezoelectric effect. It produces an electrical charge across its pole faces in response to mechanical stress, whether it be in tension, compression, or shear, and this charge is proportional to the applied force.

Capacitive MEMS Accelerometer

Micro-Electro-Mechanical-System is referred to as MEMS. MEMS is a fabrication technology or creative innovation. Instead of a modification in blockage, this type of accelerometer distinguishes changes in capacitance. This MEMS accelerometer is present in most mobile phones.

The capacitance accelerometer, detects changes in capacitance between nearby microstructures. If an accelerated force moves any one of these structures, the capacitance will change, causing the accelerometer to convert the capacitance to voltage for interpretation.

In performance-driven applications, MEMS accelerometers with capacitive bases offer precise vibration detection. Performance of MEMS capacitive accelerometers has advanced significantly, and ADI’s range tops the market in terms of power, noise, bandwidth, and temperature parameters. With capabilities like self-test, peak acceleration, and spectral warnings, MEMS capacitive accelerometers provide high levels of integration and functionality.

Accelerometer vs Gyroscope

The differences between an accelerometer and gyroscope are mentioned below.

Parameters	Accelerometer	Gyroscope
Meaning	An instrument used to measure acceleration is the accelerometer.	A tool for measuring orientation is a gyroscope.
How it works	It is an electromechanical device.	They operate according to the angular momentum theory.
Parts	The internal moveable assembly, the mass, the spring, and the fixed assembly.	Gyroscope frame, gimbal, spin axis, and rotor.
Signal to noise ratio	Lower	Higher
Measurement of angular velocity	It cannot be used.	It can be used.

Uses of Accelerometer

The common uses of accelerometer are:

• Accelerometers that have a high sensitivity are utilized in inertial navigation systems.
• To recognise and keep an eye on rotating machinery vibrations.
• To have photographs shown on digital camera screens in an upright orientation.
• For drone flight stabilization.
• Accelerometers are used to measure acceleration, shock, vibration, and orientation.
• Used by laptops and mobile devices to determine the device’s location.
• Biaxial and triaxial acceleration at high frequencies are recorded in biological applications to distinguish between animal behavioral patterns.
• Checking the health of the equipment.
• To find rotator machine issues.
• These are also employed in structural and building monitoring to track the movement and vibration of the building under dynamic loads.
• To evaluate the depth of chest compressions during CPR.
• Accelerometer sensors are used by navigation systems to determine direction.

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