Accelerometer

What is an accelerometer?

An accelerometer – often also referred to as accelerometer sensor or acceleration sensor – is a measuring device that captures the acceleration of an object. Acceleration is a dynamic load caused by gravitation, vibration, or human actions. Accelerometers can be used in a variety of ways and applications, e.g. for vibration measurements. Today, most smartphones contain accelerometer sensors, for instance for display orientation recognition.

How does an accelerometer work?

Accelerometers contain a proof mass (also called seismic mass) which is mechanically damped, e.g. with a spring. In case an acceleration occurs, the proof mass changes its position relative to the sensor housing. Modern accelerometer sensors are often designed as electromechanical systems, where the dynamic load is captured by an electronic circuit (see also MEMS accelerometers).

What is a piezoelectric accelerometer?

Piezoelectric accelerometers use the piezoelectric effect to capture highly dynamic loads with great precision. Here, the seismic mass is attached to a piezoelectric crystal which generates an electric charge when a mechanical load is exerted on it. Piezoelectric accelerometers offer unique features such as miniature design including low weight, high frequency response, high temperature stability, and more. A typical application of a piezoelectric accelerometer is vibration measurement, which is a key requirement in a variety of industries and sectors.

What is an IEPE accelerometer?

IEPE stands for “Integrated Electronics Piezo-Electric” and refers to a specific type of piezoelectric accelerometer. In fact, most of today’s piezoelectric accelerometer sensors are IEPE accelerometers. Here, the electric charge produced by the sensing element is converted to a voltage signal in the accelerometer already, which facilitates signal transmission. Read more about the IEPE principle below.

What is an accelerometer calibrator?

As all precision sensors, accelerometers must be calibrated to ensure that they measure as accurately as possible. In the field, this is often done with a device called accelerometer calibrator, also referred to as vibration exciter or simply “shaker”. These shakers can provide a controlled vibration level in order to verify the sensitivity of accelerometer sensors and accelerometer-based measuring systems. Accelerometer calibrators are available as battery-powered systems and with constant or selectable amplitudes and frequencies.

What can be done with an accelerometer?

Accelerometers are very common in a variety of applications such as shock and vibration measurement, dynamic testing, modal analysis and many more. Regarding sectors, aerospace, automotive, consumer electronics and industrial manufacturing are leading the way, among others. In the last decades, accelerometer sensors have been more and more applied in medical and biological applications as well. Another key application area of accelerometers is condition monitoring: e.g., of buildings and bridges, where it is also called Structural Health Monitoring.

Which accelerometer types and technologies should you know?

There is a great variety of accelerometers out there, with measuring ranges up to 100,000 g and beyond. An important feature is the number of axes: A standard single-axis accelerometer sensor measures acceleration in one axis, while a triaxial accelerometer captures all dynamic loads in all three space axes.

Regarding technologies, aside from piezoelectric accelerometers there are also piezoresistive accelerometers and capacitive ones. Piezoresistive accelerometers are especially useful for high amplitudes of acceleration, as in shock measurement (>10,000 g) for example. Capacitive accelerometers can be built very compact as MEMS, measuring the change in capacitance caused by a dynamic load. They are beneficial in measuring low frequencies (static or quasi-static accelerations) for example.