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How to Select an Accelerometer

An accelerometer triggers the airbag in your car. Another protects your disc drive should you drop your computer. Still another orients your screen to match the way you̵7;re holding your camera. There are dozens, perhaps even hundreds, of other applications. As you̵7;re selecting an accelerometer for your task, there are some elements you need to consider.

Instructions

- 1
  Match the output type of your accelerometer to the input type of your processing circuit. The primary choice is to go with a digital or analog output.
- 2
  Choose the number of axes your application needs. An accelerometer for your model train could need to measure the horizontal acceleration in x and y, but it̵7;s unlikely to need to measure in the z-axis, off the tracks.
- 3
  Fit the measurement range of the device to the range you expect in your application. For example, an orientation sensor only needs to cover the range of +/- 1g -- that is, +/- the acceleration due to Earth̵7;s gravity at the surface. A shock and vibration sensor could need to measure tens or hundreds of ̶0;gees.̶1;
- 4
  Calculate the update rate you need and match the frequency response of the accelerometer to the update rate. For example, if you need to take a measurement every quarter of a second, you need a frequency response that̵7;s at least 1 / (1/4 sec) = 4 Hertz.
- 5
  Measure the mass of the system you̵7;re planning on monitoring and choose an accelerometer that is less than one-tenth the mass of the system. If the accelerometer is a larger percentage of the total mass, it influences the motion rather than simply providing a measurement.

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