Measuring Acceleration with an Accelerometer

Acceleration is a change in velocity with respect to time. Accelerometers are transducers that represent acceleration as a voltage. They are specified by the range, frequency response, and the sensitivity of the device.

Accelerometers come in two axial types. The most common accelerometer measures acceleration along only a single axis. The second type is a tri-axial accelerometer, which can create a 3D vector of acceleration.

Both types of accelerometer can be either passive or active sensors. Both types also come with either both leads insulated from the case (isolated) or with one lead grounded to the case. To measure acceleration with a passive sensor, the sensor must be connected to a charge-sensitive amplifier.

The active accelerometer is nearly identical to the passive accelerometer, with the addition of a charge-sensitive amplifier built inside the accelerometer. The current source provides the excitation for the built-in amplifier of the sensor, while the instrumentation amplifier measures the voltage potential across the leads of the sensor.

Some analog input devices support programmable AC or DC coupling. If your device supports this feature, your acceleration measurement task is created using AC coupling. If you desire a different coupling behavior, you can change this property programmatically.