USER MANUAL
STM 550B / EMSIB - EASYFIT MULTISENSOR FOR IOT APPLICATIONS (2.4 GHZ BLE)
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F-710-017, V1.0
STM 550B / EMSIB User Manual | v1.3 | June 2020 | Page 24 / 115
3.5
Acceleration sensor
STM 550B integrates an acceleration sensor which enables two key use cases:
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Measuring device orientation relative to the earth gravity vector
This allows determining the direction into which STM 550x is oriented relative to the
earth gravity vector. See chapter 11.2 for an example.
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Measuring device acceleration by external force
This enables detecting cases where the device is moved or shaken
The second case (acceleration vector change) can be used to determine the presence or
absence of small vibrations (acceleration vector changes). Examples use cases causing such
small vibrations include asset utilization (e.g. a motor to which STM 550x is attached is run-
ning) or asset movement (e.g. an asset to which STM 550x is attached changes its location).
If such change in acceleration is above a certain threshold then this will be reported as part
of the regular data telegram. If the acceleration exceeds this threshold for the first time,
then this will be reported immediately (wake-on-acceleration).
Figure 11 below shows the orientation of the acceleration vector relative to STM 550B.
Figure 11
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Acceleration sensor orientation