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9150-0125-01 R-1
9.1.16 ACCELEROMETER MODULE
The accelerometer can detect acceleration changes independent from orientation changes. Either or both of these changes
can be enabled to generate a motion event.
9.1.16.1 Motion/Vibration/In-Motion Events
Additionally, it is possible to require consistent motion for a period of time before declaring the device is "In-Motion". This is
accomplished with the vibration continuous time setting. When this setting is non-zero, successive motion events are used to
meet the continuous vibration setting requirement.
Likewise, it is possible to require consistent no-motion to occur to transition out of the "In-Motion" state, which is
accomplished with the vibration lacking continuous time seconds setting.
9.1.16.2 External Accelerometer
It is possible to use an external accelerometer and set instantaneous motion via the set motion API. This API can be used if the
accelerometer mode is set to the manual state. In this state, the internal accelerometer will be placed in a low power state.
Reading motion via the get motion API does not return instantaneous motion as the set command does, but rather the "In-
Motion" state of the device. Thus, in order for the get motion command to return a non-zero value, the set motion API must
be called repetitively, once every two seconds at a minimum, until the continuous vibration requirement is met. Only after
that condition is met, will the get motion API return a non-zero value.
9.1.16.3 Accelerometer Sensitivity
The accelerometer can use a 2G, 4G, or 16G scale reference for acceleration detection, in addition to a sensitivity setting,
1-10, which is proportional to that scale. So, a 2G scale with a 1 sensitivity will yield the most sensitive motion detection
possible, whereas a 16G scale with a 10 sensitivity will yield the least sensitive setting.
Changes to accelerometer sensitivity occur in real-time, and events can be used to enable URC messages to quickly test the
results of sensitivity changes.
9.1.16.4 Orientation Detection
6D orientation match detection can be specified such that transitions in or out of configurable orientation states can be identified.
9.1.16.5 Input and OTA Events
Accelerometer events can be mapped to Software Input functions (See Inputs Module Section). Events that support active
and inactive states can be mapped to count, accumulate, transition, and undesired state functions. Events that do not
support open and closed states, such as a motion event, can be mapped to count and transition functions.
Mod Msg Input Config 1-8 OTA messages make it possible to describe accelerometer events and states through OTA
messages.
9.1.17 POWER MANAGEMENT
Power management supports 3 power states as follows:
9.1.17.1 Normal Operation
In Normal Operation, tracking occurs at the at rest and in-motion tracking intervals.
9.1.17.2 Partial Suspended
In the Partial Suspended state, tracking occurs at the low battery update interval, if the low battery update interval is less
than the normal or in-motion interval respective of the current tracking state.
ST150M User Manual
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