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author | Etienne Le Grand <etn@google.com> | 2013-03-05 22:00:33 -0800 |
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committer | Etienne Le Grand <etn@google.com> | 2013-03-06 17:14:58 -0800 |
commit | 1461f28f503d75c6eda29ec9bbd5db33b44f65fe (patch) | |
tree | 3e226ec38cbf8f0b74e1ecf4ae29f79535af8910 /include/hardware/sensors.h | |
parent | ca8581433b778c60b074839baa6c3f2233c09614 (diff) | |
download | hardware_libhardware-1461f28f503d75c6eda29ec9bbd5db33b44f65fe.zip hardware_libhardware-1461f28f503d75c6eda29ec9bbd5db33b44f65fe.tar.gz hardware_libhardware-1461f28f503d75c6eda29ec9bbd5db33b44f65fe.tar.bz2 |
Add significant motion description
Change-Id: I56de3f2c12243b3d25cd825b66f7685e674533ff
Diffstat (limited to 'include/hardware/sensors.h')
-rw-r--r-- | include/hardware/sensors.h | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/include/hardware/sensors.h b/include/hardware/sensors.h index d6b02c6..18b682d 100644 --- a/include/hardware/sensors.h +++ b/include/hardware/sensors.h @@ -546,10 +546,23 @@ enum { * is detected and automatically disables itself. * The only allowed value to return is 1.0. * - * - * TODO: give more details about what constitute significant motion - * and/or what algorithm is to be used - * + * A significant motion is a motion that might lead to a change in the user + * location. + * Examples of such motions are: + * walking, biking, sitting in a moving car, coach or train. + * Examples of situations that should not trigger significant motion: + * - phone in pocket and person is not moving + * - phone is on a table, even if the table shakes a bit due to nearby traffic + * or washing machine + * + * A note on false positive / false negative / power consumption tradeoff + * - The goal of this sensor is to save power. + * - Triggering an event when the user is not moving (false positive) is costly + * in terms of power, so it should be avoided. + * - Not triggering an event when the user is moving (false negative) is + * - acceptable as long as it is not done repeatedly. If the user has been + * walking for 10 seconds, not triggering an event within those 10 seconds + * is not acceptable. * * IMPORTANT NOTE: this sensor type is very different from other types * in that it must work when the screen is off without the need of |