Sensors -Framework Overview

Sensors -Framework OverviewThe Sensors Framework consists of a sensor server and channel based -client APIs for supporting an extensible set of sensor hardware. The sensor -server defines a plug-in interface for adding sensor plug-ins for any type -of sensor hardware. The channel APIs enable client applications to interact -with the sensor hardware. -

Key Concepts -and Terms

Sensor Channel: The sensor channel forms a medium of interaction between the sensor -hardware and client applications.
The data from one physical sensor -can be mapped to several channels. For example, the Sensor System handling -an acceleration sensor can provide raw data on one channel and preprocessed -tap events on another.
Channel Properties: Channel properties contain properties of a specific channel, such as -data rate, availability, connection type and so on.
Data item: A data item is a discrete data package that contains sensor data or -an event parsed from sensor data and related values, such as timestamp. Each -channel provides a single type of data item only.
Channel condition: A value-operator pair targeting a single value inside a data item, -indicated by an index. A condition is met when the channel data value in comparison -with the condition value using condition operator is true. The conditions -are gathered in condition sets.
There are two condition types: single -limit conditions and range conditions. Range conditions are formed from two -separate conditions, representing the lower and upper limits of the range.
Channel Condition Set: A set of channel conditions. Following are the two types of condition -sets:
-
AND condition set: An AND condition is met only if a data value satisfies -all conditions in the set.
-
OR condition: An OR condition is met if a data value satisfies even -one single condition in the set.
-

Description

The -sensor server provides a plug-in interface (Sensor Definitions APIs) that -enables platform developers to create sensor plug-ins for required sensors -hardware. The sensor plug-ins enable the interaction between a client application -and the sensor hardware through sensor channels. The Sensor Channel APIs provides -access to each sensor channel.

One physical sensor can -provide several different types of data. For example, the physical magnetometer -can provide data for the Magnetometer channel and the Magnetic North channel. -Each sensor channel has its own sensor channel data definition in the Sensor -Definitions APIs that defines the format of the data package supplied by the -sensor channel. The data definition can also define properties for each data -item in the data package.

The sensor server facilitates the transfer -of data from one sensor hardware to multiple clients simultaneously. It also -resolves any contention between client applications for opening channels or -configuring a sensor device.

APIs - - - - -API -Description - - - - -CSensrvChannelFinder -The channel finder provides functions to search and find sensor channels -that are supported by the Symbian device. - - -CSensrvChannel -The sensor channel provides functions to open and control a sensor -channel. - - -CSensrvChannelCondition -The sensor channel provides functions for notifying when a specific -condition is met. - - - -CSensrvChannelConditionSet -The sensor channel condition set provides functions for adding one -or more channel conditions to a condition set. - - -MSensrvChannelListener -The sensor channel listener is a callback interface that tracks for -new channels installed on the Symbian device. - - -MSensrvChannelConditionListener -The sensor channel condition listener is a callback interface that -notifies the clients when a condition-set is satisfied. - - -MSensrvDataListener -The sensor data listener is a callback interface that notifies the -clients when the sensor data is available. - - -MSensrvPropertyListener -The sensor property listener is a callback interface that notifies -the client when a channel property changes. - - - -

- -

A physical sensor can supply data to several sensor channels (CSensrvChannel) -. A sensor channel provides data to an application in a channel-specific data -format (for example, TSensrvXyzData) through a callback to the MSensrvDataListener::DataReceived() interface. A -sensor channel has a single channel info item (TSensrvChannelInfo) that describes the channel in general. A sensor channel has multiple -property items (TSensrvProperty) -that describe the channel in more detail. Each property item is referenced -by a property id and an index.

Typical Uses

Using -the sensor channel APIs, you can perform the following operations:

List all the sensor channels that are available for a particular sensor -type. For details, see Querying -for Sensor Channels
Receive and control periodic sensor data.
For details, see Receiving Data from Sensors
Configure sensor channels.
For details, see Retrieving -Channel Properties and Setting -Channel Properties
Receive notifications about sensor channel additions and removal. For -details, see Receiving -Notifications about Channel Changes
Configure a sensor channel to support conditional listening. This means -that you can configure it to notify you when the data on the channel matches -some particular values, or exceeds specified boundaries. For details, see Receiving Channel Data based -on Conditions.

-Using Sensor -Channels APIs -Compensating -Sensor Data for Display Orientation + + + + + +Sensors +Framework OverviewThe Sensors Framework consists of a sensor server and channel based +client APIs for supporting an extensible set of sensor hardware. The sensor +server defines a plug-in interface for adding sensor plug-ins for any type +of sensor hardware. The channel APIs enable client applications to interact +with the sensor hardware. +

Key Concepts +and Terms

Sensor Channel: The sensor channel forms a medium of interaction between the sensor +hardware and client applications.
The data from one physical sensor +can be mapped to several channels. For example, the Sensor System handling +an acceleration sensor can provide raw data on one channel and preprocessed +tap events on another.
Channel Properties: Channel properties contain properties of a specific channel, such as +data rate, availability, connection type and so on.
Data item: A data item is a discrete data package that contains sensor data or +an event parsed from sensor data and related values, such as timestamp. Each +channel provides a single type of data item only.
Channel condition: A value-operator pair targeting a single value inside a data item, +indicated by an index. A condition is met when the channel data value in comparison +with the condition value using condition operator is true. The conditions +are gathered in condition sets.
There are two condition types: single +limit conditions and range conditions. Range conditions are formed from two +separate conditions, representing the lower and upper limits of the range.
Channel Condition Set: A set of channel conditions. Following are the two types of condition +sets:
+
AND condition set: An AND condition is met only if a data value satisfies +all conditions in the set.
+
OR condition: An OR condition is met if a data value satisfies even +one single condition in the set.
+

Description

The +sensor server provides a plug-in interface (Sensor Definitions APIs) that +enables platform developers to create sensor plug-ins for required sensors +hardware. The sensor plug-ins enable the interaction between a client application +and the sensor hardware through sensor channels. The Sensor Channel APIs provides +access to each sensor channel.

One physical sensor can +provide several different types of data. For example, the physical magnetometer +can provide data for the Magnetometer channel and the Magnetic North channel. +Each sensor channel has its own sensor channel data definition in the Sensor +Definitions APIs that defines the format of the data package supplied by the +sensor channel. The data definition can also define properties for each data +item in the data package.

The sensor server facilitates the transfer +of data from one sensor hardware to multiple clients simultaneously. It also +resolves any contention between client applications for opening channels or +configuring a sensor device.

APIs + + + + +API +Description + + + + +CSensrvChannelFinder +The channel finder provides functions to search and find sensor channels +that are supported by the Symbian device. + + +CSensrvChannel +The sensor channel provides functions to open and control a sensor +channel. + + +CSensrvChannelCondition +The sensor channel provides functions for notifying when a specific +condition is met. + + + +CSensrvChannelConditionSet +The sensor channel condition set provides functions for adding one +or more channel conditions to a condition set. + + +MSensrvChannelListener +The sensor channel listener is a callback interface that tracks for +new channels installed on the Symbian device. + + +MSensrvChannelConditionListener +The sensor channel condition listener is a callback interface that +notifies the clients when a condition-set is satisfied. + + +MSensrvDataListener +The sensor data listener is a callback interface that notifies the +clients when the sensor data is available. + + +MSensrvPropertyListener +The sensor property listener is a callback interface that notifies +the client when a channel property changes. + + + +

+ +

A physical sensor can supply data to several sensor channels (CSensrvChannel) +. A sensor channel provides data to an application in a channel-specific data +format (for example, TSensrvXyzData) through a callback to the MSensrvDataListener::DataReceived() interface. A +sensor channel has a single channel info item (TSensrvChannelInfo) that describes the channel in general. A sensor channel has multiple +property items (TSensrvProperty) +that describe the channel in more detail. Each property item is referenced +by a property id and an index.

Typical Uses

Using +the sensor channel APIs, you can perform the following operations:

List all the sensor channels that are available for a particular sensor +type. For details, see Querying +for Sensor Channels
Receive and control periodic sensor data.
For details, see Receiving Data from Sensors
Configure sensor channels.
For details, see Retrieving +Channel Properties and Setting +Channel Properties
Receive notifications about sensor channel additions and removal. For +details, see Receiving +Notifications about Channel Changes
Configure a sensor channel to support conditional listening. This means +that you can configure it to notify you when the data on the channel matches +some particular values, or exceeds specified boundaries. For details, see Receiving Channel Data based +on Conditions.

+Using Sensor +Channels APIs +Compensating +Sensor Data for Display Orientation

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