Sensor Channels APIs
The Sensor Channel establishes a data exchange connection between
the sensor framework and hardware using the sensor channel APIs.
Include the library
Include the following
header files, as they are required for accessing sensor channels regardless
of the channel type:
about the required sensor channel. For details. see
for Sensor Channels
Connect to the sensor
by opening a connection with the sensor channel.
Create an instance
and specify the instance of
, as a parameter
sensorChannel = CSensrvChannel::NewL(channelInfoList);// channelInfoList is
// returned by the CSensrvChannelFinder::FindChannelsL()funtion
Open the sensor
Perform any of the
Close the channel.
channel must be closed when not required, as it reduces power consumption
of the Symbian device. An open sensor channel keeps the device processor active
each time data arrives. Therefore, the processor does not change to idle state
even when the device user is not performing any operations on the device.
Querying for Sensor Channels
You can retrieve a list of sensor channels that are available for a particular sensor type. Once you get the list of sensor channels that are active, you can perform any required operations such as configuring sensor channel properties, controlling sensor channels and so on.
Receiving Data from Sensors
You can implement a data listener to receive data from the sensors. Based on the data received, you can perform specific actions on the Symbian device. For example, if you receive information from the sensor about the distance between the device and the user then based on this information, you can disable or enable the loudspeaker mode on the Symbian device.
Retrieving Channel Properties
A sensor channel is associated with properties such as channel availability status, data transmission rate, data format and so on. Also, each field in the data type supplied by a sensor channel can have its own properties. The channel properties can be retrieved using the
Setting Channel Properties
The channel properties can be configured using the
Listening for Property Changes
The sensor channel APIs enable the client applications to be notified about the changes to properties associated with a sensor channel.
Listening for Channel Changes
The sensor channel APIs enable you to receive notifications when a sensor channel is added or removed. This ensures that you are informed of changes to sensor channels whenever there is a change. For example, you can receive notifications when a specific proximity sensor channel is added.
Receiving Channel Data based on Conditions
Conditional listening enables you to receive sensor data feeds based on a specific condition. For example, you can choose to receive sensor feeds that are only movement specific.
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