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     7     Nokia Corporation - initial contribution.

     8 Contributors: 

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    10 <!DOCTYPE task

    11   PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd">

    12 <task id="GUID-4B709839-8EEF-4AD2-9868-9AF0176B1E5B" xml:lang="en"><title>Using

    13 Sensor Channels APIs</title><shortdesc>The Sensor Channel establishes a data exchange connection between

    14 the sensor framework and hardware using the sensor channel APIs.</shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

    15 <steps id="GUID-4DD07DEC-6017-4237-BE46-1D69E5FBD744-GENID-1-7-1-8-1-1-8-1-4-1-5-1-3-1">

    16 <step id="GUID-9A69E5AD-E938-4092-A8C2-CB65C37C8962-GENID-1-7-1-8-1-1-8-1-4-1-5-1-3-1-1"><cmd>Include the library <b>SensrvClient.lib</b> in

    17 your <b>.mmp</b> file.</cmd>

    18 </step>

    19 <step id="GUID-4F637EBD-BD56-44FA-A984-E93CC4B2B3B6"><cmd>Include the following

    20 header files, as they are required for accessing sensor channels regardless

    21 of the channel type: </cmd>

    22 <info><ul>

    23 <li><p>sensrvchannel.h</p></li>

    24 <li><p>sensrvchannelinfo.h</p></li>

    25 <li><p>sensrvtypes.h</p></li>

    26 <li><p>sensrvchannelfinder.h</p></li>

    27 <li><p>sensrvdatalistener.h</p></li>

    28 </ul><p>In addition to these, include the

    29 necessary header files based on the type of channel to be used. For information

    30 about channel-specific header files, see <xref href="GUID-F1935106-C730-4C64-A19A-0FC04F0E7121.dita">Types

    31 of Sensor Channels</xref>.</p></info>

    32 </step>

    33 <step id="GUID-F5BC52B6-67DD-4F59-889B-C5DE4C69029B"><cmd>Retrieve details

    34 about the required sensor channel. For details. see <xref href="GUID-44FDDA27-1A5D-42B5-8DE0-D9E88EB75C93.dita">Querying

    35 for Sensor Channels</xref>.</cmd>

    36 </step>

    37 <step id="GUID-FBBD3A8B-F240-4DC0-B516-3A51FDD86A88"><cmd>Connect to the sensor

    38 by opening a connection with the sensor channel.</cmd>

    39 <substeps id="GUID-C9E5B9FC-C637-4DEB-AAAF-E38C6CD9A18A">

    40 <substep id="GUID-CA2CFF9C-3168-4060-AC39-8CB6FBA4BCA2"><cmd>Create an instance

    41 of <codeph>CSensrvChannel</codeph> and specify the instance of <codeph>TSensrvChannelInfo</codeph> returned

    42 by <xref href="GUID-5F108D03-C8A6-3EF9-B103-2E8916633602.dita#GUID-5F108D03-C8A6-3EF9-B103-2E8916633602/GUID-E58BAF1B-57AA-3E85-A4F9-8C6C29043FBD"><apiname>CSensrvChannelFinder::FindChannelsL()</apiname></xref>, as a parameter

    43 in the <codeph>NewL()</codeph> constructor.</cmd>

    44 <stepxmp><codeblock xml:space="preserve"> CSensrvChannel* sensorChannel;

    45  sensorChannel = CSensrvChannel::NewL(channelInfoList[0]);// channelInfoList is

    46 //   returned by the CSensrvChannelFinder::FindChannelsL()funtion</codeblock></stepxmp>

    47 </substep>

    48 <substep id="GUID-30E6033F-E316-4BDB-AF22-2369463DF709"><cmd>Open the sensor

    49 channel using <xref href="GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844.dita#GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844/GUID-277A4940-2E5E-3E8E-AB61-552CD2375F3C"><apiname>CSensrvChannel::OpenChannelL()</apiname></xref> function.</cmd>

    50 <stepxmp><codeblock xml:space="preserve">channel-&gt;OpenChannelL();</codeblock></stepxmp>

    51 </substep>

    52 </substeps>

    53 </step>

    54 <step id="GUID-7A414271-040C-4107-B047-9416747C66A6"><cmd>Perform any of the

    55 following operations:</cmd>

    56 <info><ul>

    57 <li><xref href="GUID-BA0D9DA9-3B54-4964-A4D6-9ADA4DEB7231.dita">Receive data from

    58 sensors</xref></li>

    59 <li><xref href="GUID-09E44FE5-6BEE-49FF-8BBF-CBB3C066EE10.dita">Listen for channel

    60 changes</xref></li>

    61 <li><xref href="GUID-83630B57-D842-4B60-8AF0-D2965251DE29.dita">Retrieve channel

    62 properties</xref></li>

    63 <li><xref href="GUID-0CA7F22E-59D7-4D65-9D6C-735E4E0F0454.dita">Set channel properties</xref></li>

    64 <li><xref href="GUID-E93EE459-8CF4-42A1-B06C-E78E56FD25A0.dita">Listen for channel

    65 property changes</xref></li>

    66 <li><xref href="GUID-60EE22AA-402D-4FC2-9AD1-B3AEF822E8DC.dita">Receive channel

    67 data based on conditions</xref></li>

    68 </ul></info>

    69 </step>

    70 <step id="GUID-61840C55-476C-4DC3-A946-A440330B9DE5"><cmd>Close the channel.</cmd>

    71 <info><codeblock xml:space="preserve">channel-&gt;CloseChannel();</codeblock><note type="important"> A

    72 channel must be closed when not required, as it reduces power consumption

    73 of the Symbian device. An open sensor channel keeps the device processor active

    74 each time data arrives. Therefore, the processor does not change to idle state

    75 even when the device user is not performing any operations on the device.</note></info>

    76 </step>

    77 </steps>

    78 </taskbody></task>