Wireless/software Trigger

The Wireless/software trigger settings contain all the settings for triggering the Qualisys system using a wireless trigger, the keyboard or RT client applications. Possible input:

  • Qualisys wireless trigger
    Use the Trig button for starting and/or stopping captures and use the Event button for creating events

  • Keyboard
    Use space for starting captures. The space key cannot be used for stopping captures or creating events. In addition, the PageDown key can be used for starting and stopping measurements, and the PageUp key for settings events.

    Alternatively, the keyboard shortcut Ctrl+M can be used for stopping an ongoing capture (independent of wireless trigger settings).

  • RT Client application
    For example mobile apps and plugins for Matlab and Labview.

  • UDP start or stop packet
    Start or stop a capture when receiving an UDP start/stop packet, see chapter UDP start/stop.

The wireless trigger or keyboard cannot be used to trigger external equipment (e.g. EMG devices). Simultaneous triggering of the camera system and external devices require the use of an external trigger connected to a trigger port.

The following settings are available:

  • Function
    Select the wireless trigger function from the drop-down list.

    • Start and stop capture disabled
      The Wireless trigger or keyboard is not used for starting or stopping captures.

    • Start capture
      The start of a capture is delayed until a trigger event is received.

    • Stop capture
      An incoming trigger event will stop the capture.

    • Start and stop capture
      Both the start and stop of the capture is controlled by the trigger event.

  • Notes on trigger function:

    • The trigger settings of the Wireless trigger and the trigger ports are complementary, e.g., when the function of multiple trigger ports and the wireless trigger is set to Start capture, any of these trigger events will start a capture.

    • When choosing Stop capture or Start and stop capture the capture will also stop if the end of measurement time is reached, unless you are have checked the Continuous capture option in the Start capture dialog.

    • The stopping behavior of RT client applications may deviate from the Function setting.

  • Start/stop on UDP packet
    Select the whether to listen for UDP start/stop packets

    • Listener disabled
      Disable the start and stop on UDP packets.

    • Listener enabled
      Enable starting or stopping a capture when receiving an UDP start/stop packet.

    • Listen for Main QTM instance
      Enable start on the camera start time UDP packet. When using this setting QTM does not start or stop when receiving the UDP start/stop packet. Use this setting for Agent systems in a multiple video system setup.

  • Event color
    Color associated with this type of event. Click in the value field to pick a color.

  • Event text
    Text label associated with this type of event. Click in the value field to edit.

UDP start/stop

QTM supports starting and stopping captures via a UDP start/stop protocol. QTM also broadcasts UDP start and stop messages for every capture that can be used to start and stop captures on external devices that support the UDP start/stop protocol.

To enable external devices to control captures in QTM via UDP start/stop, follow these steps:

  1. Make sure the computer running QTM and the controlling device are on the same local area network.

  2. Make sure that the QTM and the controlling device use the same port for UDP communication. In QTM the Capture Broadcast Port can be set on the Real-Time output page under the Project Options.

  3. In the Wireless/Software trigger settings, set Function to the desired action, for example Start and Stop capture if you want to start and stop the capture using UDP start and stop.

  4. Enable the Start/Stop on UDP packet option.

The next time you start a capture, QTM will wait for a trigger or stop the capture depending on the chosen trigger function. If you want QTM to do an automatic series of captures controlled via UDP start/stop, make sure the Batch capture option is checked in the Start Capture dialog.

The UDP start/stop packets sent by QTM have the following XML format.

  • XML start packet:

  • Copy 
    <?xml version="1.0" encoding="UTF-8" standalone="no"?>
       <CaptureStart>
          <Name VALUE="measurement name"/>
          <DatabasePath VALUE="measurement directory"/>
          <Delay VALUE="0"/>
          <PacketID VALUE="increasing number"/>
          <HostName VALUE="computer name"/>
          <ProcessID VALUE="process id (to be able to easier ignore own udp broadcast messages"/>
          <Notes VALUE=""/>
          <Description VALUE=""/>
          <Timecode VALUE=""/>
       </CaptureStart>

  • XML stop packet:

  • Copy 
    <?xml version="1.0" encoding="UTF-8" standalone="no"?>
       <CaptureStop RESULT="SUCCESS/FAIL/CANCEL">
          <Name VALUE="measurement name"/>
          <DatabasePath VALUE="measurement directory"/>
          <Delay VALUE="0"/>
          <PacketID VALUE="increasing number"/>
          <HostName VALUE="computer name"/>
          <ProcessID VALUE="process id (to be able to easier ignore own udp broadcast messages"/>
       </CaptureStop>

UDP packet parameters

QTM sends start packet

  • Name
    Filename without the .qtm ending

  • DatabasePath
    Name of the folder if automatic saving is enabled in the Start capture dialog

  • Delay
    Not in use

  • PacketID
    Unique ID

  • HostName
    Computer name

  • ProcessID
    PID for QTM process

  • Notes, Description, Timecode
    Not in use

QTM sends stop packet

  • RESULT

    • SUCCESS
      The capture is ended without any issues

    • FAIL
      The capture ended with an error

    • CANCEL
      The capture has been canceled

  • Name
    Filename without the .qtm ending

  • DatabasePath
    Name of the folder if automatic saving is enabled in the Start capture dialog

  • Delay
    Not in use

  • PacketID
    Unique ID

  • HostName
    Computer name

  • ProcessID
    PID for QTM process

QTM receives start packet

  • Name
    Sets the QTM file name used for the capture

  • HostName
    Used in combination with ProcessID to ignore messages from the local QTM

  • ProcessID
    Used in combination with HostName to ignore messages from the local QTM

  • DatabasePath, Delay, PacketID, Notes, Description, Timecode
    Not in use

QTM receives stop packet

  • Name
    Sets the QTM file name used for the capture

  • HostName
    Used in combination with ProcessID to ignore messages from the local QTM

  • ProcessID
    Used in combination with HostName to ignore messages from the local QTM

  • RESULT, DatabasePath, Delay, PacketID
    Not in use