To enable you to capture data from Vicon IMUs (Inertial Measurement Units) and optical markers simultaneously, you can use IMUs as digital devices in Nexus to stream and capture data. You can use IMUs to preview data in real time and to capture data onto the IMU's internal memory. You can then plug the IMUs into your PC via USB and use Nexus to download the captured data.
Before you begin using IMUs with Nexus, note the following points:
- Windows 10 and above only is supported. Ensure the latest Windows 10 updates are installed.
- To use Vicon IMUs in Nexus, first plug the supplied Bluetooth® (BLE) dongle into the relevant Windows PC. Ensure that its drivers have been updated: you can do this using the Windows Device Manager.
- To enable further setup and control of your IMUs after they are paired and recognized by Windows 10, you can download IMU Lightning desktop software. IMU Lightning enables you to see the status of IMUs outside of Nexus and is useful in certain troubleshooting situations.
- IMUs have five collection modes: 100 Hz (9-axis), 250 Hz (6-axis), 500 Hz (6-axis), 500 Hz (9-axis), or 1000 Hz (3-axis). To accommodate the IMUs, ensure that your Vicon system is running at a compatible frame rate.
- Nexus supports the use of up to four current Vicon IMUs.
- You can transfer the data that is collected and stored on your IMUs onto your PC using the IMU Transfer pane in Nexus (see Transfer data from IMUs).
To enable transfers to work, ensure you have downloaded and installed the.
Set up IMUs for capture
The following are brief notes on working with IMUs with Nexus. For more information on setting up and using IMUs to stream and capture data, see the IMeasureU documentation.
- If necessary (see previous points), download and install IMU Lightning.
- Ensure that the Bluetooth® dongle is plugged into the PC and that its drivers are up-to-date.
Turn on the IMUs and pair them to the relevant Windows computer, via Bluetooth settings in Windows 10.
- In Nexus, add the IMUs as digital devices and in the Properties pane, specify the required settings:
- In the System Resources pane, expand the Local Vicon System node, then right-click the Devices node, point to Add Digital Device and click Add IMeasureU Sensor.
In the Properties pane below, specify a Name and Sensor Number:
Property Description Name The identifier that you want to give to the IMU. Sensor Number The unique serial number of the device, which is found on the tag on the side of the IMU. Although you enter only the digits on the tag, this is an eight-digit number that is padded with four zeros when displayed in the Log.
For more information on the available properties, see IMeasureU Sensor node.
Note that if the connection to the IMU is lost (the device is displayed as gray in the System Resources pane), you can click the Sensor Reconnect button to reconnect. This button is not available while you are capturing a trial.
- If necessary, change the collection mode (frequency) at which the IMUs are to run.
To do this:
- In the Resources list, ensure the IMUs are selected.
- To display the axes for the IMUs, in the view pane, select Graph view.
- In the Properties pane, from the Mode list, select the required frequency.
- In the Graph view, the graphs change to reflect the selection.
If you need to calibrate the IMUs (normally only necessary when you update the camera firmware or if an offset occurs), see Calibrate IMUs. Note that, for calibration, you must set the collection mode to 100 Hz.
Attach the IMUs to the subject.
Set up and start capture in the usual way (see Capture the required movement).
For more information, see Work with IMUs.