Using the DataLogger

The DataLogger is a versatile tool designed to facilitate the logging of experimental data in Vizard VR experiments. It can capture a variety of data points, including gaze position, head position, custom events, and more. This document outlines how to expand its functionality as needed. See also ExampleScripts- Data_Logger_Adding_Data.py or Data_Logger_Adding_Data_360.py

Adding Custom Data Points

To add custom data points to the logger:

• First adjust the settings to allow custom data tracking by adding these lines before importing sightlab:

import settings

def update_settings(setting_name, value):

    setattr(settings, setting_name, value)

update_settings('CUSTOM_TRACKING_DATA', True)

from utils_sightlab import sightlab

• Define the additional data points as column headers in the additional_columns parameter when initializing DataLogger.

• Create a function that will retrieve the values for these data points. This function should return a list of values in the same order as the headers specified in additional_columns.

And here's an example for multiple objects: #While true is so that it runs every trial, but can also use range of number of trials. 

global logger

while True:

def get_additional_data():

rHandPos = sightlab.rightHand.getPosition()

rHandPos = [round(x, 3) for x in rHandPos]

headOri = sightlab.objects[2].getEuler()

headOri = [round(x, 3) for x in headOri]

return rHandPos + headOri #note you may need to put brackets around data

yield viztask.waitKeyDown(' ')

logger = sightlab.DataLogger(sightlab.participant, sightlab.trialNumber + 1, sightlab.use_vive_pro,  

additional_columns=['Rhand X', 'Rhand Y', 'Rhand Z', 'HeadYaw','HeadPitch', 'HeadRoll']+['FLAG'], start_time=viz.tick())

viz.sendEvent(TRIAL_START_EVENT)

logger.start_logging(additional_data_func=get_additional_data)

Starting and Stopping the Logger

To start logging data:

logger.start_logging(additional_data_func=get_additional_data)

To stop logging data, usually at the end of a trial or when pausing the experiment:

logger.stop_logging()

Changing Directory where Data is Saved

• directory: The relative path to the directory where the data files will be saved.

• Example: (note that  the ".." may be necessary if your folder is one up from the utils folder

logger = sightlab.DataLogger(sightlab.participant, sightlab.trialNumber + 1, sightlab.use_vive_pro, additional_columns=['Condition'], directory= '../DataFiles/',start_time=viz.tick())

Note: if you change the directory, you will then have to redirect the SessionReplay script to find the csv file for the heatmap: 

data_dir = 'pathToYourDataDirectory'

Logging Flags or Events

To log specific events or flags during the experiment, such as a button press or a significant event:

def set_flag(flag_text):

 logger.set_flag(flag_text)

You can call this set_flag function at any point in your experiment to log the occurrence of an event.

Starting and Stopping Logging

Here's an example where a True/ False Boolean can toggle whether a trial logs or does not log data. This can be used alongside a STIM file to set blocks of practice trials, or certain trials where data is not collected

For multi -user see Data_Logger_Adding_Data_Server in the ExampleScripts folder

Adding to Existing Tracking Data.txt File

Adding to the existing tracking data file is not the recommended workflow (recommended to use the custom data_logger) as it involves modifying the sightlab module and is a bit more advanced. See this page on how that is done.