Saccade information missing from hdf5 file (Tobii eye tracker + PsychoPy)

Hi all,

I am currently designing an eye-tracking experiment using PsychoPy and a Tobii eye tracker. When I test out the compatibility of the two, I generate an hdf5 file that has various header titles such as ‘experiment_id’, ‘time’, ‘left_gaze_x’, ‘left_gaze_y’ etc. The majority of the data that I am getting is useful, however, I seem to not be recording velocity or acceleration data. There are columns dedicated to recording this data, such as ‘left_velocity_x’ and ‘left_velocity_y’, but while the data for the x and y gaze co-ordinates are being recorded, the values in the velocity columns is solidly 0.0 for every row.

Has anyone else encountered this issue, and if so, is there a way that I might be able to fix it?

Thanks in advance!