Missing samples from SMI RED250 Mobile
Did anyone here experience missing samples from the eye recording when using SMI RED250 Mobile eye-tracker?
I recorded pupil size using said eye-tracker (ET) and EEG at the same time. I sent trigger codes via a parallel port to EEG and messages that were in sync with the trigger codes via ethernet to the ET. The ET sampling rate was 250 Hz, but it actually never recorded at 250 Hz. The sampling rate often dropped to 190-220 Hz in a 5-min experiment. In an extreme case, the ET sampled in 18 s instead of every 4 ms.
I wonder if this problem is unique to the PyGaze-OpenSesame combination with SMI or it is the ET that is problematic. As a context, my colleagues who experimented using Presentation did not seem to have this problem.
Any help/idea is appreciated.