Could do with some advice from others who are using stimtracker with Biopac.
We have recently purchased a Stimtracker and I am in the process of testing it out with our Biopac MP35 system with a view to using it to send event markers and by raising and lowering lines to mark onset and end and sending pulses to convey info about different types of stimuli rather than by using the photocell. However, I seem to be getting some small timing errors transmitted to Biopac (between 0.1 and 0.3 secs) when I mark the onset/ offset of the picture stimuli - this seems to be the case whether I use the photocell or the raise/ lower lines event option.
When just sending event markers however they seem to be the right length (with only a timing difference of perhaps 0.01 sec - see attached S/Lab file which shows how I am sending the markers).
Anyone come accross this? Is this likely to taking account of screen drawing time also or am I seeing something else? I have tried 2 different Biopacs and two different PCs (both for sending and recieving) and am still seeing the same anomolies. Any help gratefully recieved! What would be particularly useful would be an example file which someone has used to mark the display of stimuls which has bang on timing in Biopac.
just_stim_events.sl4 (5.72 KB)