light sensor always on during the presentation

Hi, we are using the black lightsensor to detect the onset of the white square with a black background. But today we found that stimtracker sent the onset signal continuously during the presetation of critical stimuli. We have no idea what is wrong. We haven’t changed any settings and it never happened before. Can anybody help?

It seems like you had the right setup. Is the light sensor’s LED on StimTracker’s front panel turning on when you expect it to?

Hi, the light ‘1’ of photocell is on when the white dot appears so is the light of marker on stimtracker.
I think it may have something to do with the threshold of the light sensor. Do you have any recommended threshold?
I just found out that I have failed to post a new thread asking about the threshold…

p.s. our threshold is set at 99. Because we cannot find any stimtracker manual available, we have no idea what this figure means…

The displayed number is just a percentage. It is impossible to recommend a threshold because all monitors are different, and they can be set to different brightness levels.

The documentation is all online, there is no printed manual. You might find the Using StimTracker page helpful. See the main StimTracker support page for a list of all available documents.

Hi, I don’t think the website containing something that I am looking for. If no recommended threshold is possible, how can I know that which threshold is the best for our monitor?

Please see the section Adjusting Thresholds on the Using StimTracker page.