Response triggers with accurate timing

[David McFarlane]

Did you see the thread at 
http://groups.google.com/group/e-prime/browse_thread/thread/cfc3d0307d5c7fbd ?

-- David McFarlane, Professional Faultfinder


At 12/13/2010 08:25 AM Monday, you wrote:
>I have been struggling to send triggers to Actiview at the exact time
>a participant makes a response.
>
>I'm running a memory experiment where images are presented in a slide
>object and participants respond by pressing 1,2,3 or 4. I would like
>triggers to be sent a.) at the onset of the slide and b.) at the exact
>point a participant makes a response. I want the slide to run for
>2500ms but responses to be collected for 3700ms in total. (Slide1 is
>followed by a blank screen for 1200ms).
>
>The first issue is fine. I use ...
>
>slide1.onsetsignalenabled = true
>slide1.onsetsignalport = &H378
>slide1.onsetsignaldata = &H05 'send 5 so the value does not clash with
>a possible response.
>sleep (10)
>writeport, &H37, 0
>
>However, I can't get the response trigger to send accurately. I have
>been trying to use slide1.inputmasks.Ispending to collect the
>participant's response and writeport it while the slide is presented.
>Unfortunaltely, this sends the trigger late (looks like it is being
>sent after slide1 has finished running). This remains the case even if
>I set the slide1 duration to 0 . I have also tried setting the slide
>duration in properties to 2500 and using a large prerelease on the
>slide object. This seems to send the response triggers on time
>although I'm only judging this by eye at the moment. However, it
>causes problems with data logging in eprime. I.e Eprime only logs
>about 30% of the responses unless I reduce the prerelease. Also, no
>matter what I try I seem to either get stimulus onset triggers OR
>response triggers but not both. (I am sending 0s after each trigger to
>clear everything but still having problems).
>
>I would appreciate any help with this issue - I have honestly been
>trying for days to sort this by myself. I have found previous
>discussions useful and have looked at some of the sample experiments
>but I still haven't gotten close to solving this problem. I am able to
>achieve most of the subtasks but cannot put them together in a way
>that works.

-- 
You received this message because you are subscribed to the Google Groups "E-Prime" group.
To post to this group, send email to e-prime at googlegroups.com.
To unsubscribe from this group, send email to e-prime+unsubscribe at googlegroups.com.
For more options, visit this group at http://groups.google.com/group/e-prime?hl=en.