hughes@ux.acs.umn.edu (Steve Hughes) (11/21/90)
I'm writing a stack that presents digitized photographs of kids displaying various facial emotions (a "facial affect task") to be run as part of a research study with various brain-injured and normal children here at the U of Minnesota. The task requires that two pictures be presented in sequence, .5 seconds display time for each, with .5 seconds between the two pictures. THEN there is a period of 2.5 seconds wherein the experimenter is supposed to strike a key in response to the kid saying "same" or "different" (emotions being displayed). There is a total of 30 pairs of stimuli, with 2.5 seconds between each pair. This is not a difficult thing to do, thanks to HyperCard 2.0's picture command! I'm flashing these pictures on a IIci, with an 8-24 video card (in 256 grey scale mode) and Apples 13" color monitor. We load the stimuli pairs with picture "affect1",file,plain,false picture "affect2",file,plain,false and then set visible of window "affect1" to true wait for 30 ticks set visible of window "affect1" to false wait for 30 ticks set visible of window "affect2" to true wait for 30 ticks set visible of window "affect2" to false to present them. This is pretty elementary stuff, and we get some flicker, but it seems to be acceptable to those in charge (though if anyone can show me a better way, a flicker-free way, I'd be interested in knowing it--note that these are 256 level gray-scale pict files). The problem is in reading the keyboard for a function key strike during my 2.5 second interval between stimulus pairs. I'd like to test for a functionkey (F1 and F2) and record the keystroke while waiting my 2.5 seconds, yet I can't seem to get the functionkey function to function the way I want it to. I'd like to do something like: put the ticks + 2.5 * 60 into endtick --2.5 seconds * 60 ticks/sec repeat until the ticks >= endtick if functionkey then <do something to get and record which key was pressed> end if end repeat But this doesn't do it for me. Any advice? Is there an XCMD that works with HyperCard 2.0 that will help me with this? Thanks for any help! Reply here or email me if appropriate. -Steve Hughes hughes@ux.acs.umn.edu Steve Hughes Psychology Department Elliott Hall University of Minnesota Mpls MN 55455