[PD] Syncing an event with refresh rate in GEM

[chris clepper]

You need to raise the gemwin framerate.  Just create the object like this:
[gemwin 50] and you should see all of the flashes.  Also, setting the gemwin
to the refresh rate of the display might be best.

On 10/11/07, Batuhan Bozkurt <batuhan at batuhanbozkurt.com> wrote:
>
> Hi,
>
> A friend from our schools psychology department wants to use PD and GEM
> for an experiment. Here is his question and attached is the example
> patch. We need you help on this. Thanks.
>
> -------------------------------------
>
> OK, this is the patch that I'm going to use to conduct a research on
> cross-modal interactions in human perception. I'd be happy to fill
> anyone in on the topic because generally human cognition is fun to poke
> around.
>
> So the required stimuli are a "beep" sound (which is a 3.5khz sine with
> 7 ms duration) and a "flash" (which is basically a white circle visible
> only for 20ms).
>
> The problem is, it is very hard for an object to "flash" with this short
> duration. If you look at the patch you'll see that less than 50% of the
> trials do not produce anything.
>
> I have to come up with a workaround to this and I thought maybe if I can
> syncronize the onset of the flash with the refreshing rate, I can at
> least make the disk visible for all of the trials. I can sacrifice the
> precision in terms of duration but that is bound to happen I guess.
>
> I made this patch on windows with my laptop with a poor refreshing rate
> and another laptop with Macosx did not perform any better on the
> task(they are both 60hz screens). But I am guessing that a non-lcd
> monitor may do better? Any comments or suggestions on this?
>
> Relevant information on the stimuli and the procedure can be found in
> this reference article for those of you who are interested "Visual
> illusion induced by sound" by Ladan Shamsa, Yukiyasu Kamitanib, Shinsuke
> Shimojoa.
>
>
>
> #N canvas 78 53 295 395 10;
> #X obj 13 248 gemhead;
> #X msg 101 259 0 0 0;
> #X obj 13 311 disk 3 40;
> #X msg 72 173 255 255 255;
> #X obj 72 147 bng 15 250 50 0 empty empty empty 0 -6 0 8 -262144 -1
> -1;
> #X text 158 232 problem number;
> #X obj 72 200 t b l;
> #X obj 20 30 cnv 15 100 60 empty empty empty 20 12 0 14 -195568 -66577
> 0;
> #N canvas 0 22 454 304 gemwin 0;
> #X obj 132 136 gemwin;
> #X obj 67 89 outlet;
> #X obj 67 10 inlet;
> #X obj 67 41 route create;
> #X msg 67 70 set destroy;
> #X msg 142 68 set create;
> #X msg 198 112 destroy;
> #X msg 132 112 create \, 1;
> #X connect 2 0 3 0;
> #X connect 3 0 4 0;
> #X connect 3 0 7 0;
> #X connect 3 1 5 0;
> #X connect 3 1 6 0;
> #X connect 4 0 1 0;
> #X connect 5 0 1 0;
> #X connect 6 0 0 0;
> #X connect 7 0 0 0;
> #X restore 25 69 pd gemwin;
> #X msg 25 50 create;
> #X text 21 29 Create window:;
> #X obj 101 233 delay 20;
> #X obj 13 284 color 0 0 0;
> #X connect 0 0 12 0;
> #X connect 1 0 12 1;
> #X connect 3 0 6 0;
> #X connect 4 0 3 0;
> #X connect 6 0 11 0;
> #X connect 6 1 12 1;
> #X connect 8 0 9 0;
> #X connect 9 0 8 0;
> #X connect 11 0 1 0;
> #X connect 12 0 2 0;
>
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