Touch-Screens and RT

[Dr. Dave Hairston]

I don't really know much about tuch screens, but here are my first
thoughts... is the sample/poll rate for measuring the response
location tied to the refresh rate of the screen? If so, it will be
really slow, like 75Hz, leaving you only 15 ms resolution. But i'd
think that would be so aweful that it'd be very jerky, so it probably
isn't and is much higher.

Regarding USB, though, that is correct, there is (potentially) a
timing concern there. The native poll rate (in XP and Vista) of the
USB bus is only about 120 Hz - 8 ms resolution. However - this can be
fixed. I'm sorry I can't recall teh name of teh applet... but if you
Google around, you'll find one (or a few) that allow you to manually
set the rate at which Windows samples the USB bus. I believe the max
is 1200 Hz, which is plenty.
Please note - this affects ALL devices connected via USB, including
your mouse... in fact that's what the sw was originally designed for,
faster mouse movement. If running on a laptop, battery life will
suffer.

-Dave

On Oct 21, 5:18 pm, Marhitomi <m.mikhael... at gmail.com> wrote:
> Some experiments we run use touch-screens. I've been told that there
> is a timing problem - recording reaction times is not very accurate,
> as was determined in 2002 when we first got the screens.
>
> We've had eprime 1 and are upgrading to eprime 2.0. The touch-screens
> we have now are MicroTouch 3M from 2002 and they run on Serial Ports.
>
> Have you had timing problems as well? I need to purchase new machines
> that would not have this problem - any suggestions on models to buy?
>
> I've been told that getting screens with USB connections could affect
> timing? Thoughts?
>
> Thank-you in advance for all your help.
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