[visionegg] Re: stimulus code outputs

import pygame
pygame.init()
t = pygame.time
a = t.get_ticks()
max = -1
for i in range(1,1000):
   b = t.get_ticks()
   c = b-a
   if c>max:
       max=c
   a = b
   t.delay(10)
   
print max


Can we implement this with numarray, so we can output summary stats,
including: mean, stdev, min, max?


On Thu, 24 Mar 2005 10:23:57 +0100, Christophe Pallier
<pallier@xxxxxxxxxxxxx> wrote:
> Hello Darren,
> 
> Expy is an attempt to re-implement with pygame an old, (venerable ;-),
> DOS experimental stimulator  (EXPE: www.lscp.net/expe) which I wrote 15
> years ago (and is still used nowdays in some labs, for its "perfect"
> timing). Expy is extremely preliminary and we should not have put the
> web page in my opinion, because the program is not really usable.
> Emmanuel Dupoux and I hope to be able to recruit a programmer to pursue
> this project, but we are still looking for funding. Still if you can
> steal any ideas from the project, it would not have been entirely useless.
> 
> I would really like to use python/pygame and maybe VisionEgg to program
> experiments. Actually, a colleague, Mark Welxer, and I, have
> experimented with python a bit and encouraged students to use it: see
> http://cim.risc.cnrs.fr/cours/exphum/projects/projects.shtml),  but I
> need to convinced myself that I can solve some latencies problems (not
> specific to python) for some experiments (I work under Linux; the
> situation may be better with Windows). Just try the following very
> simple minded program to see the latencies you can get:
> 
> import pygame
> a= pygame.time.get_ticks()
> max=-1
> for i in range (1,1000):
>     b = pygame.time.get_ticks()
>     c = b-a
>     if c>max:
>         max=c
>     a = b
>     t.delay(10)
> print max
> 
> (I just got max=140 msec on my system).
> 
> I know VisionEgg offers to swith to 'real-time' mode (SCHED_FIFO in
> Linux), but I have had bad experience in the past with real-time
> processes slowing down other threads (e.g. sound output was choppy). But
> I have not tested VisionEgg enough yet.
> 
> Anyway, maybe a good idea would be to set up some repository of real
> experiments programmed in python, using whatever packages (visionegg,
> pygame or other). This would encourage people to try and test these
> packages.
> 
> Christophe Pallier
> www.pallier.org
> 
> Darren Weber wrote:
> 
> >I notice that pyserial and pyparallel are used by expy - seems there
> >is more than one development effort in python for psychology
> >experiments; I wonder if some sort of integration of efforts might be
> >possible/useful?
> >
> >http://www.ehess.fr/centres/lscp/expy/expy.html
> >
> >
> >On Wed, 23 Mar 2005 09:58:25 -0800, Darren Weber
> ><darrenleeweber@xxxxxxxxx> wrote:
> >
> >
> >>http://pyserial.sourceforge.net/
> >>
> >>
> >>On Wed, 23 Mar 2005 09:47:58 -0800, Darren Weber
> >><darrenleeweber@xxxxxxxxx> wrote:
> >>
> >>
> >>>The visionegg provides display capabilities, but what about output of
> >>>a stimulus code event to an external device.  For example, lets say we
> >>>present an image every 2 sec and there are 5 different categories of
> >>>image.  Each category is given a code, a number between 0-255.  Now,
> >>>we want to send this code to an EEG | MEG | fMRI system that will
> >>>record the timing of this event code during the acquisition of another
> >>>data timeseries.  It is simple enough to save a stimulus/event log to
> >>>a file, but it would be nice to interact with the serial/parallel port
> >>>also.  Is there a command like:
> >>>
> >>>eventCode = 128 # or eventID (maybe event.id)
> >>>event.send.parallelport(eventCode)
> >>>event.send.serialport(eventCode)
> >>>
> >>>I don't have any experience with sending codes to the serial/parallel
> >>>port.  Any tips or reading material would be really useful.
> >>>
> >>>Best, Darren
> >>>
> >>>
> >>>
> >======================================
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> >
> >
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