strange idea....now even strangerer

[Carlos Vila Deutschbein]

On Wed, 22 Dec 1999, Bob Gonsalves wrote:

> >This reminds me of another topic. Are there some easy things one can do with
> >TV-sets or something, to help my friends psychedelic band (i am the
> >preliminary mixer) get a show? They've got an oil-filter, but they could
> >really use some more stuff. Is their an easy way to generate video-signals
> >to? (I haven't studied my course on media's yet...)
> 
> 
> Large magnets usually do interesting things to (junk) television sets...


This is a nice experiment you can do with a TV set and a Video camera: I
read it in a book about Chaos Theory and it deals with positive and
negative feedback:
NB: Please forgive my dodgy English
Put the camera in front of the TV-set facing each other at a distance of
about 3 meters. Connect the cameras output to the Video In of the TV Set.
Now you should see in the TV-set: a screen in a screen in a screen...
The funny bit comes now: Adjust the cameras zoom (or distance to the
screen) so that it just the same size as the screen (Unity Gain Loop)
Now turn down the brightness and contrast of the tvset so that the
feedback system only reacts to a very bright "impulse" for example a match
in front of the cameras objective. Light the match and quickly put it away
from the camera. 

Ideally You should see the bright light 
in the TV-set feedbacking.Ideally it should not change size or position.
The even funnier bit comes now: rotate the camera slightly (in the axis
formed by the camera and the TV-set) A bright point should now rotate
around the screen buiding up chaotic patterns never repeating. By slightly
moving the zoom you can force positive or negative feedback. 
It works best in dark environments and with the camera and TV set fixed on
a stand. 
Someday I will try it  :)


==============================================================       
    Carlos Vila Deutschbein
    e-mail: si04697 at salleURL.edu
    www: http://www.salleURL.edu/%7esi04697
    Barcelona -- Spain
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