audience participation controls

[Dave Halliday]

>>......a performance/musician has asked
>     <<snip>

>>I think somebody once said torches on LDRs.....I don't think the

>>ambient light interference would allow this, but perhaps laser pointers,

>>though this is getting too expensive (not everything you throw into an

>>audience comes back). Ultrasonics?


>     How about having lightsensors onstage with a sort of cap to shield 
>     them from the normal stagelightning allowing only light from the 
>     audience entering these lightsensors?


>     Put spotlights on the stage pointing  at the audience and give them 
>     (the audience) mirrors by which they can reflect the light back onto 
>     the lightsensors. 

>     If someone in the audience decided to keep whtever you handover to 
>     them then this setup will not cost much either.


Excellent Idea!!!  You could make this immune to stage lighting
interference by using modulated light.  This would allow a very
large collection area.  Since the light going out would be pulsed
at so many Hz ( say a couple hundred but make it a non-multiple of
60Hz or 50Hz ), you could only accept signal from your collector
which had the same modulation.  "Normal" stage lighting ( mostly DC
with some power line ripple ) would be ignored.


You could use a low powered laser or strobe light flashing so fast as to
appear almost continuous.  Your collector could be an array of Fresnel 
lenses - these can be purchased at some eyeglass stores for flat
magnefying screens for people trying to read.


Off the shelf and fairly cheap...  Good combo...



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