Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: Triggering a powerpoint presentation remotely?
References: <[email protected]>
Dale Farmer  writes:

> Hello folks.
>     I'm on a gig where they want me to operate the light board and
> the video projector showing a power point presentation.   And I
> have to flip a cover down over the video projector lens while I'm
> doing lots of cues.  ( Something like 20 cues in 20 seconds
> between the video and light board. )
>     The gotcha is that the video projector is mounted in the middle
> of the audience on a stand, and the light board is at the back of the
> house.
>     I was wondering if anyone knew of a gadget that could be used
> to control the video projector and the PC running power point that
> could be triggered from a DMX cue?   It's too late for this show,
> but that sounds like a nice gadget to know about, or for someone
> clever to invent.

I do not know any clever gadgets for this. 

But I have ideas how this kind of thing could be implemented:

PowerPoint presentation can be moved from the one slide
to another with a click on the mouse button. 
You can make this remotely controllable by modifying a mouse
to have external control. This can be easily done by taking
a suitable relay (for example with 5V or 12V coil). 
Buy a cheap mouse. Open the mouse.
Wire the closing relay output in parallel iwth the mouse button.
Put mouse back together. Plug it to the computer. 
Mouse should work like it worked before.
Now you have a mouse where same function as pressing a 
button can be accomplished using an external signal
(applying power to the relay coil).

Some ideas how to control this relay from DMX light board:
1. Connect a small transformer ("wall wart" giving suitable voltage
   fot the relay coil) to one otherwise free dimmer channel. 
   When power is applied to this channel (using flash button
   or dimmer slider) 

2. Get s amall single channel dimmer/switch box and do what
   is done in option 1.

3. Wire the signal from some DMX-analogue converter box to
   the relay (propable some amplifier in form of transistor
   and external power source is needed). So when slider for
   this channel (or flash button) is activated, the relay
   is activated.

So now you have a DMX-512 controlled PowerPoint show.
This same idea should work with a large number of 
applications  (any device with buttons and which you
can modify to add few wires/relay to it).

If you make black empty slides on power point presentation
you can make the projector not to output anything much
visible (unless the projector has very poor contrast).



-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/