OT? Infrared control and such

[CCartCat at aol.com]

Hi--

Been thinking about infrared transmission/reception in remote controls for 
VCR's etc. and wondering how that technology relates to LED/LDRs, the whole 
homebrew vactrol thread.  Neither being an engineer/tech nor someone with 
extended sub-spectrum vision, I'm generally in the dark on this.

There are (roughly speaking) infrared equivalents of LED/LDR's at work here, 
yes?

Is there a fair amount of natural ambient infrared in our environment as 
there is visible light?  

I gather from using a remote in proximity to an electric guitar and picking 
up the electronic noise that the remote is sending pulses to the VCR via 
infrared flashes.  While this is probably the logical format of commands 
received by the VCR, is this also to cut through any ambient infrared in the 
room?

Wireless headphones for quiet TV viewing use infrared also, right?  But I 
would imagine it would be analog and thus subject to, I dunno, a hot turkey 
sandwich swamping out the signal.

Getting closer to home, that is, topic, the D-Beam controller uses infrared, 
correct?  Any idea how?  (Does infra. reflect?)

Generally, I'm trying to get an idea of how these other infrared devices work 
so I'd have some informed idea how one would use infrared (much) more simply 
in an analog/CV, homebrew vactrol, flashing goofytech theatre of light sort 
of way.  It'd be nice to know, for instance, about the nature of 
infrared--like whether it's a good idea to put a infrared LDR near something 
hot unless you want a high infrared offset that any other source would have 
to spike above.  

Thus, all these questions . . . <g>

Thank you for your time,
Kevin Seward