v. ON topic: Infrared control and such

[Paul Perry]

At 11:36 AM 20/04/00 EDT, CCartCat wrote:
>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. 
>There are (roughly speaking) infrared equivalents of LED/LDR's at work here, 
>yes?
........no. There is a photodiode or phototransistor doing the pickup.
They can have a response time in the Megahertz range, as opposed to 5KHz.

>Is there a fair amount of natural ambient infrared in our environment as 
>there is visible light? .......shit yes. More, usually. 
>
>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?......yes, it's modulated & coded
>
>Wireless headphones for quiet TV viewing use infrared also, right?  But I 
>would imagine it would be analog .....no, it's a modulated carrier

> (Does infra. reflect?)....you can do anything with it you can do with visible
light
>
 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. ......the radiation from a domestic 'hot' object is mostly
below the range of
ordinary photoelectronic gear

paul perry melbourne australia