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Need Infrared LED expert Opinion...

Hello.. I would like to build an infrared repeater device for my home theatre setup. My big screen TV has an output on the back for the use of adding additional, hardwired, IR led emmitter cables (Although I plan on building an interface so that many IR emitters could be attached and not 'tax' that TV's ability to drive the LEDS). These individual cables would be routed to the various components and attached directly near the IR receiver window. My question, is their enough IR energy from a generic RED led to activate the IR receiver(s) since the proximity of the led emitter is so close? If so, would I need to drive the red leds with an abundance of current?

Your help is appreciated.

Jim

Reply to
Jim Flanagan
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I read in sci.electronics.design that Jim Flanagan wrote (in ) about 'Need Infrared LED expert Opinion...', on Mon, 3 Jan

2005:

You can easily get proper IR LEDs. Do you need to use red ones for some secondary reason?

--
Regards, John Woodgate, OOO - Own Opinions Only. 
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Reply to
John Woodgate

Yes.. I surely realize that. I should have mentioned that I have a 'bushel' of regular red leds and simply didn't want to wait for delivery of the IR versions.

Jim

Reply to
Jim Flanagan

There will be sod all IR energy from a red LED so the question should probably be how good (or bad) are the IR filters on the receivers.

Check out a datasheet for a BPW34F which is a cheap photodiode with built in IR filter. It shows zero % response below 760nm. The 'coldest' red LEDs are about 700nm. I haven't seen a spectrum for such a LED but I guess between the LED and the filter you will be about 10,000:1 down on an IR LED.

If you have a 'cold' red LED and poke it right next to the receiver there is some chance it will work.

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