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Basic Electronics » Increase range of an IR LED.

June 03, 2012
by whitehatyoyoer
whitehatyoyoer's Avatar

I recently bought some IR LEDs and photo diodes for a project I'm working on. I'm making a sort of trip beam system. So, I got a small circuit set up to test the LED and diode to learn how use them, it works perfect. But there's only one problem, the range of the LED is only about 5-6 inches, which is way too short for what I need it for. The current and voltage running though the LED is already at it's max, so what could I do to increase it's range?

Thanks,

--Whitehat

June 03, 2012
by missle3944
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Hi whitehatyoyoer,

Solution 1: If you have a garage door look down at the sensor that makes sure nothing is in the way. It is the same concept that you are thinking of. But- if you look close you can see there is a lenses to magnify the IR.

Solution 2: A regular IR tv remote uses IR. But how does it work so far away? It uses a modulated signal. So technically if you modulate the IR LED to 38Khz you should get around the same distance as a tv remote can. I hope this helps!

June 03, 2012
by whitehatyoyoer
whitehatyoyoer's Avatar

Ok, so with the modulation I would use the PWM? I've been trying to find the info I need and the thing that's been popping up is PWM. The way I've come to understand it is you like flicker the LED at a higher amperage that way it goes farther, but since the LED isn't on all the time the higher amperage won't burn out the LED. Do I have that right or am I misunderstanding it.

Thanks alot,

--Whitehat

June 11, 2012
by mongo
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Commercial industrial IRED sensors use lenses to focus the beams into a tighter spot. It doesn't give a laser sharpness but can increase the range considerably. The trade-off is it becomes highly directional and is best suited for fixed beam applications like perimeter alarms, etc.

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