IR Emitters and Detectors. Which is which?

MikeK

I've got IR emitter/detector pairs. They both look like 5mm LEDs, except one is in clear plastic and one is in blue plastic. Is there a standard as to which one is the blue one?
Thanks,
Mike

Mikerocontroller

· I have an emitter-detector pair from Radio Shack (pt# 276-142).· The package indicates that the tinted one is the emitter.

Ugha

Most digital cameras and webcams (although some of the better/more expensive ones have filtering) can detect infrared. Try
pointing a webcam at them when they are running.

MikeK

Thanks. I'll give it a try.

Beau Schwabe

MikeK,
·
If you have a bright flashlight (<--White LED)·and a Digital Multi-Meter you can determine which is which by connecting the leads and making a few observations.
·
The Detector will consistently show a voltage decrease when the flashlight shines on it, while the Transmitter will consistently show a voltage increase when the flashlight shines on it.
·


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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

Peter Jakacki

Put your meter onto the diode range and connect it to each device and reverse the leads until you get a reading of around 1V in one direction and open in the other as the IR led exhibits a forward voltage drop or around 1V at very low currents.

Then you can double check the sensor as Beau pointed out, perhaps even using the IR led as the light source.

*Peter*

MikeK

The blue components are emitters. I believe I got them at RS at one point. I used a variety of the suggestions to determine that and confirm.
Thanks again.
Mike