Unknown IR LED - how can I find the wavelength?

[etmabreu]

The title almost says it all.

I have an IR LED in a remote control circuit and I may need to add an extra LED.
The existing LED has no special mark, is a simple 5mm clear LED.
How do I find the correct wavelength so I can buy similar LEDs?

 

[mikerf]

LEDs are not pure like lasers are, your IR LED will be producing a relatively broad range of wavelengths.. and your receiver will be looking for a relatively broad range too.

whatever you try, your chances of success are high.

 

[biff44]

true that. But if you really need to know, borrow an optical spectrum analyzer from a pal

 

[mikerf]

Or get your mits on a webcam without an IR filter (remove it if it has one).. use a CD as a grating, and you have a VERY crude spectrometer.

take a look at this:

https://www.cs.cmu.edu/~zhuxj/astro/html/spectrometer.html

 

[biff44]

Or get your mits on a webcam without an IR filter (remove it if it has one).. use a CD as a grating, and you have a VERY crude spectrometer.

take a look at this:

h**p://www.cs.cmu.edu/~zhuxj/astro/html/spectrometer.html

that is pretty impressive!

 

[FvM]

IR LEDs are either 850 or 950 nm. Industry standard remote control receivers are optimized for 950 nm IR LEDs, you can use them without further checking the presently used LED, I think. Other important parameters are maximum current (usually about 100 mA continuous) and half angle of the radiated beam.