1
\$\begingroup\$

w I have a dust sensor that emits LED light, scatters the light of the material and records the light intensity via a photodiode. I know the LED will emit light in the infrared range. I want to know the (approximate) wavelength since the infrared range is quite large.

Is there any way I can find the wavelength of my IRED LED (page 2) based on the spec sheet, particularly pages 4 and 5.

Infrared LED Sp.sheet

\$\endgroup\$
1

2 Answers 2

0
\$\begingroup\$

The answer is: We don't and can't know.

It simply doesn't say what the wavelength is, which means that there is not guarantee from the manufacture that the wavelength is anything specific. It might be one wavelength on one unit, and a completely different wavelength on a different unit. If you are building a product, and the wavelength is important to you, then you must choose a different sensor that calls out the wavelength in the datasheet.

You can't even buy and test 100 units, measure their wavelength, and then expect the 101st unit to have the same wavelength-- since Sharp is allowed, according to their datasheet, to substitute a different IR LED in that assembly with another IR LED that has a very different wavelength.

\$\endgroup\$
0
\$\begingroup\$

Nope. It doesn't say but IR LEDs are usually 970 nm. Not always, but often. Why do you care anyways?

\$\endgroup\$
2
  • \$\begingroup\$ Im using it for optical measurements \$\endgroup\$
    – l3win
    Commented May 16, 2013 at 21:48
  • \$\begingroup\$ How can I easily measure the wavelength of the IRED LED in the box? Is there a "wavelength probe" or something I can use? \$\endgroup\$
    – l3win
    Commented Jul 1, 2013 at 23:27

Not the answer you're looking for? Browse other questions tagged or ask your own question.