Sensing wavelengths of light

I have recently started a new project, but I have gotten stuck.

I'm trying to measure the wavelengths (nm) of an LED going trough a transparent object.
I can't seem to find the right sensor. Needs to go from 300nm to 700nm.

If you know of one or if you know of another way to do please let me know. That would be great :slight_smile: :slight_smile:

1 Like

Most LEDs only put out one or just a few discrete wavelengths. What kind of LED is this? For most, you would just automatically know that it is the wavelength of the LED or one of the wavelengths that LED produces. If you're talking about an RGB LED then the different colors don't correspond to different wavelengths of light, they correspond to different mixes of three discrete wavelengths. It's your eye that is making different colors out of that.

So the question is, do you really want to measure wavelength or color?

You might consider the Sparkfun spectral sensor breakout.

The AS7262 spectrometer detects wavelengths in the visible range at 450, 500, 550, 570, 600 and 650nm of light each with 40nm of full-width half-max detection. For sample illumination over the full wavelength range, you would need a good white light source, not an LED source, for the measurements.

Delta_G:
Most LEDs only put out one or just a few discrete wavelengths. What kind of LED is this? For most, you would just automatically know that it is the wavelength of the LED or one of the wavelengths that LED produces. If you're talking about an RGB LED then the different colors don't correspond to different wavelengths of light, they correspond to different mixes of three discrete wavelengths. It's your eye that is making different colors out of that.

So the question is, do you really want to measure wavelength or color?

Yes I need to measure wavelength like UV light after the light goes through colour filters and different liquids

You didn't answer my question. What kind of LED? What wavelengths of light is it producing?

Are you expecting that the color filters are going to change the wavelength?

JakeDavies4378:
Yes I need to measure wavelength like UV light after the light goes through colour filters and different liquids

So you need an optical spectrum analyser, aka spectrophotometer for visible + near UV? That's a serious
piece of kit, not a single sensor, as far as I know.

However if very cause resolution is OK, the AS7262 seems like the way to go.

Yes I need to measure wavelength like UV light after the light goes through colour filters and different liquids

The wavelength of light is set by the light source, not by the sample.

Can you explain more clearly what you are trying to do?

The OP means spectrum, not wavelength, I think, and is assuming white light (not aware
of how most white LEDs are appalingly poor white light sources!)

MarkT:
The OP means spectrum, not wavelength, I think, and is assuming white light (not aware
of how most white LEDs are appalingly poor white light sources!)

Quite right. I think there are incandescent lamps made just for such applications. The glass of the lamp will filter out some wave lengths.

Paul