# inexpensive spectrometers - useful?



## N8N (Jul 3, 2013)

I wasn't sure where to put this, so if this needs to be moved I understand...

anyway, another thread got me thinking about this. If I, as a consumer, wanted to measure the wavelength of a single color LED, are any of those inexpensive handheld spectrometers (I assume that they're basically a diffraction grating and a scale) accurate enough to tell me any meaningful? If so, are there any specific recommendations?

Basically what I would like to see is if some red LEDs are really the wavelength that the vendor claims they are. No reason to doubt, but I'm just curious how best to double-check myself.


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## SemiMan (Jul 3, 2013)

N8N said:


> I wasn't sure where to put this, so if this needs to be moved I understand...
> 
> anyway, another thread got me thinking about this. If I, as a consumer, wanted to measure the wavelength of a single color LED, are any of those inexpensive handheld spectrometers (I assume that they're basically a diffraction grating and a scale) accurate enough to tell me any meaningful? If so, are there any specific recommendations?
> 
> Basically what I would like to see is if some red LEDs are really the wavelength that the vendor claims they are. No reason to doubt, but I'm just curious how best to double-check myself.



If you calibrate the diffraction grating with LEDs with known wavelength peaks then there is no reason why you cannot estimate what your wavelengths are to at least some degree of accuracy. If I remember correctly, Lumileds superflux LEDS used to be binned by wavelength, so if your order included that information, you could get amber, orange and red in fairly accurate wavelengths and use that to create a measurement baseline. OSRAM and Lumileds also have 660nm.

It would be dirt cheap to try.

A real spectrophotometer is going to costs approximately $1000 for the cheapest models.


Semiman


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## Anders Hoveland (Jul 5, 2013)

http://www.youtube.com/watch?v=IA5BTD-aelo
http://www.wired.co.uk/news/archive/2010-10/11/camera-phone-spectrometer 

If you have the money, you can buy a "relatively" inexpensive used spectrometer on ebay:
http://www.ebay.com/itm/Compact-Fib...ultDomain_0&hash=item336d192278#ht_866wt_1185


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## krazy (Oct 27, 2013)

IIRC, spectrometers can be used to detect CO2 presence. Otherwise, you need an expensive digital meter. So there's that...


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## degarb (Feb 16, 2014)

Anders Hoveland said:


> http://www.youtube.com/watch?v=IA5BTD-aelo
> http://www.wired.co.uk/news/archive/2010-10/11/camera-phone-spectrometer
> 
> If you have the money, you can buy a "relatively" inexpensive used spectrometer on ebay:
> http://www.ebay.com/itm/Compact-Fib...ultDomain_0&hash=item336d192278#ht_866wt_1185




Interesting links. Yeah, I think toys like this have a price point around $40.

I was wondering if a simple prism could be used to split up the light, and lux meter to graph the relative lux of each six outgoing lights. If this could tell us anything useful when comparing different lights and the ratios. 

http://www.selah.k12.wa.us/soar/sciproj2001/CassiT.html Hmm. Science fair is coming up for the parents to do the kids work. Wonder what other projects could be tested.


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