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Hobby Spectrometer ?!?!

Hobby Spectrometer ?!?!

RE: Hobby Spectrometer ?!?!

Nice. I noticed this detail.

"...$249, and it includes two years of free apps."

So after two years, then they want additional app fee per year?

Probably a minor detail. But who knows?

RE: Hobby Spectrometer ?!?!

(OP)
I'm guessing the software would be like Solidworks or any other, subscription or update fees annually. They didn't say much about its ability with metals, though, or its accuracy. Might have to try one out when they become available.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: Hobby Spectrometer ?!?!

Rubbish. You aren't going to tell much about the make-up of anything but pure substances by just looking at its UV/vis/IR reflectance spectrum. Metals? Forget it- this isn't an x-ray fluorescence device.

RE: Hobby Spectrometer ?!?!

"...this isn't an x-ray fluorescence device."

Well lets hope not since it appears to be small enough to carry around in your pants pocket winky smile

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

RE: Hobby Spectrometer ?!?!

(OP)
"You aren't going to tell much about the make-up of anything but pure substances by just looking at its UV/vis/IR reflectance spectrum."

Hmmm, but isn't the public being told this is how we know what stars and planets are made from?

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: Hobby Spectrometer ?!?!

Hmm, I must not have posted a reply like I thought. Hyperspectral processing routinely separates 3 or more substances. There are tons of literature on "end-member" determination. Mineral, vegetation, and improvised explosive device (IED) detection/mapping depends on being able to detect one substance's spectrum buried amongst a bunch of other spectra.

TTFN
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RE: Hobby Spectrometer ?!?!

Picking out EMISSION spectral lines through the vacuum of space is easy enough- but merely knowing for instance that something contains carbon, oxygen and hydrogen here on earth really doesn't tell you much! Even knowing the ratios of the elements (which you cannot get from an absorption spectrum!) tells you nothing. Yes you can get lots of useful composition information from a mixture via a FTIR scan for instance, but reflectance spectroscopy is a different matter entirely. Picking out a substance from a mixture as complex as FOOD without doing any chemical separations first or diluting so you can do transmittance rather than reflectance is a totally different matter!

RE: Hobby Spectrometer ?!?!

(OP)
Correct me if I'm wrong, but refractometers are more specific to fluid concentration levels, not so much with solids.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: Hobby Spectrometer ?!?!

The typical refractometer could be used to determine the index of glasses, but the typical application shown in the cited product assumes that you are tweaking a process with known constituents with know correlation between index of refraction and material composition. Given a material with unknown composition, a refractometer wouldn't be able to tell you much.

TTFN
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RE: Hobby Spectrometer ?!?!

Brings to mind this Far Side comic:

http://www.sir-ray.com/Microscope%20History.htm

That's about how much a near infrared reflectance spectrum will accurately tell you about a multicomponent mixture, even with Fourier analysis. Pure substances? Sure, it can pick out some easy ones by looking for telltale peaks for certain functional groups, but it will also be very easily fooled. Very useful analytical tool in concert with others, but nothing like what these guys are pitching- they're talking about it like it's going to be the equivalent of a Star Trek tricorder...The claims made in the article provided in the link are, in my opinion, very exaggerated to say the least. Not wasting my time to see what is claimed in the Kickstarter campaign that apparently raised $2 million for this idea.

RE: Hobby Spectrometer ?!?!

Again, emission spectra and absorption spectra are totally different beasts. If your cellphone is going to pull a vacuum and then vapourize the item it is analyzing using a plasma arc, perhaps now we're talking! But holding a brick up to the light doesn't tell you much.

RE: Hobby Spectrometer ?!?!

Below are some representative reflectance spectra. While some materials are not particularly distinguishable in the visible band, they do have spectra in other bands, such as LWIR or SWIR.

TTFN
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Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers


Of course I can. I can do anything. I can do absolutely anything. I'm an expert!
There is a homework forum hosted by engineering.com: http://www.engineering.com/AskForum/aff/32.aspx

RE: Hobby Spectrometer ?!?!

If your argument is that you could make a reflectance spectrophotometer which was able to identify a few pure substances, absolutely I'd agree. You'd do even better with transmission so you can get the dilution correct. You might even be able to detect some of those substances in some mixtures. But most everyday mixtures have reflectance spectra that look like those camo paint and red brick spectra, all the way from the far IR to the vacuum UV. A few hills here and there- maybe the odd notch.

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