Cp Spectro Print

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In partial Fulfillment to the requirements of Chem 127:

BarBa |biadomang | Cua | DELA cruz | de chavez|dulos

Manatad | monroy | Narciso | nepomuceno | Pilar| Tan

Submitted to:Dr. Voltaire organo

The Cellphone Spectrometer:

What It Is, How It’s Made & How It Works



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Spectrometry:More than the purview of expert engineers

“In order to get across the idea, 'I can do it, and Ican see it, and I can understand it,' they've go tobuild the instrument themselves.”

- Alexander Scheeline, 2009

Light

Source

Sample

Holder

Diffraction

Grating

Detector



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Meet Alexander Scheeline.

He wanted to seestudents using their

cellphones in class. Not for texting or surfing the

Web, but as ananalytical chemistry

instrument .

Truly, all you need are afew basic, inexpensive

components and acellphone to build a

spectrometer .



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The cellphone is the photodetector thateverybody has.

If you can get the picture from the

cellphone into thecomputer , it's only

software that keeps you from building a

cheapspectrophotometer.

And so, Scheeline wrote the

software.



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The Cellphone Photodetector:Converting light into numbers

1. Light reaches thecamera’s detector

surface. 2. Regions in thedetector are sensitiveto color.

(Red, Green, Blue)

3. More light, moreelectrons, more charge.

4. Analog-to-DigitalConverter: Generates anumber proportional to

amount of charge.

The resulting number corresponds toa bitmap (BMP) file.

This is too large, so a compressedversion, JPEG, is usually used.

The software that Scheeline wroteanalyzes JPEG files, and it’s availableonline…

… so yes, we did it.



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The Cellphone Spectrometer: A construct out of household materials

All you actually need is a shoebox, an old disc youdon’t use anymore, some pipes, a camera-equipped

cellphone… and of course, knowledge ins ectrometr .


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The Cellphone Spectrometer:1. You need a sample first!

Anything colored can be your sample.Our group chose to analyze a yellow-orange colored

drink, melon juice.


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The Cellphone Spectrometer:2. Lights off, please.

Turning off the light is imperative!It will minimize the amount of stray

light .



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The Cellphone Spectrometer:3. The sample’s position matters.

The sample is now ready for analysis!



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The Cellphone Spectrometer:4. Don’t forget to take a blank!



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The Cellphone Spectrometer:5. Take a shot now.



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The Cellphone Spectrometer:5. Here’s the interface of Scheeline’s software.



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The Cellphone Spectrometer:6. Load reference, load sample.

Sample Referenc

eUpload the pictures into the program.

Load the picture of your reference reading by going to'file > load reference (right) > (your directory

pathway)', then do the same to your sample spectrum'



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The Cellphone Spectrometer:7. There’s a red end; there’s a blue end.

Once the spectra areuploaded, simply click on one

side of the sample spectrum on your screen.

A box will appear, asking you

to specify if it is the red orblue end of the spectrum.

Choose the correct answerand repeat the procedure

at the other end of yoursample.

There should now be a greenline connecting the red andblue ends of your spectrum.

Run through the sameprocedure with your

reference spectrum.



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The Cellphone Spectrometer:8. The sample and its absorbance

Spend a bit of time exploring the 'Plot trace selection'portion.

‘ ’ ‘



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The Cellphone Spectrometer:9. The sample and its transmittance


‘ ’ ‘



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The Cellphone Spectrometer:10. The sample and its intensity


‘ ’ ‘



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Yes, you can make your own cellphonespectrometer, too!

Just visit the site below for more details!

http://www.asdlib.org/onlineArticles/elabware/Scheeline _Kelly_Spectrophotometer/index.html

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Cp Spectro Print