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03 Sep 17:29 255,163 views | Last edited by tonyc 3 months ago | shortlink

Oil testing kit: Making measurements

by ernestootero about 2 hours ago | 0 | 8 views | 1

Back to work. Yesterday recorded most of the spectra. It was necessary to add two layers of the c...

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Oil sample concentration session at Barnraising

by warren 4 days ago | 2 | 68 views | 1

We're having a great discussion on how to concentrate oil samples collected from sheens and other...

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An "open open hardware" development cycle

by warren 9 days ago | 2 | 125 views | 2

Greetings! Starting today, we're adopting a more open, but also more integrated development proce...

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Slit holder for Desktop Spectrometer

by warren 12 days ago | 1 | 171 views | 1

What I want to do Drawing on input from @stoft (here) and @ygstcu, and ideas @mathew's posted in...

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Separating Oil from Water by Freezing the Water

by Matej 12 days ago | 6 | 210 views | 3

What I want to do I attempted to extract various types of oils previously mixed with (tap) water...

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Oil testing kit Beta programme - Scanning the unknown & the not so well known…

by Cindy_ExCites 16 days ago | 4 | 287 views | 2

Oil testing kit Beta programme - Scanning the unknown & the not so well known… Date: 5/Nov/2...

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Oil Testing with the Green Team

by stevie 16 days ago | 0 | 135 views | 2

I have been working to refine the workshop that will support the new Public Lab Oil Testing Kit. ...

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Oil Testing Kit -- Assembly & Calibration!

by _mahsa_ 17 days ago | 3 | 286 views | 3

Hi, I'm Mahsa a member of the Oil Testing Kit beta program and below you'll find my experience as...

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More research on "spectrometer" »

Title Last edited Edits Pageviews Likes
Refinery Watching 10 days ago by warren 18 8,001 3
Oil Testing Kit Beta 13 days ago by stevie 54 3,156 0
Desktop Spectrometry Kit 3.0 22 days ago by tonyc 44 16,317 4
Oil Testing Kit about 1 month ago by stevie 123 17,766 5
Smartphone spectrometer about 1 month ago by tonyc 27 34,174 3
Spectrometer construction 3 months ago by wwd2010 8 22,949 2
Oil Testing Kit Construction 4 months ago by warren 9 1,948 0
Desktop Spectrometry Kit 5 months ago by warren 46 47,391 9
Desktop Spectrometer 3.0 parts list 5 months ago by warren 3 7,381 2
Ottawa 8 months ago by warren 2 3,576 2
Spectrometry Sampling 9 months ago by OpenSourceScience 22 11,214 1
Foldable Mini-Spectrometer 10 months ago by warren 19 82,854 7
Pesticide Detection Methods Development about 1 year ago by silverhammer 27 9,345 6
The Homebrew Sensing Project about 1 year ago by Becki 5 5,337 0
Oil Testing Kit Literature about 1 year ago by mathew 5 3,139 1
Spectrometer History over 1 year ago by mathew 4 6,462 0
Oil Testing Kit Illustrations over 1 year ago by warren 3 2,997 0
spectrometer-media over 1 year ago by warren 2 4,228 0
How to make a homemade spectrophotometer over 1 year ago by Haripriya 3 9,240 3
Spectrometer Curriculum almost 2 years ago by bicwood 25 9,808 3
How Kickstarter backers will use the spectrometer about 2 years ago by Becki 4 8,540 0
Countertop Spectrometer about 2 years ago by warren 7 4,616 0
Spectrometry Meetups over 2 years ago by liz 3 2,764 1
Suggested Spectrometer Readings over 2 years ago by PeterDavidowicz 10 4,364 0
Spectral Challenge ideas over 2 years ago by philippg 18 4,679 3
Spectrometry health applications over 2 years ago by warren 10 4,303 1
DIYBIO Ideas and Applications over 2 years ago by briandegger 3 3,319 2
Spectral Challenge Teams over 2 years ago by warren 1 2,603 0
Spectral Challenge over 2 years ago by warren 30 6,843 1
Spectrometry FAQ almost 3 years ago by warren 1 2,802 0

Desktop Spectrometry Kit v3

The standard -- plugs into your laptop

Build one Buy one

Smartphone Spectrometer

Rigid plastic version which attaches to your smartphone

Build one

Foldable Mini-Spectrometer

Cheap, easy, starter version for smartphones and webcams

Build one Buy one

Public Lab's Do-It-Yourself spectrometers are designed to help everyday people detect pollutants where they live.

Our community has been working since the 2010 Deepwater Horizon oil spill to develop a cheap, open source, Do-It-Yourself spectrometer which we hope to use to identify oil pollution in soil and water, as well as a range of other possible contaminants.

What's spectrometry?

Colored light is often a blend of different colors. A spectrometer is a device which splits those colors apart, like a prism, and measures the strength of each color. A typical output of a spectrometer looks like this spectrum of the daytime sky, with the actual light spectrum at the top and the graph of wavelength (horizontal axis) and intensity (vertical axis) below:


Types of spectrometry

There are different ways to use spectrometers, and the key difference is how you illuminate your sample.


This project focuses on fluorescence spectrometry in order to identify oil pollution samples, which is where a high-energy light like an ultraviolet laser is used to excite a sample so that it fluoresces, or glows.

See the lead image of this page for a diagram of a fluorescence spectrometer setup. Since different oils fluoresce in different colors, this technique can be used to match an unknown sample with a reference sample to identify it.

Read more on the Oil Testing Kit page »



Emission spectroscopy is the kind often done in the classroom, where burning a material emits a colored flame. A spectrum of this colored flame can be used to match a material, but it can be unsafe to burn unknown samples, so we have primarily begun to use this technique to attempt to monitor distant flares, for example at gas refineries in Louisiana, to try to detect heavy metals.

[image of refinery watching]


Absorption spectroscopy -- shining a full-spectrum light like a halogen or incandescent (not a fluorescent or laser) through a sample to see what colors are absorbed -- is a bit more difficult in the visible light range, as most of the "fingerprint" features of spectra are too long or too short wavelengths for our webcam-based devices. However, a considerable amount of work has been done on absorption spectrometry of:

Make a spectrometer

The links at the top of the page offer step-by-step instructions on making your own spectrometer. Our main design, the Desktop Spectrometer, features:

  • around 400-900 nanometer range, maybe wider (what you can see with the naked eye, plus some infrared)
  • 1-5 nm spectral resolution
  • 20-30 samples per second
  • ~ $15 in materials
  • < 1 hour construction time
  • web-based, open-source software


Once you've built a spectrometer, there are many ways to improve it -- by using a narrower slit, darkening the interior, using a better camera, and more. For upgrading the USB webcam-based Desktop Spectrometry Kit, see the Upgrades section of its documentation.



Along with the physical devices, the Public Lab community has also developed Spectral Workbench, an website to capture data with your spectrometer, analyze and compare spectra, share them in an open database, and comment and collaborate with others.

The software includes:

  • direct connection to your USB-based or smartphone-based device
  • calibration, comparison, and matching tools
  • XML, JSON, and CSV data download
  • a JavaScript API
  • offline mode
  • read more in the documentation


Frequently Asked Questions can be found here »


This document, and this methodology, is still under active development. What you see on this page is only the best attempt so far at collating and presenting the work of Public Lab contributors to date. Some of the challenges that remain include:

Other uses

While many of us have focused on identifying oil pollution with fluorescence spectrometry, there are many other uses for cheap, open source spectrometers, and many other ways to use a spectrometer.


In 2012, Public Lab ran a Kickstarter project to distribute an early version of our DIY spectrometers to over 1600 people. The video is a bit out of date, but is still a compelling way to understand what we're attempting to do:

The Homebrew Sensing Project is made possible in part by the generous support of the John S. and James L. Knight Foundation, Knight News Challenge: Health.


Tags: spectrometer list:plots-spectrometry tabbed:notes tabbed:wikis tool