Public Lab Wiki documentation

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Absorption and Fluorescence Spectra of Safranin O (aka., Basic Red #2)

by dhaffnersr 4 days ago | 0 | 111 | 0

Origin of the word “science” Latin Scientia- know This is a fundamental tutorial using the Red d...

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Spectrometer from a drone

by sylvainbonhommeau 11 days ago | 5 | 251 | 0

Hi guys and congrats on this project, it's amazing! I'd like to know if it would be possible to t...

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Capacitive Discharge Welder

by kinasmith 12 days ago | 5 | 222 | 2

I've been working on this Mostly unrelated and relatively dangerous project over the past week ...

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Quantum Yield of Rhodamine B in Ethanol (Gain Corrected Spectra)

by dhaffnersr 12 days ago | 1 | 166 | 0

Rhodamine B is a chemical compound and a dye Abstract Rhodamine B is a chemical compound and a ...

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Using a Rhodamine B standard to correct some past research mistakes...

by dhaffnersr 24 days ago | 8 | 234 | 0

I was going to post a new research note on a Rhodamine B concentration study yesterday and decide...

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Mini spectrophotometer - how does this deviate from the Beer-Lambert law?

by FoxClass about 1 month ago | 7 | 274 | 0

I'm looking at using the mini foldable spectrophotometer (from Public Lab) to monitor qualitative...

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Plab v2.5 (upgrade 2) Comparison Spectra to SpexFluoroMax Spectrometer

by dhaffnersr about 1 month ago | 28 | 536 | 0

Abstract This was the original spectrometer from Plab's spectrometer kit that inspired me to mod...

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WebValley 2016: improved compact spectrometer

by cristoforetti about 1 month ago | 7 | 552 | 0

What I want to do Second post about the development of a portable spectrometer to be used outdoo...

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More research on "spectrometer" »

Title Last edited Edits Likes
How To Obtain Transmittance/ Absorbance Spectra 6 days ago by dhaffnersr 13 0
Desktop Spectrometry Kit 3.0 about 1 month ago by abdul 47 14
Effects of UV Radiation on Glass, Quartz and Plastic using UV LED and UV Laser Pointer about 1 month ago by dhaffnersr 2 0
Which Cuvettes for Spectroscopy are optically the best suited for the job - Part ll about 1 month ago by dhaffnersr 1 0
Which Cuvettes for Spectroscopy are optically the best suited for the job? about 1 month ago by dhaffnersr 5 0
Oil Testing Kit 3 months ago by warren 131 12
Oil Testing Kit Beta 3 months ago by warren 67 9
DIY Oil Testing Advocacy 3 months ago by warren 14 1
DIY Oil Testing: Community 3 months ago by warren 14 2
DIY Oil Testing Questions 3 months ago by warren 25 2
Spectral Workbench Operations 3 months ago by warren 14 2
DIY Oil Testing 5 months ago by warren 18 1
Oil Testing Workshop 4: Analyzing and Sharing 5 months ago by warren 4 1
Oil Testing Workshop 1: Design an experiment 5 months ago by warren 12 2
DIY Oil Testing Tools 6 months ago by warren 7 1
Oil Testing Kit Literature 7 months ago by warren 9 9
Oil Testing Kit Construction 8 months ago by warren 10 0
Refinery Watching 8 months ago by warren 18 4
Smartphone spectrometer 10 months ago by tonyc 27 7
Desktop Spectrometer 3.0 parts list about 1 year ago by warren 3 6
Ottawa over 1 year ago by warren 2 6
Spectrometry Sampling over 1 year ago by OpenSourceScience 22 5
Pesticide Detection Methods Development over 1 year ago by silverhammer 27 6
The Homebrew Sensing Project almost 2 years ago by Becki 5 0
Spectrometer History about 2 years ago by mathew 4 0
Oil Testing Kit Illustrations about 2 years ago by warren 3 0
spectrometer-media about 2 years ago by warren 2 2
How to make a homemade spectrophotometer about 2 years ago by Haripriya 3 3
Spectrometer Curriculum over 2 years ago by bicwood 25 5
Spectrometry health applications about 3 years ago by warren 10 1

Desktop Spectrometry Kit v3

The standard -- plugs into your laptop

Build one Buy one

Foldable Mini-Spectrometer

Cheap, easy, starter version for smartphones and webcams

Build one Buy one

Public Lab's Do-It-Yourself spectrometry kits are being community-designed to analyze pollutants -- join in and help improve them!

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.


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