Desktop Spectrometry Kit v3

The standard -- plugs into your laptop

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Smartphone Spectrometer

Rigid plastic version which attaches to your smartphone

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Foldable Mini-Spectrometer

Cheap, easy, starter version for smartphones and webcams

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**** ##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: [![sky.png](]( **** ##Types of spectrometry There are different ways to use spectrometers, and the key difference is how you illuminate your sample. ###Fluorescence This project focuses on fluorescence spectrometry in order to [identify oil pollution samples](/wiki/oil-testing-kit), 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 »](/wiki/oil-testing-kit) **** [![IMG_20140722_230007_2.jpg](]( ###Emission 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](/wiki/refinery-watching), for example at gas refineries in Louisiana, to try to detect heavy metals. [image of refinery watching] ###Absorption 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: * [algae](/tag/algae) * [wine](/tag/wine) * [beer](/tag/beer) * [coffee](/tag/coffee) * [tomatoes](/tag/tomatoes) **** ##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](/wiki/desktop-spectrometry-kit-3-0), 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](/wiki/spectral-workbench) ##Upgrades 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 **** [![Screen_Shot_2014-07-24_at_3.44.28_PM.png](]( ##Software 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](/wiki/spectral-workbench-api) * offline mode * read more [in the documentation](/wiki/spectral-workbench) **** ###FAQ Frequently Asked Questions [can be found here »](/wiki/spectrometer-faq) ###Challenges 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](/tag/spectrometer). Some of the challenges that remain include: * easy auto-calibration of the device (see progress by @sreyanth) * easier and more consistent [sample preparation methods](/wiki/spectrometry-sampling) * additional challenges specific to oil identification can be found on the [Oil Testing Kit page](/wiki/oil-testing-kit) **** ###Other uses While many of us have focused on [identifying oil pollution with fluorescence spectrometry](/wiki/oil-testing-kit), there are many other uses for cheap, open source spectrometers, and many other ways to use a spectrometer. ###Kickstarter 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](/notes/Shannon/01-14-2014/public-lab-launches-new-initiative-to-affordably-detect-pollutants-with-open-hardware-tools) is made possible in part by the generous support of the [John S. and James L. Knight Foundation](, Knight News Challenge: Health. [![knight-logo](/sites/default/files/kflogo-300x.jpg)](