About this project
Update: So many people have asked: we ARE doing an iOS version, having passed the threshold weeks ago!
A spectrometer may not sound like what you wanted for your birthday, but it's a ubiquitous tool for scientists to identify unknown materials, like oil spill residue or coal tar in urban waterways. But they cost thousands of dollars and are hard to use -- so we've designed our own.
This open hardware kit costs only $35, but has a range of more than 400-900 nanometers, and a resolution of as high as 3 nm. A spectrometer is essentially a tool to measure the colors absorbed by a material. You can construct this one yourself from a piece of a DVD-R, black paper, a conduit box, and an HD USB webcam.
We've also created open source software (spectralworkbench.org) to collect, analyze, compare, and share calibrated spectral data. We've even made an experimental version which converts your cellphone into a spectrometer (see rewards -- now with iOS in addition to Android)!
Public Lab community members have used this new tool to identify dyes in "free and clear" laundry detergent, to test grow lamps, and to analyze wines.
Now we need your help in collecting data to build a Wikipedia-style library of open source spectra, and to refine and improve sample collection and analysis techniques. We imagine a kind of "SHAZAM for materials" which can help to investigate chemical spills, diagnose crop diseases, identify contaminants in household products, and even analyze olive oil, coffee, and homebrew beer.
Public Lab is an open community (join now!) which investigates environmental issues with DIY tools. You might have heard about our first big project to document the BP oil spill using aerial photos from kites and balloons and our balloon mapping kits Kickstarter. Since then we've been working on new ways to ID contamination on the cheap. We hope you'll join us in taking the next step!
The mobile phone spectrometers and the $35 "desktop kit" have no built-in light source, or stand, so you'll have to get your own (hardware store! Or use a tabletop microphone stand!). This is partially because it's adaptable for reflectance, transmissive, or fluorescence spectroscopy, which some folks have been asking about (we'll post more on this soon!). So you might want to use it with a portable light, sunlight (http://spectralworkbench.org/tag/sunlight), a UV light (http://spectralworkbench.org/sets/show/15) or a laser (http://publiclaboratory.org/notes/warren/7-26-2012/oil-residue-preparation-spectroscopy).
A lot of people are asking exactly what you can do with your spectrometer. First of all, check http://SpectralWorkbench.org for what people have already done. Second, exploring these questions is why we're launching this project -- we're hoping you all will help explore new uses, refine and improve how it's used in open source style. So the answer is -- maybe! Probably! But the point is that you can use it to investigate, demonstrate, prove or disprove exactly that question! Just be sure to share what you find with everyone else -- there are already active discussion underway at http://PublicLaboratory.org's mailing list.
Also! We've created a wiki page at the Public Lab site to collect, share, critique, and test different applications. So check it out and contribute what you know: http://publiclaboratory.org/wiki/spectral-analysis
Basically the desktop version is JUST a spectrometer, and it's a DIY kit; you have to assemble everything yourself. The countertop model is mostly assembled, precalibrated, and comes with a dimmable light source and a sample dish, and has a stand. Both come with the same HD USB camera.
What's the difference between the papercraft spectrometer and the $65 "backpack" one? And what the heck is a "backpack" spectrometer?
The "backpack" model -- which clips to your mobile phone like a tiny "backpack" (some people thought it was as big as a backpack!) -- is going to be a rigid design which is durable enough to take outside and do fieldwork with. We're going to try to get it injection molded or 3d printed. By contrast, the fold-up spectrometer will definitely work, but probably won't be durable enough that you can throw it in the bottom of your backpack and go on a hike. A prototype of the "backpack" model is the lead image, above -- see, it's small! You'll be able to adhere it to your phone, or to a rigid phone case if you don't want to ruin your phone :-) Both mobile versions will be limited to visible light -- ~400-700 nanometers, unless of course you're willing to open up and remove the filter from your phone's camera!
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