Spectrometry
activity:spectrometry

The Public Lab spectrometry project is an open source community effort to develop low-cost spectrometers for a range of purposes. All open spectrometry hardware and software efforts are welcome here! **Join in by:** * Learning [what spectrometry is](#Whats+spectrometry) * Reading about goals and [asking great questions](#Frequently+Asked+Questions) * Building a basic spectrometer using [one of our starter kits](#Starter+Kits) * Trying (and critiquing) our [community-made how-to guides](#Activities) and posting your own * Building on others’ work; hack and remix the kits to refine and expand them * [Share your upgrades](#Upgrades) for others to try -- and perhaps for inclusion in an upcoming starter kit release or add-on kit **** ## Starter Kits Public Lab’s Kits initiative offers several starter kits, including many of the basic components, and instructions for constructing a basic visible light spectrometer. The point of the kits is to provide a shared reference design for building experimental setups onto. Lego Spectrometer Kit Our most recent kit, incorporating community improvements while balancing low cost and ease of construction. Choose between webcam and Raspberry Pi camera versions and build attachments width standard Lego connectors. Build one Buy one Papercraft Spectrometry Intro Kit A $9 paper spectrometer which you can attach to a smartphone or webcam. It’s made of paper to reduce cost and complexity, and is mainly intended as an “introductory” or educational kit. The flat design can be printed on a laser printer or photocopied to make more. Build one Buy one **** ## Activities This is a list of community-generated guides for specific applications using your spectrometry setup (either a [starter kit](#Starter+Kits) or a [modded design](#Upgrades)). These [activities can be categorized](https://publiclab.org/wiki/activity-categories), and some may be more reproduced -- or reproducible -- than others. Try them out to build your skills, and help improve them by leaving comments. Together, we can repeat and refine the activities into experiments. > **Note:** If you are working on an **urgent issue** such as a threat to your or someone else’s health, please know that these techniques may not be ready for your use; it's possible that they never will be. [Read more here](/notes/gretchengehrke/09-29-2016/common-low-cost-technique-limitations) ### Activity grid [activities:spectrometry] **** ## Upgrades Have you added to your starter kit, improved it, or redesigned it? Show others how to take it to the next level by posting a build guide here: [upgrades:spectrometry] Add your upgrade guide here Request or propose an upgrade _Mods should include a parts list and a step-by-step construction guide with photo documentation. See an example._ **** ## Challenges We're working to refine and improve DIY spectrometry on a number of fronts; here, take a look at the leading challenges we're hoping to solve, and post your own. For now, we're using the Q&A feature, so just click "Ask a question" to post your own challenge. Be sure to add: * constraints: expense, complexity * goals: performance, use cases [questions:spectrometry-challenge] **** ## Builds There’s a lot going on in open source spectrometry -- if you’ve developed another open source design you’d like to show others how to construct, post it here! * [RamanPi](https://hackaday.io/project/1279-ramanpi-raman-spectrometer) * [Hackteria “drop”-style spectrometers](https://publiclab.org/notes/gaudi/04-03-2014/diy-micro-volume-spectrophotometer) / [DIY NanoDrop on Hackteria.org](http://hackteria.org/wiki/index.php/DIY_NanoDrop) * _Add yours here_ ##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, in nanometers of wavelength) and intensity (vertical axis) below: [![sky.png](https://i.publiclab.org/system/images/photos/000/005/455/original/sky.png)](https://spectralworkbench.org/analyze/spectrum/19882) > Needed: overview of spectra, calibration, units, comparison, and fluorescence/absorption. Please edit this page or link to a resource, potentially [the Wikipedia page](https://en.wikipedia.org/wiki/Spectroscopy), although that's quite full of technical jargon. ## Software Spectral data can be analyzed with https://spectralworkbench.org to create spectra plots, find centers of emissions plots, and find similar spectra. Data also can be exported in various formats (JSON, CSV, XML) for further analysis and visualization. ## How does this compare to a lab instrument? The [Desktop Spectrometry Starter Kit](/wiki/desktop-spectrometry-kit-3-0) is only one part in an experimental setup, and the following shows where it fits in an overall diagram of a lab spectrometric setup: [![tmp_31873-IMG_20161027_101601_2-79757779.jpg](https://publiclab.org/system/images/photos/000/018/635/large/tmp_31873-IMG_20161027_101601_2-79757779.jpg)](https://publiclab.org/system/images/photos/000/018/635/original/tmp_31873-IMG_20161027_101601_2-79757779.jpg) [![tmp_31873-IMG_20161027_095939_2-108076392.jpg](https://publiclab.org/system/images/photos/000/018/636/large/tmp_31873-IMG_20161027_095939_2-108076392.jpg)](https://publiclab.org/system/images/photos/000/018/636/original/tmp_31873-IMG_20161027_095939_2-108076392.jpg) There are many, many different types of spectrometry and spectrometers -- many don’t even measure light. Even among those that do, some detect light in the ultraviolet range, and others in the infrared range of light. The range of Public Lab spectrometers depends on the range of the commercially available cameras we attach them to (~400-700 nanometer wavelengths). A commercially available product with a slightly wider range (from 335 to 1000 nanometers) is [available from Cole Parmer](http://www.coleparmer.com/Product/Cole_Parmer_Visible_spectrophotometer_335_to_1000_nm_wavelength_range_analog_output/UX-83055-10). **** ## Frequently Asked Questions [questions:spectrometry] Note our previous Frequently Asked Questions page, which [can be found here »](/wiki/spectrometer-faq) -- please help port these into the new system, here!...


Author Comment Last activity Moderation
straylight "thanks ygzstc, that makes sense. I think that the approximation that relative intensity measured from the scope can be used in place of the log rel..." | Read more » almost 9 years ago
ygzstc "Yes the Beer-Lambert Law is based on -log(I/Io) but it's applicable for a single wavelength value. (https://en.wikipedia.org/wiki/Beer%E2%80%93Lamb..." | Read more » almost 9 years ago
warren "It's odd -- I see the graphs. Straylight, can you contact web@publiclab.org so we can figure out what's going on there? " | Read more » almost 9 years ago
straylight "Thanks for the question. My apologies that all of the graphs appear to have vanished (they have for me). Not sure why, maybe a hosting issue. Anyw..." | Read more » almost 9 years ago
anjohn12 "Quick question, I'm trying to do something similar for a school project. Shouldn't the absorbance of the sample be the negative log of the percent ..." | Read more » almost 9 years ago
DonV "I used Everclear 180 proof (ethanol) and the point of a sharp Exacto knife to both tease the layers apart and remove all the dye. The ethanol seem..." | Read more » almost 9 years ago
stoft "Great! Yes, little glitches do creep in but yes, this Solux corrected plot has a much better shape. I'm guessing the slight curve variation between..." | Read more » almost 9 years ago
warren "OK, a bunch of solved problems! figured out the height difference -- needs to be resolved, but I believe due to a bug, we were multiplying each p..." | Read more » almost 9 years ago
stoft "Jeff, thanks for pointing this out. I admit I do find the SWB terminology a bit overloaded and the user interface 'unexpected' as I'm not used to i..." | Read more » almost 9 years ago
warren "Hi, Dave - i noticed that https://spectralworkbench.org/spectrums/71409 has a linearCalibration operation - I think by mistake, as it's not a CFL. ..." | Read more » almost 9 years ago
warren "Also, regarding the unit precision, I've opened an issue at https://github.com/publiclab/spectral-workbench/issues/335 and would love your input on..." | Read more » almost 9 years ago
stoft "Understood; though independent checks and tests are still the best method to find hidden anomalies and overlooked issues. When you fix the glitch, ..." | Read more » almost 9 years ago
warren "Sorry, back online after a long weekend. Looks like there was just an error in my code -- i'm going to try and tackle some bugfixes today but after..." | Read more » almost 9 years ago
stoft "Just extracted the Slux4700K original data w/rgb and your gain-corr curve data from above, scaled the curves to eliminate that factor and plotted. ..." | Read more » almost 9 years ago
stoft "The CSV data files have poorly formatted data. The text of the files often looks like this: 206.809,2.55,2.5500000000000003,7.6499999999999995,2.55..." | Read more » almost 9 years ago
warren "Hi, Dave - I believe I was able to apply the correction by running the following line in the new Scripting tab: SpectralWorkbench.API.Core.useRefe..." | Read more » almost 9 years ago
warren "Thanks, Dave - I believe exports were fixed in https://github.com/publiclab/spectral-workbench/issues/322, which was only published just now with t..." | Read more » almost 9 years ago
stoft "Ok, I got a fresh copy of Chrome to work so here's a Solux 4700K spectrum which was callibrated with a 'CFL2700K' new cal data. https://spectralwor..." | Read more » almost 9 years ago
warren "Hi, Dave, thanks. I responded and split out a new issue with the calibration bug and added a couple questions. " | Read more » almost 9 years ago
stoft "Ok, just took a look, replied no, still broken. I cleared cache with no effect. I filed another bug report as I cannot even use the switch to a 'ne..." | Read more » almost 9 years ago
warren "Hi, Dave - I left some requests on your issue to try to reproduce the error you're seeing; did you see that? https://github.com/publiclab/spectral-..." | Read more » almost 9 years ago
stoft "Jeff, I was going to provide you with a fresh plot but unfortunately SWB still fails on Firefox -- same "left half only" spectrum with no visible d..." | Read more » almost 9 years ago
warren "Hi, Dave and @ygstcu - I have a version of the gain correction code loaded into a local copy of my code, and am testing it out. Dave, can you link ..." | Read more » almost 9 years ago
stoft "Jeff, pretty close. I'll try again, in case I'm not reading your code accurately.... 1 - Solux4700K_spec([nm(300:800),val(300:800)]) = the Mfg's s..." | Read more » almost 9 years ago