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
shubham "Simply use some nailpolish remover (from your sister's cabinet :P) to remove all the dye within seconds. You can make reflective as well as clear t..." | Read more » about 8 years ago
viechdokter "@warren: I just had a look at an old spectrum CSV file of yours (3 years ago): https://spectralworkbench.org/spectrums/481 There it was unscaled ..." | Read more » about 8 years ago
warren "I went ahead and created a specific issue for native 8-bit storage: https://github.com/publiclab/spectral-workbench.js/issues/18 As well as outlin..." | Read more » about 8 years ago
viechdokter "Talking about hung-up scripts, it often is a pain in the neck to login to SBW. "Do you trust this site with your identity?" "Yes" "You must login t..." | Read more » about 8 years ago
stoft "It's ok to have a 'scaled' data file -- but ONLY if that file is clearly identified as such ... like /SpectrumData-SCALED_20160420.csv or /Spectru..." | Read more » about 8 years ago
warren "Hi, all -- 2.55 is definitely related to the 0-255 value. The code that generates the CSV is here: https://github.com/publiclab/spectral-workbench..." | Read more » about 8 years ago
viechdokter "I could re-scale but ... when everybody here gets the same minimum 2.55 increments here and you want reproducible spectral data then everyone shoul..." | Read more » about 8 years ago
stoft "Hmmm, well the RAW data should have the same scale units which would be unsigned 8-bit integer from 000 to 255 -- so the Y axis should show noise h..." | Read more » about 8 years ago
viechdokter "I took the data from the CSV files that Spectral Workbench provides with my spectra. I had a look at one of dhaffners spectrum CSV files and see th..." | Read more » about 8 years ago
stoft "Well, except there's still a problem with the plot. The smallest increment looks to be '4 steps' per scale units of '10'. Either there was some mul..." | Read more » about 8 years ago
viechdokter "Okay, here I combined the 4 channel max/min-difference curves in one diagram so they have the same vertical scale now: And here the combined dat..." | Read more » about 8 years ago
viechdokter "Talking about bits and quantization: I also noticed that certain values (2.55 and multiples thereof like 5.1, 7.65 ...) appear in every spectrum's ..." | Read more » about 8 years ago
stoft "Yes, it's called quantization; the camera only has 8-bits and the scale of the two plots is likely about 3-5x different. Take a look at the 'red' p..." | Read more » about 8 years ago
warren "Hmm, very interesting -- without vertical scale its hard to say though - I believe the "plateaus" on the "average curve" are artifacts of the preci..." | Read more » about 8 years ago
viechdokter "@warren:They would be low-noise green if you average them. ;-) @stoft: BTW, I noticed that curves that were averaged over two or more channels l..." | Read more » about 8 years ago
warren "Would he be low-noise green? :-) I'd also love to see them plotted on the same graph, maybe with the graph lines themselves in appropriate colors...." | Read more » about 8 years ago
viechdokter "Yeah, I think I could do it. Hmh, I must admit that I only pretty recently started to use Excel-like programs at all. To be honest, your research n..." | Read more » about 8 years ago
stoft "I believe both Excel and Quattro Pro provide for multiple plots. I suspect your's may as well -- in Quattro it's under the specialty xy plotting. I..." | Read more » about 8 years ago
viechdokter "Yes, you are right. I, too, like comparable curves better. I used LibreOffice, a kind of public domain "Excel". It plots diagrams automatically and..." | Read more » about 8 years ago
stoft "Not to worry, I too find bits to revise after I publish; what counts is fixing the details as they appear. One thought on visualization. When I do ..." | Read more » about 8 years ago
viechdokter "@stoft : sorry I had to revise the research note as there was a big mistake in the red curve. I exchanged it with the new revised red curve and now..." | Read more » about 8 years ago
stoft "Right. That's the Bayer filter pattern which sits in front of the imager chip and gives double the signal sensitivity for Green -- a simulation of ..." | Read more » about 8 years ago
viechdokter "@stoft : RGGB like in this picture? " | Read more » about 8 years ago
stoft "Good observations! Remember that the AGC is likley based on the sum total over the entire image; not per pixel. If there were independent AGC per c..." | Read more » about 8 years ago