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All Over But the Funding: Open Hardware Spectrometer Kit 62

Posted by timothy
from the what-is-the-exact-color-of-your-van? dept.
New submitter mybluevan writes "The Public Laboratory for Open Technology and Science is putting together an open hardware spectrometer kit on Kickstarter. The kits are built using an HD webcam, discarded DVD, and a couple other odd bits. They've also put together a kit for your smart phone and open-source software for desktop, Android, and iOS. Need to analyze the contents of your coffee, the output of your new grow lights, or a distant star on a budget? Just build your own spectrometer, or pick up the limited edition steampunk version." Besides making cool hardware, they'd like 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."
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All Over But the Funding: Open Hardware Spectrometer Kit

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  • Finally! (Score:5, Funny)

    by ColdWetDog (752185) on Friday September 21, 2012 @11:46PM (#41418853) Homepage

    A use for all those Windows ME disks!

    (You need a DVD as a diffraction grating.)

  • by billstewart (78916) on Friday September 21, 2012 @11:53PM (#41418881) Journal

    Ok, they've got a few days left, but they've currently got $72000 vs. their $10000 goal. Cool project, interesting applications.

    (But since we're talking Kickstarter here, I'd like to put in a plug for the Drip Clip kickstarter. They've designed a small drip-counter to be used for measuring medicine in intravenous bags, especially for applications like disasters, third-world hospitals, and the like. The prototype used Arduinos and baling wire, but the production version is going to be manufactured plastic with a simple count-down display on it.

    • by SomePgmr (2021234)

      I pitched in (and hope to get one of these), after having done one of the online instructions for a very rough looking one. It seems like the sort of thing that will net me hours of goofing off for very little money. ;)

      That Drip Clip sounds pretty cool, though it looks like it's IndieGoGo, not Kickstarter: http://www.indiegogo.com/shiftlabs [indiegogo.com]

      Unfortunately, $75 is a bit out of my funding range. Otherwise it'd be a nice little sensor to play with.

    • Re: (Score:3, Interesting)

      by mybluevan (2736301)
      They've got an interesting stretch goal though: "if we get to $100,000 -- a 'stretch goal'. In the spirit of enabling open collaboration we'd like to make it possible for people to make their own Spectral Workbench-based apps". I'm thinking a Spectral App Platform API would be pretty sweet. "Imagine a "Spectral App Store" where wine enthusiasts can develop their own testing suite for wines, gardeners for grow lamps, and coffee connoisseurs for coffee -- each looking for specific wavelengths or patterns *spe
  • Pretty cool ... (Score:5, Interesting)

    by RockDoctor (15477) on Friday September 21, 2012 @11:55PM (#41418887) Journal
    That's an interesting combination of technologies and materials. The basic idea should be workable, but how workable they'd be for material identification given the prevalences of IR filters on (consumer grade) CCD sensors and their relatively low sensitivity ....Identifying spectral lines on a 10-bit sensor is difficult enough. Trying to do it on the 7-8 bits that you get from a (consumer grade) sensor ... is going to be more difficult.

    But ... that's an interesting idea. I think that's worth a six-pack worth of funding.

    Did I get a first post? Are the trolls and the GNAA spammers asleep? Or, preferably, dieing slowly?

    • Re:Pretty cool ... (Score:5, Informative)

      by dns_server (696283) on Saturday September 22, 2012 @12:31AM (#41418997)

      One of the steps of building the kit is removing the IR filter from the webcam.

    • Re:Pretty cool ... (Score:5, Informative)

      by thegarbz (1787294) on Saturday September 22, 2012 @03:19AM (#41419521)

      I have converted consumer junk to remove IR sensors on many devices from simple webcams to high end DSLRs. It is simple.

      The hardest part about the process on cameras is working with tiny ribbon cables and sourcing replacement optics if you wish the resulting camera to operate again (since removing the filter completely will result in your camera becoming nearsighted.

      Neither of these are a problem with webcams, and the only issue you're likely to have is that some webcams have their filter glued onto the CCD rather than just placed on and retained with a small amount of pressure from the case.

    • by hardie (716254)

      Actually, it IS workable. Check out the link.

    • Re:Pretty cool ... (Score:4, Insightful)

      by drooling-dog (189103) on Saturday September 22, 2012 @09:45AM (#41420853)

      Trying to do it on the 7-8 bits that you get from a (consumer grade) sensor ... is going to be more difficult.

      True, but if you're imaging the spectrum in two dimensions and summing/averaging vertically (over columns), you'll improve your Signal/Noise ratio considerably (by the square root of the number of vertical pixels, ideally). It wouldn't surprise me if the results were quite decent.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      The bit depth of the sensor is more or less irrelevant. Spectral accuracy is a function of their diffraction grating and the size of the sensor: it's a spatial effect, not a detection/encoding one.

      The bit depth does matter for sensitivity and dynamic range. For sensitivity, the dark noise of the sensor is also important, since you can effectively average for a very long time.

  • by Anonymous Coward on Friday September 21, 2012 @11:57PM (#41418897)

    Back when I was in University in 2001 (U Waterloo - Independent Studies) one of the guys found a spectrometer for sale at the weekly physical plant surplus sale for fifty bucks so he just set it up in the IS lounge (which was in the middle of the Psych building) so people could come in and analyze whatever they wanted. It was great for inviting hippies in to charge up crystals with very specific wavelengths to increase harmonic resonance.

  • I freeken love this. (Score:4, Informative)

    by Anonymous Coward on Saturday September 22, 2012 @01:11AM (#41419105)

    I did my PhD on a topic that involved building some gear related to spectroscopy. A good deal of my work involved cludging together optical parts from seemingly unrelated sources. As such I just love this sort of thing. Unfortunately I have to agree with the above commenter that the precision is just not going to be good enough from a webcam for real chemometric measurement. However with a little more investment the precision could be improved. The real difficulty will come from the need to calibrate the thing. You need to know exactly where each wavelength of interest is centred ** exactly** on the sensor at the time of measurement and this is not a trivial task. Unfortunately proper calibration is so often just not achieved... and that's not even beginning to consider the issues of background/ stay light, Johnson noise etc. I suppose this design could be used for crude detection like the article says rofl.

    • Re: (Score:3, Interesting)

      by Anonymous Coward

      What is interesting about talking to researchers about spectrometers, is there is quite a diverse spread of priorities and needs depending on what they are doing. The work I did required a significant amount of time calibrating several aspects of the spectrometer (intensity and response calibration being typically much more annoying than just the position of lines). I would discuss calibration methods with other researchers at conferences, and be thinking, "How primitive, you would barely be able pass an

      • Re: (Score:3, Informative)

        by Anonymous Coward

        This is the same AC that you replied to. Yeah, every time one little part got changed on our $100,000 units the whole thing had to be re-calibrated for response factors. Then they would break down all the doggam time. Fibres would break or a microchip might come unseated and I wasn't allowed to touch the insides. Not to mention the cost of the reference reflectance tiles being a little bit more than the average bathroom ceramic.

        As for the crackpots and bad calibrations, I thought my head would fall off from

        • by Anonymous Coward

          (AC you replied to... AC #2, or second ... shut up, I'm lazy about registering...)

          We basically did full calibrations in the morning and evening of every day we ran, assuming we didn't change the narrow spectral range we were looking at. We wanted to be sure no one bumped the spectrometer or fibers, and that it wasn't affected by changing temperature, or the experiment itself (pulsed plasma experiments kind of wreck havoc on equipment). But if we needed to change what wavelengths it was looking at, that

    • by photonic (584757) on Saturday September 22, 2012 @07:02AM (#41420053)
      Optics guy here too. I don't know a lot about spectroscopy, but I had to assemble a spectrometer for my thesis project. It was a pretty fancy imaging spectrometer (main element was a concave mirror and grating combined in one) and used a LN-cooled CCD as the sensor. This was not cheap stuff (~5000eu for the spectrometer and probably > 20000eu for the camera), but the operating principle is exactly the same as the DVD + webcam. The resolution was limited to around 1 nm due to the input slit, not sure if they could improve things by using a slit in this home-built device. I had to calibrate it from scratch, which was actually pretty easy: I borrowed some spectral lamps from the 1st year lab course and also used a HeNe-laser we had laying around. Choose a few of the big lines (which should all be known to better than 1 nm) and for each write down the pixel position of the line on the CCD. Perform low order (e.g. quadratic) polynomial fit and you are done calibrating. I don't know if there are some cheap spectral lamps that you could use at home, there is at least the yellow lines from the Sodium (?) street lightning. I agree with others that the resolution of these home built devices is probably too low to identify materials, but it is for sure a fun project.
      • For a homebrew project, you're going to want to calibrate it using things you have easy access to. Things that are found in nature, perhaps. There must be a clever way to avoid having to borrow or obtain a lab-grade arc lamp. Perhaps using a CFL and the right filtering? I'm not sure how monochromatic each of the phosphors are...

        Maybe accurate calibration isn't necessary, and just using the peak wavelengths from the sun and a halogen lamp would be sufficient to get a rough calibration using wein's, assu

      • by Anonymous Coward

        Sometimes the bottleneck is elsewhere, but typically in my experience with spectrometers, the limit to your resolution is the camera or the grating... and not necessarily in the most obvious sense. In many cases it doesn't take much camera resolution to the point smaller pixels won't help (I've used enough high end spectrometers where their 640x480 sensor had more pixels than was useful). Two quick ways to increase resolution would be to narrow the slit and to increase the length the light goes to give it

    • by Atraxen (790188)

      True - but for a homebrew quality spectrometer, using a green laser pointer can at least provide a two-point calibration (the 1064 and 532 lines - at least for cheap laser pointers with garbage IR blocking filters - www.nist.gov/customcf/get_pdf.cfm?pub_id=906138). You could probably get clever and determine the central lambda-max for the red and blue diode lasers but using the distance between 0th, 1st, and 2nd order diffraction spots off a grazing/dvd to get an ok value for it - but boy, these calibratio

      • by Anonymous Coward

        Lasers would be pretty good for a strong, known light source for rough calibration (10 nm... maybe 1 nm resolution). But, along with LEDs, their wavelength and spectra are not as stable and consistent as some people think. I've used LEDs to calibrate equipment before, although that was only after measuring and determining their spectra with another spectrometer that was calibrated from other sources. Sometimes even LEDs within the same batch varied by 10-20 nm for their peaks, which is good if you want m

    • Some of the people that have early prototypes are claiming 1nm precision. They've mainly been using CFLs for calibration because of the variety of consistent spectra points and how common they are. Not lab grade, sure, but decent enough for home use.
    • by dbIII (701233) on Saturday September 22, 2012 @11:21AM (#41421615)
      As late as the 1990s I used a portable optical spectroscope with a battery to strike an arc and a book full of photos showing where the lines should be for specific elements for alloy identification. I only used it a couple of times and didn't get the hang of it, but apparently some people got useful results from it to the point of estimating percentages of elements instead of just seeing if they were present.
  • "Open hardware" "limited edition" ... I'm pretty sure someone doesn't understand how this works. :)

    • by jywarren (2718221)
      The brass-and-wood "steampunk" version is limited edition, but only limited in that we're only selling 5 pre-built spectrometers. The designs are already online for most of these models and based on the early build photos and bill of materials you can build your own (under the CERN Open Hardware License). So it is open hardware -- have fun!
  • by Anonymous Coward on Saturday September 22, 2012 @01:55AM (#41419237)

    Lots of people have been working in this field. The most impressive results are achieved by the astronomy community. link [stargazing.net] It is possible to produce a home made spectrometer that gets useful results. Some of these are capable of resolution sufficient to identify chemicals. These are sophisticated and often use a peltier cell to cool the CCD in order to reduce noise. link [fzu.cz]

    I did a project whose aim was to produce a cheap spectrometer to match paint colors. link [conestogac.on.ca] The problems I found were:

    1. Cheap webcams are quite noisy
    2. Cheap webcams are not at all linear
    3. For dark colors, sensitivity is a big problem
    4. The spectrum of the light source varies depending on which angle you view it from.
    5. Organizing the data is perhaps the biggest problem of all

    My own engineering trade-off was sensitivity vs. resolution. To get spectra for dark colored paints, I widened the slit which reduced resolution. That, as far as I could tell, was reasonable because I wasn't trying to identify chemicals and the spectra from paints weren't particularly sharp.

    The folks in TFA have a site where people can upload spectra. That's fine but a huge database of spectra is not too useful. The spectra have to be organized somehow. Here's an example [utexas.edu]. In fact the problem can be quite daunting [boingboing.net]

    • by Anonymous Coward

      These are sophisticated and often use a peltier cell to cool the CCD in order to reduce noise.

      It's really neat, but I wouldn't call it sophisticated. Thermal noise is randomness. Less heat, less noise. Up to a point, you could use ice or a cold climate to accomplish the same thing as a peltier. Or go further than a peltier and use cryogenic liquids and really maximize the SnR. (It's all slightly impractical.)

      I've been playing around with an idea on the same topic as this story, but I haven't heard anyone else mention it before. Building a spectroscope using LEDs. Instead of emitting light, they're u

      • by qvatch (576224)
        LEDs will still have a pretty broad spectral response so you'd have overlap, and need quite a bit of gain. Try one of the taos colour sensing chips, those do RGB+all with programmable gain and digital output, it'll make the project pretty simple and much more repeatable. you can also do one clear NIR phototransistor with selectable filters for colours. That'd be manageable. For my project, I am using, currently, a clear phototransistor and illuminating the target with a specific LED colour. I think someon
    • by drinkypoo (153816)

      These are sophisticated and often use a peltier cell to cool the CCD in order to reduce noise

      OK, the peltier is going to cost ten bucks and need a twelve volt supply. Not a big deal. I bet they charge a lot for that though :)

  • by thegarbz (1787294) on Saturday September 22, 2012 @03:23AM (#41419537)

    Really the very first picture they showed of the spectra and the resulting plot on the very top of their kickstarter page has the graph backwards compared to the visible spectra.

    With such an epic facepalm I'm surprised they know what a spectrometer is.

    • by Anonymous Coward

      Backwards? You mean because light always increases wavelength from left to right?!
      Maybe it is just in an unconventional "direction" because the sensor captures it that way?

      epic facepalm indeed

      • by thegarbz (1787294)

        No I mean backwards in that the image of the spectra doesn't line up with the actual spectra immediately underneath it. It doesn't matter which way it runs, but one would think if you're advertising a system which gives you a spectrum from an image you'd at least line them up so they both face the same way.

  • Wake me up when they get to a homebrew ultrasound imager, or something a little more interesting. Or at least a spectrometer that works off lazer burn at a distance and built into a portable point-and-shoot unit you can walk around with.
  • Cringe-worthy (Score:3, Informative)

    by threeplustwo (1733970) on Saturday September 22, 2012 @06:23AM (#41419951)
    I don't want to sound all negative here, but... I don't have a choice, do I? A visible light spectrophotometer will not "detect toxins", no matter how much you try to make it open-source or crowd-sourced. The very concept of identifying compounds by visible light absorbance is very much flawed. Thing is, *most* molecules will not absorb visible or near UV light in a way that is specific enough. Real Chemists (TM) traditionally use the so-called IR fingerprint region for this purpose. This region is from approx. 700 to 1500 cm-1 (about 6 to 20 uM - that is 6000 to 20000 nanometers). A special detector is needed for these wavelengths. The one we have in our lab is cooled with LN2 and costs south of $15K. We also have a UV-Vis spectrophotometer, which has its own purpose. That purpose is not "identifying toxins", or analyzing any unknowns. Now, on to my next point. Identifying molecules is challenging, because they are very, very, very mindbogglingly small. Chemists have been grappling with this challenge for a long time. There are many spectrometric methods out there, including IR and UV-Vis (briefly discussed above), near-IR (900 to ~1800 nm, useful for *some* fingerprinting), and NMR (60-1000 MHz, very informative, bit needs a BIG magnet). Spectral data for many molecules of interest has been compiled into readily accessible databases, and is easily accessible. Some of the databases are proprietary/pay-per-view: https://ftirsearch.com/features/libraries/sea407.htm [ftirsearch.com] Some are semi-public: http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi [aist.go.jp] And some are government/public: http://webbook.nist.gov/chemistry/ [nist.gov] The people who started this project do not seem to grasp of the very basic concepts of chemistry, nor did they do any research on the subject. Reading a Wikipedia article on UV-Vis would have been a good start. What is even more disconcerting is that the fundraising effort behind this cardboard spectroscope has been a success. One just has to hope that nobody buys this to screen their food for "toxins", or to teach their kids chemistry.
    • Re: (Score:3, Informative)

      by jywarren (2718221)
      Hey threeplustwo -- actually there is pretty good literature on laser fluorescence spectroscopy of polyaromatic hydrocarbons in the near-UV to visible range, you should check out some of the Public Lab research notes on the subject: http://publiclaboratory.org/notes/warren/7-18-2012/fluorescence-oil-spill-residue-diverse-spectrometer-use [publiclaboratory.org] with longer exposures we are able to get a clean read on the fluorescing spectrum. And even in the shorter term (before these harder uses are better developed and more rig
      • Sure, fluorescence spectrometry is pretty useful. So is UV-Vis. In my lab, I use the latter to estimate the size of gold nanoparticles we are making (there, I said the "nano" word!). We use a cheap-ish Lambda XLS+ machine built by Perkin-Elmer. However, there is a very big gap between observing fluorescence of PAHs (not really possible with their specific setup) and the sweeping claim that they "...imagine a kind of 'SHAZAM for materials' which can help to investigate chemical spills, diagnose crop diseas
    • by gillbates (106458)

      It seems you're burning a straw man. The project goals were not to "detect toxins" in the general sense, but to detect the presence of certain chemicals with a well-known, easily identifiable spectrum.

      And your bit about molecules being "mind bogglingly small" is irrelevant. Such a limitation didn't prevent 18th century chemists from discovering the elements, and is not likely to pose a problem for the spectrometry crowd, either.

      Naturally, it is easier to detect the spectrum of something for which you

      • Read the TFA, if you have not yet.

        "We are working on a cheap version which we hope to use to identify oil contamination in water and soil, as well as a range of other possible toxins."

        It is in the first paragraph, right at the top of the page. I did not invent it. Also, they are trying to make an absorbance spectrometer. It has nothing to do with planets or astronomy.

        I would not call their goals "lackluster" either. I wish I had something like that in my lab. Problem is, the execution is very poor. Th

  • Disclaimer: I'm no expert in spectroscopy.

    Would it be possible to estimate the blood's sugar content with this kit?

    It is possible non-invasively with Raman spectroscopy in the infrared:
    http://www.popsci.com/technology/article/2010-08/mit-glucose-meter-checks-blood-sugar-levels-painless-ir-light [popsci.com]

    The usual blood glucose meters have errors of up to 50% in the reading. And they still require those expensive analysis strips.
    If a home blood glucose measurement would be possible with one of those kits (even if you

    • Re: (Score:3, Informative)

      by threeplustwo (1733970)
      Non-invasive glucose measurement is one of the holy grails of portable spectrometer design. As it happens, it is most practical using NIR and IR. There are products that will be on the market soon. The kit from TFA won't do it, of course. Spectral resolution is too low, and it looks at all the wrong wavelengths.
  • by Anonymous Coward

    this is awesome! I may not be able to support papers to chemistry journals with it, but for teaching people how different colors of light split up into wavelengths with a prism, this is perfect. I've spent some time showing people how to use spectrographs (the black tubes) to see wavelengths of flourescent lights and LEDs and it's kind of a pain to teach them how to see in the edges of the tube. However, with this kit, everything's already aligned and I can bring the pix into a computer to show a scale d

  • So... Can I use this to determine the alpha and beta acid levels in my homegrown hops?

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