The Public Lab Desktop Spectrometry Kit 3.0 is the latest version of the spectrometer. Read more about [our Spectrometry program](/wiki/spectrometer), the [Oil Testing Kit](/wiki/oil-testing-kit) it is is a part of, or [the history of development](org/wiki/spectrometer-history).
Previous [versions 2 & 2.5 are here](http://publiclab.org/wiki/desktop-spectrometer-2).
###Parts List
[](https://i.publiclab.org/system/images/photos/000/008/649/original/IMG_20150116_183204-annot.png)
* two-piece custom box and fold-up pieces printed on [Neenah Sundance Eclipse Black Smooth 100 # paper](http://www.neenahpaper.com/FinePaper/ROYALSUNDANCEPapers).
Download the latest [print and cut files on github](https://github.com/publiclab/spectrometer3)
* "gumstick" webcam (from a laptop screen) with USB cable. datasheet: Spec_of_JDEPC-OV04_Ver_1.01.pdf
* 45 degree wooden (pine or ash) block, 3cm x 3cm x 3cm
* Masonite bench 1/4" (6mm) x 40mm x 235mm
* 50cm of 3/4" (2cm) width adhesive-backed loop fastener (Velcro-style)
* 25cm of 3/4" (2cm) width adhesive-backed hook fastener (Velcro-style)
* DVD-R
* photo emulsion printed slit 0.2mm wide printed on .004" acetate. [ files on github](https://github.com/publiclab/spectrometer3)
* 6 yard roll of [1/8" Thermoweb Supertape](http://www.thermowebonline.com/p/supertape-roll-%E2%80%A2-1-8-in) double sided tape. (3mm)
* printed assembly instructions (below)
###Using your spectrometer
Once you've assembled your spectrometer and are ready to use it, plug it in and visit [SpectralWorkbench.org](https://spectralworkbench.org) to begin recording data with it. The web-based software works in the **Chrome, Firefox and Opera browsers** on most computers and Android phones.
###(Peer) Support
Public Lab is not a corporation; we're an open community of DIY environmental science researchers which you have just joined! The best place to get help is the spectrometry mailing list; to join, sign up in the form to the left.
The spectrometry mailing list is made up of people like you, who are building and improving open source spectrometry techniques. Ask questions, look for help, and consider helping others too!
You can also post a question on this site; it helps to share some photos or screenshots of what you're trying to do:
[question:spectrometry]
###Resources
* [Common hardware issues](/wiki/spectral-workbench-help#hardware-troubleshooting)
* [Using the software](/wiki/spectral-workbench-usage) (including setup and software troubleshooting)
* [Frequently asked questions](/wiki/spectrometer-faq)
* [Background about the project](/tool/spectrometer)
* peer-contributed [research on open source spectrometry](/notes/spectrometer)
###Activities
here are the series of notes printed on the spectrometer. notes below by: @amysoyka, @straylight, @wagnerc4, @ygzstc, @cfastie, @stoft, & @Alex-McCarthy.
* lens focus: [/n/7226](/n/7226)
* grating angle: [/n/5964](/n/5964) [/n/5892](/n/5892)
* spectrometer development history: [/n/10691](/n/10691)
* removable slit cards: [/n/11246](/n/11246)
**This spectrometer design:**
* [/wiki/dsk](/wiki/dsk)
**Spectrometer development:**
* calibration: [/n/191]( /n/191)
* linearity: [/n/10476](/n/10476) [/n/6225](/n/6225)
**Activities:**
* oil testing: [/wiki/oil-testing-kit](/wiki/oil-testing-kit)
* detection of brightening agents in laundry: [/n/174](/n/174)
* pesticides: [/n/10015](/n/174)
* sugar in red wine: [/n/10955](/n/10955)
* olive oil adulterants: [/n/10382](/n/10382)
* milkfat concentration: [/n/10012](/n/10012)
* lycopene in tomatoes: [/n/9432](/n/9432)
* atmostpheric spectra: [/n/6168](/n/6168)
* concentration analysis (Beer’s Law): [/n/7475](/n/7475)
* flame spectroscopy: [/n/4406](/n/4406)
* importing reference spectra: [/n/8995](/n/8995)
###Assembly
Your spectrometer is composed of three functional elements:
* a collimation slit that works as a lens, only allowing parallel light rays through its apeture.
* a diffraction grating that deflects light more the lower the light's wavelength, creating a rainbow diffraction pattern.
* a camera to capture the diffraction pattern, focused on the collimation slit.
[](https://i.publiclab.org/system/images/photos/000/008/890/original/arrangement_illustrated-labeled.jpg)
These elements are mounted on an adjustable velcro bench in a black paper box.
[](https://i.publiclab.org/system/images/photos/000/008/891/original/IMG_20150210_143526_corrected-labeled.png)
####Putting velcro on the bench
Everything is built up from the bench, an ash board 4cm (1.75 inches) wide. We will cover it with the "loop" side of the velcro.
[](https://i.publiclab.org/system/images/photos/000/008/895/original/IMG_20150210_160302-edit.jpg)
[](https://i.publiclab.org/system/images/photos/000/008/894/original/velcro-labeled.png)
The velcro loop tape is slightly wider than half the width of the bench, two strips will hang over each edge a bit.
[](https://i.publiclab.org/system/images/photos/000/008/896/original/IMG_20150210_160318-edit.jpg)
####Assemble the camera block
You will need the camera, double-sided tape, the block, and the hook side of the velcro tape. Try to hold the camera by its edges, as it can be sensitive to electrical shorts.
[](https://i.publiclab.org/system/images/photos/000/008/897/original/IMG_20150210_150024-ed-labels.png)
Start by putting a strip of double-sided tape on the back side of the camera:
[](https://i.publiclab.org/system/images/photos/000/008/898/original/IMG_20150210_150202.jpg)
Remove the pink protective film from the double-sided tape and attach to the center of the block's 45-degree angled side, with the white cable port on top:
[](https://i.publiclab.org/system/images/photos/000/008/899/original/IMG_20150210_150230.jpg)
[](https://i.publiclab.org/system/images/photos/000/008/900/original/IMG_20150210_150258.jpg)
On the underside of the block, attach two short strips of the velcro hook tape.
[](https://i.publiclab.org/system/images/photos/000/008/901/original/IMG_20150210_150318.jpg)
####Make a diffraction grating from a DVD
**Do not touch the surface of the DVD, always hold it by the edges, fingerprints will blur this important optical component.**
We are going to turn a DVD-R into a diffraction grating. An ideal diffraction grating would create a straight rainbow. A DVD produces a curved rainbow, but its rigidity and consistency make it a very good grating.
[](https://i.publiclab.org/system/images/photos/000/008/903/original/ideal-vs-dvd-grating-ed.png)
We have three steps, cutting a quarter of the DVD out, peeling off the reflective aluminum side, and triming to a small piece.
[](https://i.publiclab.org/system/images/photos/000/008/905/original/cutpeeltrim-labeled.png)
_OPTIONAL: Wash the purple ink off of the DVD fragment for greater light transmission. see note [/n/11515](/n/11515)._
#####Peeling apart a quarter of the DVD:
Cutting out a quarter of the DVD with scissors. It may take more than one try to get a good diffraction grating, so save the rest too.
Use a knife or a fingernail to dig under the corner of the DVD quarter and peel the two layers apart.
[](https://i.publiclab.org/system/images/photos/000/008/906/original/IMG_20150210_144414.jpg)
[](https://i.publiclab.org/system/images/photos/000/008/907/original/IMG_20150210_144530-trim.jpg)
You will get two layers. We are trying to get a transparent purple piece without aluminum stuck to it. Some may get stuck to the sides, but we only need a 2cm (.75") square cut from the outer edge.
[](https://i.publiclab.org/system/images/photos/000/008/910/original/IMG_20150210_144232-labeled.png)
Trim down to a small square with roughly 2cm of the DVD's outer edge.
[](https://i.publiclab.org/system/images/photos/000/008/913/original/2cm-label.png)
####Assemble the diffraction grating angle
You will need:
[](https://i.publiclab.org/system/images/photos/000/008/922/original/IMG_20150210_145901-labeled.png)
Overview:
[](https://i.publiclab.org/system/images/photos/000/008/916/original/IMG_20150210_145742-ed-labeled2.png)
[](https://i.publiclab.org/system/images/photos/000/008/917/original/IMG_20150210_145304ed.jpg) [](https://i.publiclab.org/system/images/photos/000/008/918/original/IMG_20150210_145343ed.jpg)
Make sure the bottom flaps are lined up.
[](https://i.publiclab.org/system/images/photos/000/008/919/original/IMG_20150210_145436ed.jpg)
put hook tape on the bottom.
[](https://i.publiclab.org/system/images/photos/000/008/920/original/IMG_20150210_145536ed.jpg)
Put the outer edge of the dvd at the mid-point of the hole, and then remove the handles from the binder clip.
[](https://i.publiclab.org/system/images/photos/000/008/921/original/IMG_20150210_145648ed.jpg)
####Assemble the slit card
You will need:
[](https://i.publiclab.org/system/images/photos/000/008/923/original/IMG_20150210_150959ed-labeled.png)
The collimation slit should be in the DVD sleeve.
_We will attach the slit using the tape as single sided tape-- tape it on top and DO NOT remove the backing film.
_
Line up the collimation slit with the line on the slit card.
####Assemble the box
step-by step video:
For the purposes of this instructional I've highlighted the edges of the box.
Place the box with the printing facing down. Pre-crease all the creases.
crease the box top as well.
[](https://i.publiclab.org/system/images/photos/000/008/650/original/together1-1.jpeg)
[](https://i.publiclab.org/system/images/photos/000/008/656/original/together1-3.jpeg)
Fold the left side of the box to the right, and insert the hold tab in place.
[](https://i.publiclab.org/system/images/photos/000/008/653/original/together1-2.jpeg)
Fold the right side to the left and lay the box top on top so its tabs line up with the slots in the box bottom. Make sure the small rectangular holes on the top and bottom line up. We will put the webcam cable through that hole later.
[](https://i.publiclab.org/system/images/photos/000/008/659/original/together1-4.jpeg)
Insert the tabs together. The box top will not lay flat-- don't worry.
[](https://i.publiclab.org/system/images/photos/000/008/660/original/together1-6.jpeg)
[](https://i.publiclab.org/system/images/photos/000/008/664/original/together1-7.jpeg)
[](https://i.publiclab.org/system/images/photos/000/008/661/original/together1-8.jpeg)
Pull the box top back to the right and fold the inner walls to the middle.
[](https://i.publiclab.org/system/images/photos/000/008/667/original/together1-10.jpeg)
[](https://i.publiclab.org/system/images/photos/000/008/668/original/together1-11.jpeg)
Hook the inner walls together.
[](https://i.publiclab.org/system/images/photos/000/008/669/original/together1-12.jpeg)
Fold the outer walls up and over the inner walls. Use the two circular holes in the outer walls to position the inner walls while folding the outer wall over.
[](https://i.publiclab.org/system/images/photos/000/008/670/original/together1-13.jpeg)
[](https://i.publiclab.org/system/images/photos/000/008/671/original/together1-14.jpeg)
Flip the box upside down and make sure the tabs have all popped out of the bottom of the box. Walk your fingers along the inside of the box and make sure all the tabs are popped out of the bottom.
[](https://i.publiclab.org/system/images/photos/000/008/672/original/together1-15.jpeg)
####Putting it all on the bench
[](https://i.publiclab.org/system/images/photos/000/008/924/original/IMG_20150210_143526_corrected-labeled.png)
Line up the the bench with the side of the box, and align the camera's lens with the 200mm marker on the side of the box. Press the camera block down firmly.
IMG_20150210_144844ed.psd
Place the diffraction grating angle directly in front of the camera block and press it down firmly.
[](https://i.publiclab.org/system/images/photos/000/008/926/original/IMG_20150210_143810.jpg)
Slide the slit card in the front of the box. The printing is slightly off, unfortunately. level the slit card's line just above the box's line. the card should wedge in place on its bottom edge.
[](https://i.publiclab.org/system/images/photos/000/008/927/original/IMG_20150210_160107.jpg)
[](https://i.publiclab.org/system/images/photos/000/008/928/original/IMG_20150210_160149ed.jpg)
Push the camera cable through the cable hole in the back of the box:
[](https://i.publiclab.org/system/images/photos/000/008/930/original/IMG_20150115_200145ed.jpg)
Plug it into the camera-- it only fits one way, don't force it.
[](https://i.publiclab.org/system/images/photos/000/008/931/original/IMG_20150210_161354ed.jpg)
Slide the bench in at an angle, placing it down by the cable hole, and then pushing it down to the bottom.
[](https://i.publiclab.org/system/images/photos/000/008/932/original/IMG_20150210_160613ed.jpg)
You're done! Your computer should recognize your spectrometer as a webcam.
setup live capture for your spectrometer on [Spectralworkbench.org](https://spectralworkbench.org)
###Design Notes
consult the following notes on development for the evolution of this design.
@mathew [paper spectrometer 1](/notes/mathew/11-07-2014/a-paper-spectrometer-design), [paper spectrometer 2](/notes/mathew/12-06-2014/a-paper-spectrometer-design-pt-2)