
Constructing a spectrometer using a CD - gwern
https://www.cs.cmu.edu/~zhuxj/astro/html/spectrometer.html
======
cing
A great open-source spectrometer built the same way is available from
PublicLab here: [http://store.publiclab.org/products/desktop-spectrometry-
kit...](http://store.publiclab.org/products/desktop-spectrometry-kit-3-0) (or
you can just build it yourself using their designs on the Wiki). PublicLab
also has a repository for spectra so you can calibrate and compare with
others.

------
p1mrx
You can also buy diffraction glasses for under $10. They're marketed as "rave"
accessories, but I found them useful for quickly identifying incandescent
light bulbs hidden inside fixtures, in order to replace them with CFLs.

~~~
IIAOPSW
Or just get diffraction gratings. No need for the silly "glasses" markup, you
know the number of lines per millimeter, and you can get 25 of them for around
the same $10

[http://www.amazon.com/gp/offer-
listing/B00K6K3MCW/ref=sr_1_1...](http://www.amazon.com/gp/offer-
listing/B00K6K3MCW/ref=sr_1_1_olp?ie=UTF8&qid=1443337421&sr=8-1&keywords=diffraction+grating&condition=new)

------
WalterBright
Cool project. Makes me wonder about the spectrum of an LED light bulb.

~~~
p1mrx
White LEDs are just blue LEDs with a yellow phosphor, so the spectrum usually
has a blue hump, and a red-green hump:

[http://www.soundandvision.com/content/led-vs-cfl-bulbs-
color...](http://www.soundandvision.com/content/led-vs-cfl-bulbs-color-temp-
light-spectrum-and-more)

------
facepalm
This looks great! I'll try this with my kids soon - I try to do at least one
experiment every week...

------
ersii
This did for some reason wake a bit of nostalgia in me from the earlier days
of the public Internet. I bet it's the spartan design and the lack of anything
else other than the to-the-point content. (That said, fascinating content -
might try it out!)

~~~
gluelogic
Just made one this morning after reading the article. Super easy and works
like a charm! What fun

------
antoinealb
If you combine this with a bit of numerical post processing and some
calibration with a laser pointer you can get a pretty precise result. We did
this in university, it was fun :)

