🚀 go-pugleaf

On Sun, 12 Aug 2012 23:52:09 -0700, Jeff Liebermann
<jeffl@cruzio.com> wrote:

>On Sat, 11 Aug 2012 23:22:35 -0700, Jon Kirwan
><jonk@infinitefactors.org> wrote:
>
>>My intent is to only use parts that a student can afford to
>>buy and OWN at home. 
>
>Is $30 too much?
><http://shop.breadpig.com/collections/publiclaboratory/products/desktop-spectrometry-kit>
><http://spectralworkbench.org>

Yes, $30 is too much and so is requiring a computer. To start
out, the students build a paper box and use a DVD and just
their eyes.  The DVD is far far less than $1. (20 cents?) The
box is ONE sheet of cardstock (a few pennies.) The glue is
Elmer's and doesn't need much. That's it. The DVD is the only
tricky part. I just prefer the DVD-RW because it doesn't have
a terrible blind spot in the red band (DVD-R absorbs heavily
over a range in there.)

Some students will then move on to the idea of a camera and
using a computer to process the pixels. There is some work
involved in that next step (I've already written all the
wavelength calibration software, though.) Not all students go
there. Most just stop at the box and use their eyes.

>I've been using a piece of DVD-RW grating over the lens of my cell
>phone camera as a spectrometer for looking at LED lighting.  Not
>great, but usable.  Most 12 year olds and up have cell phones, usually
>with cameras.
><http://www.news.illinois.edu/news/10/1007scheeline_spectrophotometry.html>
>Now, getting the picture out of the cell phone camera is another
>story.
>
>However, if you want cheap, diffraction grating glasses at $30 for 50
>glasses:
><http://www.ebay.com/itm/280806593566>

I'll stick with the DVD-RW. 1350 lines/mm.

Jon