DIY biophysical setups?

[s.]

In extension of the DIY spectrophotometer posted here earlier, I
thought about doing a setup for dynamic light scattering. This
technique can reveal information about what size molecules in a
solution are, and may serve as a complement to electrophoresis. It
seems like it would be possible to do with laser, lenses, cuvettes and
a CCD. Anyone has thoughts on this?

[Bryan Bishop]

How about the cereal box spectrophotometers?

http://groups.google.com/group/diybio/tree/browse_frm/thread/4bb35278daf9fd17/dc1de9bf083b2f82?rnum=1&q=CD+cereal&_done=%2Fgroup%2Fdiybio%2Fbrowse_frm%2Fthread%2F4bb35278daf9fd17%2F355500d6c625f66e%3Flnk%3Dgst%26q%3DCD%2Bcereal%26#doc_44dcc971dea0b764

"A simple spectrometer can be built from a CD and a box. Cut a slit on
one side of the box. Place the CD on the other side with about 60
degree angle. Look down into the openning on the box. The slit should
not be too wide, otherwise the spectrum lines will be blurred. It
should not be too narrow either, otherwise the spectrum is too dim. I
use a 0.2mm wide slit."

http://www.cs.cmu.edu/~zhuxj/astro/html/spectrometer.html
http://www.kosi.com/raman/resources/tutorial/
http://www.thespectroscopynet.com/Index.html?/History_1.html
http://www.scienceofspectroscopy.info/edit/index.php?title=Wiki

- Bryan
http://heybryan.org/
1 512 203 0507

[JonathanCline]

I'm not sure what you mean, though in searching to build a better/
cheaper spectrophotometer, I have seen online some "portable" units
that use USB and the technical specifications state they use a CCD. I
think what they do is to insert different gratings/etc into the unit,
it illuminates against a CCD, and maybe uses the CCD in amplification
mode to boost photon sensitivity. These units are still >$1000
though (whether or not that price is justified is an interesting topic
too). It sounds like you want to process the image data rather than
just count the photons..?


## Jonathan Cline
## jcl...@ieee.org
## Mobile: +1-805-617-0223
########################

[s.]

Im not trying to improve the spectrophotometers out there - Rather im
trying to obtain a solution scatting profile which yeilds information
about the overall shape of the molecules of the solution see:
http://en.wikipedia.org/wiki/Dynamic_light_scattering. One needs to
have a scattering profile of a solution that's why i thought going for
a simple CCD, maybe from an old digital camera would be possible given
some suitable optics are available. Hooking up the CCD stream to an
desktop computer (maybe using http://www.arduino.cc/) for data
analysis (correlation etc) instead of having hardware doing that as in
commercial instruments.

[Thomas Knight]

Very high resolution linear CCD imagers are found in all cheap
scanners, along with the electronics to drive them. For $50 new or
free used, you can get a 4000 pixel linear imager. A plastic replica
grating from Edmund and a slit makes a pretty good spectrometer.

[Jeswin John]

Scanner? You mean flat bed scanner? If so, I see them all the time on Craigslist for free