Alternative chemical sensors, such as webcam spectroscope

rsevs3

Couple of links for you.

http://publiclaboratory.org/notes/warren/7-17-2012/failed-3d-print-mobile-spectrometer-attachment

I know there is more but i cant seem to find it...

SuperVeg

creuzerm what 3d printer do you have ?
I have been looking into them, it seems the cheapest hobbiest one that produces OK results would be the maker bot, but I have no idea.

This is a very interesting thead/topic I just have too many other priorities to allocate any time at all to it. Maybe one day :think:

creuzerm

Ronmaggi wrote:

Those are the most useful first two posts I have ever seen! How do you measure ph with cabbage juice?

http://chemistry.about.com/od/acidsbase ... icator.htm

It appears that it doesn't have a very good shelf life unless you add something like BHT. I wonder what that would do to a system.

creuzerm

There isn't much prior art for the cell phone based spectroscopy. The post that you linked to, and a high school lab that uses student provided cell phones to image the color bands.

My printer is the Makergear.com Prusa kit.

As to the CD/DVD not working, I saw one setup where that was all they used. People keep using these at 45 degree angles or so. That geometry may be important. Something to play with I guess and see how things work out.

SuperVeg

I can help with some proper 3D CAD drawings if needed. Probably much better than using sketchup etc..

creuzerm

SuperVeg wrote:

I can help with some proper 3D CAD drawings if needed. Probably much better than using sketchup etc..

I intend on using a program called OpenScad as it will allow me to make a parametric setup. I can just key in a few measurements and the right sized and shape object is drawn. In theory.

Feel free to draft up what would work for your phone. I can print it for you for just a little bit over my cost (I tend to round up to the nearest dollar or two).

BullwinkleII

If the mobile thing pans out, perhaps you could design an adjustable one, with a couple of nuts and bolts to make a one size fits all adapter.

rsevs3

the 45 degrees is important. That is the angle that the CD refracts the light. The light shines through the CD, not reflected off it.

creuzerm

BullwinkleII wrote:

If the mobile thing pans out, perhaps you could design an adjustable one, with a couple of nuts and bolts to make a one size fits all adapter.

Maybe for something like a one size fits all iPhones. There are just too many camera geometries to make a one size fits all device. The genius of 3d printers is that I can just print exactly what I need.

I'd need to make units for dozens of different phones before I could find common patterns between phones.

creuzerm

rsevs3 wrote:

the 45 degrees is important. That is the angle that the CD refracts the light. The light shines through the CD, not reflected off it.

In my research I stumbled across http://sci-toys.com/scitoys/scitoys/lig ... scope.html which does the reflect off of a cd thing.

Ideally i'd want a collimator and real refraction gradient. But, I don't have those at the moment, so I am making my first one out of garbage.

One man's trash is another man's spectroscope?

creuzerm

I just tested the CDROM diffraction gradient using the camera flash. I used a bit of electrical tape to mask of just a slit of light.

I get a diffraction! I am hoping it's 'clean' enough to suite our purposes.

I am happy enough with the test that I am going to go forward and make this thing!

BullwinkleII

Sometimes when we watch movies like "The Terminator", we see people knocking up a ray gun from an old clock radio and an empty Milo tin and we suspend disbelief for the sake of the ride, but the reality is, you people are working on a spectrometry device cobbled together out of dental floss and hope!

Amazing!

It was only a few years ago that this subject was the stuff of Nobel prizes. A few years before that it was the stuff of science fiction, and a very few years before that, it wasn't even stuff!

You people rock!

Ronmaggi

I always love when I hear a scientist that came up with something really cool say "I got the idea from a comic book." So many times what starts as fiction becomes fact over time.

BullwinkleII

And that's why I'm putting all my money into iBeer Pajamas.

rsevs3

Just received shipment notification of my Raspberry Pi.

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