Public Lab Research note


Oil testing spectrometry workshop at Fab 10

by warren | July 05, 2014 09:42 | 258 views | 5 comments | #10661 | 258 views | 5 comments | #10661 05 Jul 09:42

Read more: publiclab.org/n/10661


I ran a small session on developing the oil test kit spectrometer yesterday in Barcelona (http://fab10.org). Basically, we've been trying to design a sample chamber so people can do quick and standardized fluorescence scans of different samples in small bottles. This seems like a good opportunity to revisit the design of our spectrometers in general and maybe even come up with a cheap foldable version of the whole thing. Mathew Lippincott and I have been working on this a bit (see links at upper left) and this workshop seemed to be a good opportunity to keep experimenting.

We built the sample holding chamber around the basic foldable spectrometer people have been building for years. It allows for a laser pen to be inserted but I think it'll make more sense with UV LEDs down the road.

IMG_20140704_180024.jpg

It needs to be a bit taller since phones are so big -- kind of annoying. We used it sideways but the phone interface isn't ideal since the menu bar takes up so much space that way.

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Aisha, who took part in the workshop, developed a smaller handheld version which looks a bit like dusjagr's (linked to from the top left). It worked as a removable addition to the basic foldable spec, which sleeved into it:

IMG_20140704_185718.jpg

It worked well; here's a clear fluorescence spectrum:

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Next steps

We have to figure out how to close the bottom easily... I think it may be worth it to go to a larger piece of paper... Maybe 5+ in wider. That'd give us flaps and a taller box, but could be harder to ship. Could we have it fold in half and make the seam part of the design? I know Mathew's working on this in recent days so I'm eager to see what he's come up with.

Also: why does this design look familiar??

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5 Comments

I was thinking about this very issue today. It just doesn't make sense to hold the phone at an angle though - how can we rearrange this idea so that the phone is flat and on top of a box looking down? Wouldn't this be a better choice of design? Hmmm...

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Well I like the angle in part because it seems convenient for viewing on a table or countertop... Almost like a lectern. And we can adhere a phone case to the front so its a snug fit. Also, we (Mathew and i) wanted this design to be workable for a phone or a webcam. But if we wanted to reposition, a mirror could maybe be inserted? Actually if we had good enough mirrors we could make the whole thing more compact by reflecting back and forth in a chamber. But then it'd be significantly harder to build and the required materials would be more of a barrier.

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Another thought. To avoid needing batteries for the LEDs, I wonder if we could power them off the headphone jack of a phone... Like this laser accessory. I don't know if that requires doing something on the phone but we could Google this sort of accessory to find out.

IMG_20140701_210202.jpg

Too bad the laser pointer is only for professionals. :-P

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btw... we have continued a lot... see what urs made: http://hackteria.org/wiki/DIY_NanoDrop

m

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Cool yes I forgot about that dusjagr!

Sketch of audio powered LED:

IMG_20140707_181148.jpg

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