Public Lab Research note

Oil testing spectrometry workshop at Fab 10

by warren | July 05, 2014 09:42 05 Jul 09:42 | #10661 | #10661

I ran a small session on developing the oil test kit spectrometer yesterday in Barcelona ( 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.


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.


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:


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


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??



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.


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

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btw... we have continued a lot... see what urs made:


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Cool yes I forgot about that dusjagr!

Sketch of audio powered LED:


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