Public Lab Research note


Sampling extension for smartphone specs

by warren | February 07, 2014 23:28 | 89 views | 8 comments | #10020 | 89 views | 8 comments | #10020 07 Feb 23:28

Read more: publiclab.org/n/10020


Mathew Lippincott and I have been talking about the Oil Sampling Kit and how to streamline it eventually for mobile use. The Smartphone Spec is designed to accept "expansion packs" and this seemed a good opportunity to develop one which we could prototype 3d-print. It could:

  • include built-in lighting
  • accept 2 sample containers; a sample and a control
  • have completely fixed geometry between the lighting and the samples
  • use UV LEDs instead of a blue laser, and
  • include a battery and different lights inside the enclosure

Interesting! So I made a quick Sketchup model (attached) pictured above. It's not to scale or ready to print or anything, but I'm just trying to figure out a good orientation and internal layout.

sampling-kit.skp

Above, see how the 2 cuvettes are separated by a wall. The "foot" at the back left inserts into the end of the smartphone spec. I've left a cutaway so you can see the inside.

Can you improve this design? Make it printable?


8 Comments

Jeff, If you include the dimensions of the part of the spectrometer that inserts into the window, and the dimensions of the cuvettes, the next mockup could be closer to a usable reality. If LEDs will be the only thing requiring power, are coin cells sufficient, or will you need that AA battery? Will you have to block one cuvette window to take a reading from the other? Is a little sliding door required for that?

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cool

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I wanted to work off of the actual models (or prototype models) Mathew and others made, but didn't have time to do a scaled model. Also, figuring out the geometry and scaling it are separate problems (at least how my brain works) but you're right and Sketchup can help us simply scale this design. It'll also take some "wall sealing" to give the model volume.

Some useful links:

Spectrometer 3D design files (injection molding and 3d printing): http://publiclab.org/wiki/smartphone-spectrometer#Design+files

Some thoughts on an SLR adaptor, which could be useful to attach sample containers to also: http://publiclab.org/notes/warren/07-20-2013/proposal-slr-spectrometer-attachment

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I have a smartphone spectrometer, so maybe bring a cuvette to SNOWFEST and that should be all I need.

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I've been trying to find stand-alone diodes, and it seems that there are several chinese manufacturers of 405nm laser diodes on Alibaba that are quite affordable ($0.50-2) range. so some sort of solid state calibration + emission spectroscopy setup seems possible with a very basic diode circuit board.

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Huh. do laser diodes have as narrow a bandwidth as a laser?

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The laser is a diode + a lens. Unfocused it still goes in a pretty straight line for short distances at least. There are all-in-one surface mount DVD lens + diode assemblies too. they just cost more. Its worth a shot without a lens for the cost break.

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wait, shorter answer-- The bandwidth is the same, but the beam will be wider.

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