Public Lab Research note

Testing both spectrometer 3.0 and OTK - assembly Beta program

by Tofu | October 08, 2015 01:49 08 Oct 01:49 | #12281 | #12281

Tofu was awarded the Basic Barnstar by stevie for their work in this research note.


First part, assembly of the spectrometer and OTK

Shipping boxes, simple, elegant


I like the idea of a "low cost home spectrometer" so I might get a little overboard here...

OK, so is the kit safe with kids around? A believe yes (But parents need to hide the laser and oils) The only caution is the possible small and sharp DVD pieces Is it easy to let on the side partly assembled? Yes Is it easy to repair? Yes Can it be managed and used on a kitchen table? Yes

What about a rainy delivery of the kit? Can high humidity be a problem for the OTK?

Comments for the written documents - Page numbers for quick reference - To some people, going to step 1,2,3 is easier and also make troubleshooting easier - In the images, the contrast for the edges should be more clear. I tried to assemble the kit with only the content of the boxes but also had to rely on the website - A list of proposed tools for assembly and testing (scissors will be easy to get but not everyone has a CFL) -Bigger and uniform fonts

Straightforward instructions for the DVD, must be added earlier in the text that the edge of the DVD must be oriented


If you have large fingers, it takes a moment to get used to the tape


The only place I find a little fragile on the spectrometer


Again, straightforward


For people not used to large bands of tapes, it could be added to slowly remove backing from the velcro as you apply it


Adjusting the slite with the tip of scissors worked well


The OTK pieces are a little less obvious to figure out as is (With blurry image...)


I knew the v shape piece was too big but it was a good place to try what if someone tried hard to make it fit anyway Well, I think the v shape could be doubled (the m shape also), I know that I will take out the laser and hide it from kids at home, so I believe it should be stronger


Removing the extra 1-2 mm from the v shape piece


I had some trouble with this fold As noted elsewhere, a white mark should be added to help find the openings


What demanded a readjustment is the tape on the back of the camera. After I started calibrating and experiencing with various light sources, moving the usb cable moved the camera slightly. I will look soon into posted solutions


And in all it's glory...


So general feeling after assembly Very satisfactory to build! The spectrometer is more "intuitive" and demanded me less thinking and back and forth between the website, the written instructions and trying figuring it out

The spectrometer has double walls, I believe the OTK should too, since it is as likely to experience light beatings##

The camera could have a more stable place, I will try to place it between two wood sticks (popsicle) or maybe something else

One question I have is if some oil is accidentally in contact with the OTK, could there be a way to wipe it out, change parts, or use materials that won't be affected? Would soap or a specific not too toxic solvent be used?



Regarding humidity, we've talked about offering an upgrade with a sheet-plastic material, die-cut the same as the paper edition. I hope we figure out how to do this. @tonyc - this post is a good overview of assembly of the OTK and Spec v3, and some good thoughts for revisions as well. Thanks Tofu!

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Very good summary and really good ideas for revisions. The concern about not only humidity but also oil contact makes a plastic housing version something to investigate. I like the idea of adding similar double-wall construction to the cuvette frame, too.

The laser around kids is a real concern, as it is not a laser pointer you'd want to play with, as it is in the UV range that can injure eyes! I still want to review the safety issues around this, and suggest we actually seal the laser in a way that you have to read the warnings before opening it, not just including warnings in the printed matter.

I prefer to not even call it a pointer at all, and I want to make sure that word isn't included in our documentation. It's the "eye injuring stick" when I ask for it.

thanks for the great note on assembly!

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