Back in August 2012 Jeffrey designed a version of the smartphone spectrometer which he had 3D printed, but unfortunately the results were less than ideal. He made a post on Thingiverse looking for some help with the design.
I am a research chemist and love making tools and instruments for use in the lab. I also hate that most scientific instruments are priced way over the budget of many citizen scientists. I had also recently finished building my MendelMax 3D printer and was itching to put it to use For Science! I was able to modify his design and make a functional spectrometer which is printable on the fused powder printers used by Shapeways as well as the extrusion printers used my most hobbyists. I shared it with the community, made a few improvements, and thought I was done with it.
A little while later I was contacted to see if I would help design an official molded spectrometer. I didn’t have much experience with molded manufacturing but jumped in head first. So far I have been through 19 iterations of the design. We tried fold-down, flip-out, and fold-flat designs before settling on a much more robust rigid backpack design. With a lot of input from the great PublicLab team we finally refined the design to something that looks like it belongs on the back of a smartphone. I recently sent the 3D model to our manufacturer and am waiting for some final feedback so we can get these things out there to the citizen scientists who have been patiently waiting.
Here is what we have come up with.
It is a three piece design and will be molded in black high strength plastic.
The slit-end will work just like the paper model but also utilizes a hood to cut down on stray reflections. The hood is sized to hold a standard 1cm square cuvette so you don’t have to worry about your sample moving and changing the spectrum. A pair of magnets recessed in the hood allows for the attachment of future accessories such as an LED light source, a laser, and who knows what else (microscope/telescope eyepiece?).
The square recess on the side is the mounting location. It is 20x20mm square and has a recessed magnet on the opposite side to hold the spectrometer to the mount. The first mounting plate will be for a standard ¼” photography/video tripod screw. The entrance slit is set at about 1mm which is very functional but a bit wider than ideal. There is plenty of room to overlay your own narrower entrance slit if you want to sharpen the peaks a bit at the loss of a bit of light intensity.
I hope to hear back from the molders this week and have any necessary corrections finish very soon.