Version 4.0 of the Public Lab smartphone spectrometer. This spectrometer is a scientific tool that straps onto an Android or iOS phone, tablet, or any camera capable of focusing very close (macro-mode) and allows you to collect spectra. Why would you want one? You can use it to identify the elemental composition of things (light bulbs, olive oil, beer, etc) based on the colors of light they emit. You can even use it to monitor your home brewing progress (http://bit.ly/Xyor6B).

You can order one on Shapeways (https://www.shapeways.com/model/976427/public-lab-smartphone-spectrometer.html), and there is also a papercraft version available here: http://store.publiclab.org/products/foldable-mini-spectrometer

This design, by Brad Dudenhoffer (http://publiclab.org/notes/braddudenhoffer/2-23-2013/mobile-spectrometer-design-update) improves on his previous design with thicker walls, more ergonomic grip and screw-together parts.

Brad -- if you'd like to host this please go ahead and I can take this version down or whatever. Thanks for your great work!

License: CERN OHL v1.1 Public Lab contributors
http://publiclab.org/tool/spectrometer

Here is an updated version of the instructions Brad provided for his previous version:

1. Print the two parts (the base and the body either plain or with the logo)
2. Attach a film grating to the upper side of the base
3. Secure the base to the body with screws
4. Mount it to your phone with removable glue dots or to a phone case with dark double-sided foam tape
5. Use spectralworkbench.org to calibrate, save, and share your spectra.

If you use an extrusion printer such as a Mendel you will probably need to print with support if you want the text to show up. If anybody wants a version without the text, let me know and I will post it ASAP. Also, make sure you have your printer tuned up to print bridges and overhangs very well, because this thing is basically one huge overhang.

This is the grating I have used for the prototype. It is the linear style with 1000lines per mm: tinyurl.com/9tjrz8r . You can also use the film off of a CD, DVD, or BluRay as seen here: http://publiclab.org/tool/spectrometer