Public Lab first began developing cheap spectrometers in the winter of 2010, after the Deepwater Horizon oil disaster in the Gulf of Mexico. Since then we've made enormous progress and have a variety of designs for less than $100, including:

• a USB webcam based kit (plans)
• a molded plastic smartphone-based kit (plans)
• a very affordable foldable papercraft kit which attaches to a smartphone or webcam (plans)

Of course, the plans for all of these are on the Public Lab website and are open source hardware designs, so you can always make your own -- the kits are intended to help you get started.

You'll also need a frame to hold your sample container and align a laser beam perpendicular to your spectrometer. For that, we've developed the Beta Oil Testing Kit, an add-on to the Desktop Spectrometer v3.0 pictured here, attached:

If you join the Beta testing program, you can then sign up for the add-on "Beta" Oil Testing Kit (see parts list to assemble your own) in combination with the existing Desktop Spectrometry Kit, which is what was used in the examples on this page. See this excellent research note for assembly instructions.

Parts list

In progress: these are links to where you can buy parts to assemble your own oil testing kit

• Possible upgrade: nail polish bottles, with built-in bottlecap-swabs. An all-in-one, one-use pre-filled with mineral oil! Maybe you break off the swab and throw it away, or maybe it doesn't matter.

  • http://www.alibaba.com/product-detail/nail-polish-bottles_862081740.html?s=p
  • http://www.alibaba.com/product-detail/10ml-empty-square-nail-polish-bottle_1042482910.html?s=p
  • http://www.alibaba.com/product-detail/0-4oz-Art-Nail-Polish-Bottle_674230480.html

• http://www.ebottles.com/showbottles-bottle-1556-kw-ELIQUID_VIALS.htm

• http://www.ebottles.com/showbottles-bottle-1329-gclid-Cj0KEQjwopOeBRC1ndXgnuvx8JYBEiQAq4RPt_MBIoRstpRXJzK66iXV1lbaZ6J7TWOot8oR6wDas7QaAops8P8HAQ-kw-NAIL_POLISH_BOTTLES_WITH_BRUSHES___GLASS.htm
• http://www.freundcontainer.com/french-square-glass-bottles/p/v4225B01/
• 5oz mineral oil (baby oil -- the added fragrance doesn't fluoresce): $3 - http://www.amazon.com/Johnson-Baby-Oil-Kids-Ounce/dp/B000GCJM06/
• an eyedropper: $0.05 0 http://www.sciplus.com/p/CAP-WDROPPER_39038
• a 405nm blue/violet laser pen: $3 from Alibaba, or for purchasing singles here Some people feel having the caps are useful for dispersing the laser when necessary so if you want more caps perhaps this will be to your liking
• 4 flat-sided jars: $0.35 each - http://www.sciplus.com/p/WHITCAP-BOTTLE_48212
• cotton swabs: $0.10
• olive oil test sample: $0.17
• paper instructions (yet to be made)