Ocean Optics USB Spectrometer Indirect Sampler

A printed housing for emissive color measurements that fits an Ocean Optics USB2000/USB2000+/USB4000 sized spectrometer and uses an Opteka white balance card (credit card sized) to reflect light into the spectrometer from the aperture with variable openings.

Print in black, opaque filament with extra perimeters to block out as much stray light as possible. Use a flexible like TPU for the retaining bands, and be sure to use clear filament for the diffusers. A set of parts includes at least one aperture piece, a sampler body, a sampler cover, two large retaining bands (in flexible), and one small retaining band (in flexible).

Tips for use:
The incoming light is limited by apertures in the order above, 100% being maximum open, domed diffused being minimum, but the angle of the incoming light matters less as you go down the list too – you can get fairly large differences with different angles with any of the open apertures, but smaller ones are less able to shine directly on the spectrometer input and diffused ones are the best performers here. If you need attenuation or angle rejection, you have choices of which to use and one extra can fit in the housing.

If your spectrometer's slit is too wide or the light source is too intense, you can use an 18% grey balance card instead of a white balance card instead for further attenuation.

Aperture percentage is given by area of the opening (opening is a 39mm diameter circle), so they can be used ratiometrically, i.e. the 100% opening has exactly double the aperture of the 50% opening hole, and exactly 10 times the aperture of the 10% in square millimeters.