[sudo-discuss] Spectral Response Curves

[Marc Juul]

You might want to repeat the question on the Counter Culture Labs mailing
list:

  https://counterculturelabs.org/


On Mon, Nov 11, 2013 at 2:47 PM, Peter Kwangjun Suk <
peter.kwangjun.suk at gmail.com> wrote:

> (Also posted to Noisebridge. Skip if you are experiencing deja-vu.)
>
> Hello,
>
> Right now, I'm doing research for a specialized app to let consumers
> validate products that can be used to treat insomnia. Specifically, I'm
> working on a smartphone app that can act like a light detector for light in
> a narrow band around 470 nanometers. This is the frequency that has been
> shown to suppress melatonin secretion by the pineal gland.
>
> There are specialty products for avoiding late night 470 nanometer light
> exposure (light bulbs, screen overlays, glasses) but these are often very
> overpriced, and there is no convenient way to validate them. There are also
> "ordinary" products that serve the same purpose, but there is no good way
> for people to accurately test them. Currently, people can use a CD or DVD
> as an ad-hoc diffraction grating and look at the resulting spectrum, but
> even this isn't quite good enough. I've bought a narrow bandpass filter for
> 470nm light, and even products that have a spectrum that "looks good" (very
> little blue) can have hot-spots that leak large amounts of 470nm light, and
> it doesn't take much to suppress melatonin. (As low as 0.5 lux for
> prolonged exposures.)
>
> Looking generally at spectral response curves for digital cameras, it
> should be possible to "synthesize" a narrow band detector by taking the
> blue channel response and subtracting the red channel value.
>
>
> http://www.maxmax.com/images/Cameras/Technical/NikonD200_SpectralResponse.jpg
>
> This should effectively produce a "synthetic" instrument that has a
> spectral response curve that would be the camera's blue response, minus its
> red response. Even more helpful, the user should be able to view a
> synthesized narrowband image of the product, to be able to spot leaks and
> hot spots.
>
> What I need: I would like help in scientifically measuring the spectral
> response curve of the "synthetic instrument." I already have a (tiny) 470nm
> filter from Thorlabs, and I'm already aware of Public Lab's DIY
> spectroscope. I would like to use more accurate equipment, however. It is
> important that I can provide accurate information about the performance of
> the app and use rigorous procedures for measurement so that users know they
> can rely on the instrument.
>
> Does anyone have the expertise and access to equipment to help me out?
>
> --SCZ
>
>
>
> --
> There's neither heaven nor hell,
> save what we grant ourselves.
> There's neither fairness nor justice,
> save what we grant each other.
>
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