| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| stoft | "Without a "reference standard" the measurements will all be relative; not absolute (like ppm [parts per mission]). So, the relative concentration w..." | Read more » | almost 7 years ago | |||
| stoft | "The posted graphs are, mostly, just individual experimental plots. Assuming 1) working spectrometer, 2) has been wavelength-calibrated using a CFL ..." | Read more » | almost 7 years ago | |||
| stoft | "Nice graphics. Yes, white LEDs are not broad spectrum. If it's of any help, I set (Matlab code) the ELP camera to: Manual Exposure, Exposure=-3 (-1..." | Read more » | almost 7 years ago | |||
| stoft | "There's still some clipping (source light intensity too high) so a comparison, using a cardboard mask (with a small hole in it), between the two bu..." | Read more » | about 8 years ago | |||
| stoft | "No I don't think it is just inherent in the camera. The blue led has a fairly narrow spectrum (say 25nm at most) so producing a 150nm 'spread' woul..." | Read more » | about 8 years ago | |||
| stoft | "I note that 1) your spectrum does "fit" though it is 2) "offset" a bit from center which is likely related to the angle. (Just to identify what is ..." | Read more » | about 8 years ago | |||
| stoft | "The angle is a function of (mathematical) of the detectable wavelength range and the diffraction grating (DVD) line spacing. My calculations and my..." | Read more » | about 8 years ago | |||
| stoft | "@stef, thanks for the curve data. While the data is useful for comparison with relative sensitivity curves of other cameras, the data, unfortunatel..." | Read more » | about 8 years ago | |||
| stoft | "What I've read is that the RPi camera used to use the OV5647 camera chip but has "upgraded" (changed chips) to a Sony IMX 219 PQ CMOS image sensor ..." | Read more » | about 8 years ago | |||
| stoft | "Jeff, I inserted the component details in the note above, just before the plots. As to the RPi camera, it seems to have two "difficulties" which n..." | Read more » | about 8 years ago | |||
| stoft | "Jeff, yes, the data is being collected, and yes, higher resolution does improve observation of detail like slit differences. I'm evolving some new ..." | Read more » | about 8 years ago | |||
| stoft | "I'd guess that it's just the collection and comparison of key measurements extracted from the spectra which may result in 'sensitivity' estimates. ..." | Read more » | about 8 years ago | |||
| stoft | "Thanks Jeff; understood. I'm presently working on a higher resolution P-4 spectrometers (including monochrome) so might find a spot for comparison ..." | Read more » | about 8 years ago | |||
| stoft | "@warren, I didn't see you comment about a draft of test types for replication experiments so I just posted them at the end of this published note o..." | Read more » | about 8 years ago | |||
| stoft | "@warren, the black ink looks quite dark in the photo and seems easy to apply. Hope it cures well. I believe the primary factors are 1) the black c..." | Read more » | over 8 years ago | |||
| stoft | "@abdul, ok so we've just differentiated the [1] and [2] kits; the option [1] should ship thin, paper only with no 'solid' materials other than the ..." | Read more » | over 8 years ago | |||
| stoft | "Interesting thought. I'll suggest using blue and red LEDs which then allows monitoring apparent wavelength shifts as well (when slit and camera or ..." | Read more » | over 8 years ago | |||
| stoft | "@abdul, interesting observations .... so here's a starter list. [0] Folding Vers (Cute, zero-cost, spectrum concept), [1] Paper Vers (Functional, l..." | Read more » | over 8 years ago | |||
| stoft | "@warren, nice to see a design from the West suddenly appear in the East! Sneaker-net variant of NC machining; hope the design actually works for yo..." | Read more » | over 8 years ago | |||
| stoft | "@mathew, good thoughts. I'm technical but from experience I see the need to include the market, user, next-bench, test, manufacturability, environm..." | Read more » | over 8 years ago | |||
| stoft | "@stef, Thanks for your observations; glad to see the creative spirit alive and well. Here's a link to a note (which includes two other links) about..." | Read more » | over 8 years ago | |||
| stoft | "I added a comment; I think that at this abstract level, the assumption of conceptual mode is fairly implicit. The entire post is focused on proposi..." | Read more » | over 8 years ago | |||
| stoft | "Yes, both aluminum and silver oxidize very rapidly which is why all mirrors with those surfaces are coated -- the type of coating affects the mirro..." | Read more » | over 8 years ago | |||
| stoft | "@cristoforetti, the camera focal distance is based on using a slit to simulate collimated light -- non-collimated light gives multiple diffraction ..." | Read more » | over 8 years ago |