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Cost Analysis & Parts List Breakdown Charts
12/17/2016 at 09:54 • 0 comments -
IR Scan [Infra-Red] Phase II Testing Platform 3 (cmos material range test)
12/14/2016 at 21:11 • 0 commentsTest platform III for the DAV5 V3 Raman spectrometer prototype 1 [a]
The plot below illustrates the IR beam divergence at 8 degrees and at 100mW/70mW pwr up.
The importance of these series of tests are, I am determining the material range of the semi-conducting metal oxide, in order to validate the spectrometer's ability to "see" in the infra-red range. This initial test is very promising because I didn't have to adjust the ROI very much to get a good reading.
So far the sensitivity of this particular cmos detector is very good and it helps that it was spec'd out for night vision use, both peaks are close to the specs of this IR illuminator at 805nm, although I cannot find enough detailed specs on it to determine any plus or minus variance. This project demands this kind of precision, there is NO work around!
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Replaced DVD Diffraction Grating for The DAV5 V3 (a) Raman Spectrometer
12/13/2016 at 15:32 • 0 commentsReplaced the 4.7G DVD piece I was using for the diffraction grating, and replaced it with an 8.5G one. Now I have a ruling density of 0.36mm, which now gives me a wavelength range of 360nm (0.36mm *1000 = 360nm) and 2770 lines per mm, for a spectral resolution of 0.18nm, using my 150mW laser's FWHM as my measurement:
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Spectral Bandwidth Testing For The DAV5 V3 (a) Raman Spectrometer (prototype 1a)
12/12/2016 at 12:05 • 0 commentsBelow is the formula for solving spectral resolution (bandwidth,) I am using a 0.12mm acetate film slit, if I used the theoretical side of this equation I could input the slit with and I would get a theoretical FWHM of 2.87nm (1 x 0.12mm x 1540 = 184.2 wavelength = 532nm/184.2 = 2.87,) but the more practical application is to use the actual laser line itself.
So here I have a spectral bandwidth of 0.15nm which is 99.5 percent close to industry standard.
Front view of my prototype 1 (a) with M2 mounting holes cut in front of the cuvette holder for a fiber optic coupler.
Below are some design mods that I need to make, they didn't interfere with operation in anyway but were a result of the 3D printing process that I'll have to keep in mind the next time. (1) the silver mirror is 3.2mm thick, the final product came out about 1.5mm too large, so I will have to compensate the next time. (2) I have to raise the camera mounting block by 10.38mm, (3) expand the 38mm focal lens holder base by 5mm square.
Next pic, (1) 25mm filter slot on camera mount came out perfect, (2) had to redesign the DVD diffraction piece and lay it flat on top of the filter and secure it in place with a locking sleeve. (3) 32mm focusing lens assembly came out fine, except for the 25mm rear filter slot, I will have to expand the diameter a bit more.
So I can't use the Longpass edge filter yet.
A closer look at the detector set up.
All in all, the first initial testing exceeded my expectations. This prototype will be the prelude to the final product, as my goal is to design this set up as a one shot assembly, pre-drilled holes (well, 3D printed ones,) for the enclosure and components, and easy interlocking 3D printed parts, with a tolerance matching that of industry standards.
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3D - Parts Are In! Partial Assembly of The DAV5 V3 Raman Spectrometer (prototype A)
12/10/2016 at 20:49 • 0 commentsFrom left to right; DVD diffraction grating W/18 x 18mm frame, 38mm dia. Focal lens mount, 36.5 x 52mm main focusing lens assembly W/ 32mm dia. lens, cuvette holder (sample holder,) W/ 0.12mm exit slit, 3.2mm Square mirror mount, JDEPC-05 cmos camera mount assembly W/Schott Glass longpass (280nm,) color filter.
Forward view
Vertical view
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Adjustable Mechanical Slit W/Metric Micrometer 3D Printable
12/05/2016 at 11:20 • 0 commentsThis idea came about from the tray mechanism of a CD-ROM drive, I liked the screw idea it has for the lateral movement controlled by the little stepper motor, so I took a "sneek peek," inside a product from Thorlabs using the reverse engineering feature from FreeCad.
I have been thinking about this concept for months now but couldn't figure out how to make it work effectively, and cost effectively, so I merged both idea's from thorlabs and the CD-ROM drive and came up with this design and theoretically it should work. I built a very crude model and it does work (with some minor problems,) but it does work, so I went ahead and designed this model with as much precision as possible.
Even for 3-D printing this might be pushing the envelope, but if this works, it will be a beautiful thing! So before uploading any STL files for this, I am going to get the parts printed and assemble and test it, to validate it's operation and hopefully its success.
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Practical Theory Of Operation For The DAV5 V3 Spectrometer
12/01/2016 at 17:07 • 0 commentsPractical theory of operation the DAV5 V3 Spectrometer
Raman spectroscopy provides valuable structural information about materials. When laser light is incident upon a sample, a small percentage of the scattered light may be shifted in frequency. The frequency shift of the Raman scattered light is directly related to the structural properties of the material. A Raman spectrum provides a "fingerprint" that is unique to the material. Raman spectroscopy is employed in many applications including mineralogy, pharmacology, corrosion studies, analysis of semiconductors and catalysts, in situ measurements on biological systems, and even single molecule detection. Applications will continue to increase rapidly along with further improvements in the technology. A Raman signature provides positive material identification of unknown specimens to a degree that is unmatched by other spectroscopy's. Raman spectroscopy presents demanding requirements for the detection and resolution of narrow-bands of light with very low intensity and minimal frequency shift relative to the source.
Fig.1 Basic set up, cuvette holder with ½” entrance slit. Front face on enclosure has a ¼” (same size as the cmos sensor) exit slit, which then illuminates a 532nm longpass edge filter (built in to the rear face of the focusing lens assembly) this blocks the laser’s broad band wavelength and allows only the Raman signals (much weaker,) to filter through to the next stage, which is the 10x focusing lens at the front face.
532nm Longpass edge filters ($105.00 EdmundOptics.com)
Transmission curve for the 25mm longpass filter employed in the DAV5 V3 spectrometer. This filter blocks the laser signal and allows the Raman signal through, in turn which is amplified by the 10x objective eye lens before striking the focusing mirror.
Fig.2 Cmos detector set up, consisting of the JDEPCov-05 cmos sensor, 25mm Schott glass stray light filter and 4.7G DVD piece (I dialed the DVD piece down from 8.5G to 4.7G, 1540 lines per mm is just fine.) used as the diffraction grating.
Fig.2a This was the design I had for the detector mount set up, which I changed to accommodate the Schott filter, which made more sense because the filter needed to be behind the DVD piece and NOT in front. So, figure.2 is the updated version.
Fig.3 Silver coated protected mirror, 2” square, 3.2mm thick. This is the ONLY mirror used in this set up, the reason is my own research over a year and the precise alignment and filters and focusing lenses used, plus I am using a superior data processing software and live capture program (Spectragryph 1.0 and Spekwin32.)
Fig.3a This data plot represents the specifications for the mirror used in this spectrometer, it has a reflectance of 96 – 97 percent @ 45 degrees of angle of incidence (AOI.)
Advantages of this design and set up;
- Detector is easily upgraded by removing the mount and replacing with a new one designed for the new detector.
- No new alignments must be made.
- DVD diffraction grating and Schott filter screw back in place to the new detector mount.
- Raman performance at a much lower cost (average cost for OEM mini Raman spectrometers are at least $6000.00 US dollars.)
- The DAV5 V3 spectrometer can cost as low as $600.00 US, with 95 percent of parts 3D printed.
- Focusing lens assembly provides an all in one performance design by utilizing an inclusive rear filter inlay and front end lens cavity with locking sleeve assembly for easy removal and interchangeability.
- Enclosure lid design has outer lip overhang and 2mm inlay for tighter fit and water resistive properties.
- NO complicated tuning or filter set ups because of its precise alignment and filter design.
This is the beginning of phase II, assembly and practical testing.
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Drawing 1a DVD Diffraction Grating Frame assembly
11/30/2016 at 19:42 • 0 commentsThis is the frame assembly from the previous drawings that illustrate the diffraction grating placement on top of the Schott glass filter at the detector. The DVD piece is cut @ 20 x 20mm and placed within the 1mm inlay of the frame with a dab of glue (DO NOT use crazy glue!)
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CMOS Camera Mount With Schott Glass Filter (25mm dia.)
11/29/2016 at 15:45 • 0 commentsNew JDEPC-05 camera mount for the DAV5 V3 spectrometer, redesigned to accomodate a 25mm Schott glass filter for blocking stray light at the detector;
Transmission (including surface reflections) is plotted as a function of wavelength to the right. The region shaded in blue represents the range over which this filter is transmissive. At wavelengths shorter than the cut-on wavelength, the filter blocks the light.
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32mm Plossl Type Focal Lens Assembly
11/28/2016 at 08:19 • 0 commentsThis is the 3D printable version I designed of the 32mm Plossl focusing lens, you can use any 32mm lens that has a dia. of 29.78mm X 8mm thickness.