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3D-Printable Raman Spectrometer

The only thing worth doing, is the thing worth doing right!

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The DAV5 V3 Spectrometer will be the only project build here on Hackaday in its category, with ongoing, full performance and specifications documentation, this project will also be at least 85-90% 3D printed!

This project has 4 major ;

a. To build a rugged and reliable low cost spectrometer with at least 85 to 90% 3D printable parts.

b. A spectrometer capable of producing consistent and professional quality results in the field, home or Lab

c. A device with upgradeable capabilities

d. An open source instrumentation device W/CAD(CNC .stl files)/schematic/technology files with NO copyright and/or licensing agreements.

**This project will also have full professional/analytical and chemical documentation.

***This project is in NO way related to, or in anyway, conceptualized to replicate the 3D Raman-Pi project here at Hackaday.***

*Update* 5/8/2017 2:56AM

*UPDATE* 5/1/2017 11:23AM

I had to make a revision to the firmware for the ATmeg1284P driver software, it's in a zip file at Github, same link below "

TCD1304DG_drvAPR301.zip

I rewrote to firmware on AtmelStudio 7.0 and uploaded the files to a new repository at my Github website, so it's all nice and tidy :) Here is the repository; http://github.com/dhaffnersr/AtmelStudio-7.0


*UPDATE* 4/29/2017 3:55PM

This is the development board that I use from MCUdude over at the Tindie.com store, not only is this thing versatile, but lets me switch between different 40 pin chips, which of course right now I am using the ATMega1284P. One in the CCD detector circuit board and here in this Dev board.

This is my board with the ATMega1284P chip;

This is my projects MISSION STATEMENT:

This is the primary motivation for doing this project from its inception over a year ago to present day, I specialize in biological pigments and dyes. This is the ultimate direction that this project will be moving toward. Nanoparticles used as bio tags for an unprecedented level for cellular targeting eliminating the need to use the conventional methods of bio staining.

Reference:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC419715/

*UPDATE* 3/11/2017 4:55AM

The LS-532A-laser collimation tube assembly, is my design and build. I have assigned it this nomenclature for easy identification.

Here are the three components that will be a critical part of the CCD driver circuit, so I wanted to post a general feature and description of them, starting with the AD8021 opamp (which will be used as the pre amp for the ADC (AD7667)

GENERAL DESCRIPTION

The AD8021 is an exceptionally high performance, high speed voltage feedback amplifier that can be used in 16-bit resolution systems. It is designed to have both low voltage and low current noise (2.1 nV/√Hz typical and 2.1 pA/√Hz typical) while operating at the lowest quiescent supply current (7 mA @ ±5 V) among today’s high speed, low noise op amps. The AD8021 operates over a wide range of supply voltages from ±2.25 V to ±12 V, as well as from single 5 V supplies, making it ideal for high speed, low power instruments. An output disable pin allows further reduction of the quiescent supply current to 1.3 mA.

*UPDATE* 3/27/2017 5:54:AM

I eliminated the MAX232EIN from the circuit equation, it cannot handle the load placed on it from the AD8021 op amp, so it is going to be replaced by the MAX660 - Switched Capacitor Voltage Converter. The MAX660 CMOS charge-pump voltage converter is a versatile unregulated switched-capacitor inverter or doubler. Operating from a wide 1.5-V to 5.5-V supply voltage, the MAX660 uses two low-cost capacitors to provide 100 mA of output current without the cost, size and EMI related to inductor based converters. With an operating current of only 120 µA and operating efficiency greater than 90% at most loads, the MAX660 provides ideal performance for battery-powered systems. MAX660 devices can be operated directly in parallel to lower output impedance, thus providing more current at a given voltage. The FC (frequency control) pin selects between a nominal 10-kHz or 80-kHz oscillator frequency. The oscillator frequency can be lowered by adding an external capacitor to the OSC pin. Also, the OSC pin may be used to drive the MAX660 with an external clock up to 150 kHz. Through these methods, output ripple frequency and harmonics may be controlled. Additionally, the MAX660 may be configured to divide a positive input voltage precisely in half. In this mode, input voltages as high as 11 V may be used.

http://www.ti.com/lit/ds/symlink/max660.pdf

AD7667

FEATURES

2.5 V internal reference: typical drift 3 ppm/°C Guaranteed max drift 15 ppm/°C Throughput: 1 MSPS (Warp mode) 800 kSPS (Normal mode) 666 kSPS (Impulse mode) INL: ±2.0 LSB max (±0.0038% of full scale) 16-bit resolution with no missing codes S/(N+D): 88 dB min @ 20 kHz THD: –96 dB max @ 20 kHz Analog...

Read more »

NEW CCD update code may3.txt

*Updated FIRMWARE for 16 bit CCD driver circuit. 5/14/2017

plain - 4.88 kB - 05/14/2017 at 08:41

Download

ad7667-spectrograph-r1-gerbers.zip

fixed the two problems above in the design files. The 2-transistor isolation circuit is now on the board. The DesignSpark Project Files are now updated.

x-zip-compressed - 54.77 kB - 05/04/2017 at 10:40

Download

1tcd1304dg data sheet apr30.pdf

This is the data sheet for the TCD1304DG CCD chip

Adobe Portable Document Format - 316.20 kB - 04/30/2017 at 23:45

Preview Download

3d-printable-raman-spectrometer-BOMapr27 new one.xlsx

This is the BOM for the TCD1304DG driver circuit component section. 4/28/2017

sheet - 13.14 kB - 04/28/2017 at 11:39

Download

Spectral-Database-1.0-master (3).zip

This is the latest installment to my spectral database on github, there are now 125 absorption and emission scans. PNG pics are also included relative to the particular studies being done.

x-zip-compressed - 3.19 MB - 04/15/2017 at 14:16

Download

View all 21 files

  • 1 × Cuvette Holder W/ Exit slit plate Dimensions; 45 X 45 X 25 mm / 3D-printed by Sculpteo
  • 1 × (2) Square Mirror Mounts 26 X 13 X 26 mm
  • 1 × Round standoff M3 Nylon 13mm
  • 1 × Round standoff M3 Brass 11mm Used for enclosure
  • 1 × Machine screw Pan head phillips M3

View all 18 components

  • Atmega 2560 Triple Turret Stepper Motor Control Circuit Board

    David H Haffner Sr2 days ago 2 comments

    This is REV B of my Mega 2560 stepper Motor control circuit driver control board, I had to fix the switches as they were not working properly, now they do since I debounced them, I am posting a YouTube video showing it's operation


    Below is the Arduino breadboard schematic showing the entire layout;

    Next is the Fritzing schematic;

    Here is the schematic for the LM350T voltage regulator;

    Next is an Arduino barebones breadboard layout;

    A 4 panel snapshot view;

  • *Update* V3.01 Raman Spectrometer Prototype Redesign Works!

    David H Haffner Sr4 days ago 0 comments

    My next post will be the data specs for the CCD driver circuit, yes, it works...Yippie! I had to place the circuit board back in my prototype testing platform for now, until I can find an appropriate enclosure, I wanted to 3D print one but it is way to big and very expensive, unless someone has a better idea I am open to it!


  • 28BYJ-48 Stepper MTR/Triple Grating Turret Control Assembly prototype design 1(a)

    David H Haffner Sr05/11/2017 at 19:01 0 comments

    I've been working on this concept for awhile on the side for this project, it's incorporated directly into the Czerny-Turner configuration. Most of the prototype is on a 590 pin breadboard with an LCD screen (1602-C) to display data output., motor control, speed and temp ect.,

    Here is the concept below with an explanation for each panel:

    This is the voltage regulator that I am using to power the entire control circuit, it uses an LM350-T voltage regulator with an adjustable pin#1 (GRN) and a 217K resistor at pin#2 so it can be adjusted from 1.2vdc to 9vdc at close to 0.9A. with ripple rejection and circuit protection diode.

    This is a view from the power supply section of the board

    Here is the basic design concept, Czerny-Turner Configuration with a few more add-on's for a cleaner and more stable Raman signal (addition of beamsplitter/Dicrotic mirror) The turret sits of course between the 2 focal mirrors, it has 3 sides with different varying degrees of diffraction grating, example panel below;

    By rotating the turret, you can choose specific wavelengths

    This is the LCD display screen, I have code written to display MTR speed but I'm trying to figure out how to incorporate a more specific menu so I can track temp, and position.

    The proto board as it stands now

    I was never an artist so please forgive me, this is a crude mock up of the turret and the specs for the motor and it's drive steps, I'm just wondering if the Atmega1284 can handle additional control commands into memory and still have enough breathing room to operate without crashing or latching up?

  • (ADC) AD7667/A Mounted on 48 pin Schmart Board W/New Heatsink

    David H Haffner Sr05/06/2017 at 16:58 0 comments

    Parts are in for the new updated circuit board for the CCD drv board, so I put together the 48 pin AD7667astz chip with the new heatsink mounted on it and the results are really good.

  • *Heat Sinks Added To TCD1304DG/AD7667A (ADC) for CCD Detector...

    David H Haffner Sr05/05/2017 at 19:14 0 comments

    I got the idea for the heat sink for the TCD1304dg chip from @esben rossel he recently had a post where he showed how he cut a piece of aluminum block to act as a heat sink for the TCD1304 chip. That got me thinking, and so I formed my own aluminum heat sink out of aluminum industrial tape and will post the procedure also in my build files.

    Also I found the perfect heat sinks for the AD7667 (ADC) chip, these little 15 x 15mm aluminum heat sinks are used in a kit for the Xbox 360, for the RAM chips inside, it cools them between 10-12 deg F. Perrrrrrfect :)

    Here is the magic below;

  • **Updated Schematics** for CCD Driver Circuit/BOM/ 3D Printable Raman Spectrometer

    David H Haffner Sr05/03/2017 at 12:28 0 comments

    Here is the updated schematics for the CCD/TCD1304DG driver circuit and an updated BOM also.

  • Major Circuit Board Re-design/ Updated Gerber files and Design Spark project files

    David H Haffner Sr05/02/2017 at 21:41 0 comments

    I have been working with David Allmon on this CCD driver circuit for a couple of months now and there seems to be a unique problem with the circuit and I do not want to prematurely post the results nor post erroneous build files so there needs to be some explanation and also some help from anyone out here with mucho experience in electrical engineering, especially with ADC circuit design and operation.

    Apparently, David Allmon didn't have this problem until he started using the AD7667 ADC, even though the data sheet calls for the AD8021 op amp as it's pair up component. We have been kickin' ideas around and this guy is brilliant no doubt, I just think the more grey matter on this the better, it would be so greatly appreciated!

    Well here is part of the problem;

    "The ADC is prone to latchup when OVDD is brought up at the same time as DVDD. OVDD needs to be off until DVDD has reached 2.4V or so. There is a fix for this. I cut the trace around pin 18 of the ADC in two places to isolate it from the 5V supply. Then I run a wire from pin 1 of the ATmega1284 to pin 18 of the ADC. A little firmware tweak and the OVDD line is controlled by the MCU, which brings OVDD up after its own 5V comes up. OVDD on the ADC only draws around 200µA, so it is safe to power through the MCU. OVDD is the voltage supply for the MCU interface on the ADC.

    Even though Dave made the fix for this both on the board and in the firmware, there can still be a problem with latchup if you have the USB plugged in before powering up the board. The board will be powered by the current going through receive line and the protection diodes. It will be powered and the MCU can't prevent latchup on power up. Not sure why. It is probably already latched up at that point. On all boards I do with a USB-TTL converter I have begun putting a 2-transistor buffer that leaves no path for the USB-TTL transmit line to get to VCC."

    Ok, so that's that little tidbit. Here is the link to his website for the full explanation; http://davidallmon.com/pages/ad7667-spectrograph - board re-design and circuit changes

    Also you will find the new gerber files and Design Spark project files there also, I will have them available here and on Github also.

    Ok so that's the status update we are workin' hard on this but it never hurts to get a little help from UR friends!

    Thanks David H Haffner Sr :)

  • ATMega1284P Dev Board

    David H Haffner Sr04/29/2017 at 17:57 0 comments

    This is the latest pics of my Dev board with the ATMega1284P chip;

    Available at Tindie.com but comes with the ATMega32 chip already installed and ready to go.

  • BOM for The TCD1304DG Driver Circuit/ATMega1284P

    David H Haffner Sr04/27/2017 at 21:45 0 comments

    *UPDATE* 4/28/2017 7:35AM

    I updated my BOM and included a "comment" section at the end that gives a description of the component as it relates to the part # for better clarification, and uploaded a csv file version in my files section for you to download.

    @Sophi Kravitz Hipped me to a great tool called FindChips, she may have sent individuals the email already, but I went ahead and created the BOM for the driver circuit for the CCD detector. What an easy way to create a BOM!

    Here is the link for my BOM...

    http://www.findchips.com/u/list/28511-3d-printable-raman-spectrometer

    :)


  • 1616 Research Lab Files for the DH4.0 V4 DAV5 V2 and DAV5 V3 Spectrometer

    David H Haffner Sr04/24/2017 at 23:59 0 comments

    I have uploaded 1616 files from Jan 2016 - Oct 2016, which encompass all documentation relating to my first spectrometer build the DH4.0 v4 to the DAV5 V3 and all related absorption and emission spectra and excell files, PNG pics and data tables ect.,

    The zip file is 83MB (quite large,) but a lot of information contained there in, even all my CAD files for the DAV5 V3 Raman spectrometer build. I still have about 9000 files left to go and trying to figure out a better platform for organizing the info like the NIST uses and others for data acquisition and downloading.

    I feel this is important work, because it demonstrates the viability of citizen scientist and hobbyist's building instrumentation such as this and acquiring the same quality scientific results as the professionals do.

    So this zip file is available only at my open source website at http://osf.io/x9gm6/files/

    Just scroll down to were it says; "google drive files," and you will see it.

    In process of enclosure re-design to accomodate the TCD1304DG detector ( the board dimensions are 100mm x 100mm) no way around it, both analog and digital circuitry are located on same board. I could not extend the PGM (serial port) because the TCD1304 does not behave properly and can be damaged by extending wires beyond 4".

View all 94 project logs

  • 1

    These are the build instructions for my LS-532 CB/fiber optic laser collimation tube;

    New Holographic diffraction grating holder assembly.W/drawings:

    The newly re-designed parts came in so I began to prep them and wanted to include them here under build instructions;

    These are the first preliminary drawings and CAD blueprints depicting several aspects in the assembly design and by no means is this the final assembly steps;

  • 2

  • 3

    10X Lens Holder Base assembly and holder design W/ slide rail feature:

View all 13 instructions

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Discussions

David H Haffner Sr wrote 03/09/2017 at 12:26 point

@fl@C@ , I did not mean to offend your project, my thoughts about your methodology are just my opinion, not a rant about my superior intellect. You made a few bold claims about your devices capabilities and did not provide enough documentation to support them, that's all I was getting at. 

In the scientific spectrum, there is always a clear trail of evidence that others should be able to follow in order to verify claims made, and to all experiments. 

Your project is quite extraordinary,

no doubt, but there are several flaws in some of the capabilites that you claim that it can do. As far as utilizing some of your design concepts, very few, the 3D prints are my own design, the Czerny-Turner configuration is just good science, the CCD detector and MCU, are NOT your design, so get over that. 

The .src code I am using is not yours either. When I talk about "full" documentation, that's exactly what I mean, not only the mechanical side of things, but the chemistry and spectroscopy side of things also...The process, that's what is important. Yes, the long boring techy stuff, the stuff like, what standard did you use to calibrate and verify your spectrometer? Did you use holmium Oxide?

Because when all is said and done, that is what I'll be using (and I'm going to have to make the $$ sacrifice of about $450.00US,) to verify that my spectrometer is on point and ready to go. I'm not recommending that anyone else has to do this, I'm doing it because I want this project to reflect my commitment to excellence.

Let me explain once more this projects details:

The DAV5 V3 Spectrometer will be the only project build here on Hackaday in its category, with ongoing, full performance and specifications documentation, this project will also be at least 95% 3D printed! The main goal for this project has 4 points: 

1) To build a rugged and reliable low cost spectrometer with 3D printable parts. 

2) A spectrometer capable of producing consistent and professional quality results in the field, home or Lab 

3) A device with upgradeable capabilities 

4) Every part of this project will have it's .STL file (for 3D-printing,) available for download. 

**This project will also have full professional/analytical and chemical documentation.

**Also as an aside, I have owned my Aries 532nm Green laser (150mW) for over 4 years,) so I did not rip that idea off either.

  Are you sure? yes | no

Loki wrote 03/03/2017 at 12:07 point

Especially with many cell phone cameras enabling access to RAW format images from their cameras (iPhone 6 and newer, many androids), is there any reason not to skip the CMOS all together, and use a cellphone camera; and also use it for the image processing?  Essentially, just have the light source, slit, diffraction, and raman filter in this device, and design it to mate to a cell phone camera?  That would give 8MP+ of resolution.

  Are you sure? yes | no

David H Haffner Sr wrote 03/03/2017 at 12:23 point

Well Loki, the problem with that idea is, cmos has a spectral limit of 1100nm, (metal oxide,) Raman spectroscopy requires a set up like the Czerny-Turner configuration. Also you need a stable laser source coupled with an appropriate bandpass filter.  

  Are you sure? yes | no

Loki wrote 03/03/2017 at 12:54 point

I think that's what I just said.  When I said "device", I meant external device: all the parts of this project (or the Montoya one), except for the CMOS camera and image pipeline.

  Are you sure? yes | no

David H Haffner Sr wrote 03/03/2017 at 13:01 point

"and design it to mate to a cell phone camera?  That would give 8MP+ of resolution."
you stated the above though, and that's what I was going by, if I misunderstood sorry.

  Are you sure? yes | no

Loki wrote 03/03/2017 at 13:07 point

No, that is correct.  Instead of using an older DSLR such as is used in the Montoya design, use a modern cell camera.

Could you explain more about why the CMOS spectral limit is a problem?  perhaps that's what I don't understand, in light of a CMOS sensor being successfully used in the Montoya design.

  Are you sure? yes | no

David H Haffner Sr wrote 03/03/2017 at 14:18 point

It all comes down to photons interacting with silicon. cmos if you are not familar, are 1000's of microscopic photo diodes, photons with an energy above 1.1eV will not necessarily interact with silicon. Their probability interaction depends on how much higher than the 1.1eV band gap the energy of the photon is, this defines an absorption coefficient  [cm-1] depending on the wavelength and the type of material.

This absorption coefficient defines which percentage of the photons entering a one centimeter material will be absorbed. 

To make it even simpler, silicon as a material substance, will only by its own nature, absorb so many photons no matter what, and it just so happens that the limit is approximately 1125nm.

So, as long as you are willing to stay around the 400 - 700nm range in the spectrum you'll be fine...see my point?





  Are you sure? yes | no

Loki wrote 03/03/2017 at 14:32 point

If we're going for stokes raman:

"Raman signals excited by a 532nm laser are distributed in the visible range, where the response is best for most silicon-based CCD chips. Meanwhile, Raman signals from 785nm systems fall within the NIR range (750-1050nm), where the response is still relatively good. For 1064nm, however, typically there is no response from the CCD above 1100nm" (http://bwtek.com/wp-content/uploads/2015/07/raman-laser-selection-application-note.pdf).

As long as we use a 532nm laser, the resulting stokes radiation we need to detect stays in the visible range - which would seem to allow for the use of a CMOS camera.  Also, to get around issues with low signal intensity, why are people sticking with 150mw range lasers, when so much higher power lasers are available for approximately the same cost?

  Are you sure? yes | no

David H Haffner Sr wrote 03/03/2017 at 15:07 point

Yes, you are correct about that, as I stated; as long as you stay within the boundaries of 400-700nm, a 532nm CW laser at at least 150mW will work. The reason I changed up my design scheme was that at 532nm for that particular set up would not have been very effective for analytical Raman spectral work of liquid mediums.

This type of Raman spectroscopy works best at the reflectance level, and I just didn't want to drastically re-design the whole system to accommodate it. Too many more parts and 3D printed parts, more headaches :( 

Ok, typical 785nm Raman spectroscopy is just NOT feasible for a cmos camera, after 700nm the spectrum gets very "scraggly," unpredictable and very unusable. http://www.aphesa.com/documents.php?class=wp - click on the pdf file that says; "Spectral Response of Silicon Sensors"

  Are you sure? yes | no

finstp wrote 02/28/2017 at 21:57 point

There is a very simple design for a home-made 3D printed Raman spectrometer in the literature, complete with very nice example spectra.

See 'A Homemade Cost Effective Raman Spectrometer with High Performance' by EH Montoya, A Arbildo and OR Baltuano published in Journal of Laboratory Chemical Education 3(4) p 67-75, (2015) doi:10.5923/j.lce.20150304.02. This could easily be coupled with the Spekwin32 software (see here on Hackaday), which can extract a linescan spectrum from the digital camera image and you have all the benefits of professional software too!

  Are you sure? yes | no

Michael Stone wrote 01/18/2017 at 01:32 point

This is actually really really awesome. Battelle is a defense contractor here in the states, they sell a biohazard detector that is pretty large for a lot of money, this thing can be made for a fraction of that cost and easily applied to do biohazard detection. Great work!

  Are you sure? yes | no

David Challener wrote 01/13/2017 at 19:19 point

I have been looking at Raman designs, and they all seem to have beam splitters in them. but I don't see one in your design. I have never been really sure why there was a beam splitter in the first place, so perhaps it isn't needed, but I don't understand why anyone would reduce the amplitude of the reflected light by a factor of 2 if it were not needed.  Additionally, Is more lines better or worse? (I can get a good 2500 lines per mm for $26).

  Are you sure? yes | no

David H Haffner Sr wrote 01/13/2017 at 19:56 point

Hey David, first, the more lines per mm the higher the spectral resolution, but will "reduce" your wavelength range, so when choosing a higher order grating you have to make sure you know what wavelength your working in.

1200 lines is perfect when using Holographic gratings or high quality ruled blaze angled gratings, the DVD piece is fine at 1540 lines, mostly because some of those lines are not placed so perfect during manufacturing, but there are enough good lines that are parallel where the diffractive properties are just fine, (hence the Schott glass color filter.)

Second, beam splitters, especially the cube type, are used to separate wavelength and power distribution of the laser's collimated light, in the case of Raman spectroscopy, it is used because in most set ups, there is an adjustable diffraction grating that can be rotated to select a particular wavelength. 

I don't have to use it, although it certainly would improve the overall sensitivity of my system but then it will start to become very complex and costly and since I am only concerned with the region between 500-4000 cm -1 (546.5 - 675.6nm,) I am confident all will be well. 

I know it may seem a bit strange why you would want to attenuate the incoming light beam, but depending on the application, you may want to only have 45% transmission 55% reflectance or aligned for maximum p-polarized transmission (99% reflected - 1% transmitted.) 



  Are you sure? yes | no

David H Haffner Sr wrote 01/13/2017 at 20:05 point

Also I wanted to add a quick note, mine has a secret weapon; 532nm, 12.5mm Diameter, Raman Edge Filter. http://www.edmundoptics.com/optics/optical-filters/longpass-edge-filters/raman-longpass-edge-filters/86225/

  Are you sure? yes | no

Ryan White wrote 01/23/2017 at 11:07 point

There ya go, that's what's up, but you've gotta hold your laser on that wavelength, and your laser needs to be single mode, what's your source?

  Are you sure? yes | no

David H Haffner Sr wrote 01/13/2017 at 08:38 point

Hey Ted, for an application such as this one, I would use a UV Reflective Holographic Grating, 1200/mm. Cost is around $131.00US, depending on the source and quality.

Also I wanted to add that, Holographic gratings have a low occurrence of periodic errors, which results in limited ghosting, unlike ruled gratings. The low stray light of these gratings makes them ideal for applications where the signal-to-noise ratio is critical, such as Raman Spectroscopy.

I am hoping that the Schott glass color filter placement with the diffraction grading placed before the spectral image strikes the detector, will eliminate the stray light and most ghosting effects, if not, I will be forced to adapt and use the holographic grading, which will cause a slight re-design and significant up-cost.

  Are you sure? yes | no

David Challener wrote 01/12/2017 at 22:56 point

So next question - why are you using a DVD for your diffraction grating?  I see them used in very low cost spectrometers, but they clearly aren't quite parallel lines.  Does this matter?

  Are you sure? yes | no

David H Haffner Sr wrote 01/12/2017 at 23:53 point

Hey David, good question, I'm using the 4.7G DVD piece with 1540 lines per mm. Spectral resolution is more important than how straight the lines may be on the diffraction grating, I've been researching this aspect for over a year now and I know that it does work, you just have to be willing to be patient and rotate the grating carefully until the spectral lines are straight.

I explained how to do this in a previous log and in some research notes on Public Lab. That is also why I cut the piece 18 x 18mm square and placed each corner on the flat top end of the Schott glass filter locking sleeve, so it can be rotated as you are watching the spectral lines in live capture mode on screen. 

I use a 2300K 13W CFL (compact fluorescent light) to calibrate the diffraction grating piece because of the mercury lines.

I hope this explanation helped!



  Are you sure? yes | no

David Challener wrote 01/11/2017 at 17:14 point

I am interested in building one of these.   Is it ready to go?

  Are you sure? yes | no

David H Haffner Sr wrote 01/11/2017 at 17:29 point

Hey David, everything is ready except the Raman longpass edge filter, I will not be able to purchase it until sometime next month, I included it on the bill of materials because it certainly needs to be there.

The rest of the device is performing beautiful in the UV/VIS range-300-800nm. It will do absorption/fluorescence and UV as it stands at this moment.

  Are you sure? yes | no

PointyOintment wrote 01/10/2017 at 09:22 point

> The DAV5 V3 Spectrometer will be the only project build here on Hackaday in its category

Even if the category is as narrow as "open-source 3D-printed Raman spectrometers", there's already another project in it: #ramanPi - Raman Spectrometer

  Are you sure? yes | no

David H Haffner Sr wrote 01/10/2017 at 11:38 point

Hey pointyointment, yes that is true, but the Ramanpi project's main documentation is mainly centered around the 3D printing of their design and on their concept of home automation. Proving their concept is very questionable for such bold claims.

They do not have sufficient scientific documentation validating the Raman aspects of their device. The process for doing so is very meticulous and precise and must be done with caution, scientific claims must be able to stand up to intense scientific scrutiny by your peer community and not be prefaced by popularity.

My project has intentional and methodical steps and protocols in order for clear validation, when I am ready to capture Raman signals that will be a whole separate set of steps and protocols.

Also, my project includes cost analysis for full transparency, in order to keep the projects main goal under $700.00US. The average cost even for a 3D printed version of high sensitivity and precision can cost upwards of $2500.00 to 3000.00US Total.

  Are you sure? yes | no

Ted Yapo wrote 01/13/2017 at 00:35 point

Do you know approximately how much cost it would add to the BOM to use a commercial replica grating instead?

  Are you sure? yes | no

fl@C@ wrote 03/09/2017 at 11:00 point

I would have hoped that you would have contributed to, instead of insulting a project that clearly inspired not only the name of this project, but the design as well..  Although, after reading your replies to most of the comments here.....It doesn't sound likely that your input would be very useful when taken as a member of a group, rather than you taking credit and imposing your superior knowledge on everyone.  If your understanding of ramanPi is limited to the thought that it is centered around home automation, maybe you should review the documentation again.  It's quite interesting that you seem to have chosen many of the same components, for such a questionable concept... 

  Are you sure? yes | no

Jarral Ryter wrote 01/05/2017 at 21:28 point

yes raman has some sort of light scattering by shining laser onto the sample.... maybe you made a fluorescence spectrometer. Which is still cool.

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David H Haffner Sr wrote 11/24/2016 at 14:47 point

Hey Ryan, that's a good question, and I'm glad you asked it. Most Raman spectrometers are usually quite large and have very complicated optical designs, but the basic operating principle is still the same, resolving power of the optical mirrors and lines per mm on the diffraction grating.

A raman spectrometer can be composed of either a CCD or a CMOS detector, I have worked for a year researching the cmos type, and that is why I am using it, (cmos,) I am experimenting with the use of only one mirror, the square silver coated focusing one. The optical resolution of the spectrometer is determined by the input slit size and the optics inside the spectrometer. The best possible resolution that can be obtained is the diffraction limit, which is the resolution obtained with an infinitely small input slit. The diffraction limit is related to the size of the beam width inside the spectrometer.

The wider the beam, the more grating lines the beam illuminates and, therefore, the better the resolution. This is also referred to as the resolving power of the grating.

I will be posting a more detailed explanation of the theory and concept of my design, and the mathematics to back it up, plus I have research to back up this design also. So Raman merely means the resolving power of the spectrometer to clearly define the spectral lines with precise definition for accurate molecular finger printing.

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Ryan White wrote 01/23/2017 at 11:03 point

OK, but, Raman spectrometers use high intensity laser sources and look for the signature in the Raman shift of the scattered light, right? So basically you're looking for very weak signals very close to, but not at, the wavelength of the light source. 

Raman spectrometers use laser sources of very high spectral purity (i.e. narrow spectral line width, low phase noise, whatever you want to call it) and very narrow band filters, and as far as I understand it both are tunable, you don't seem to have either. "modern instrumentation almost universally employs notch or edge filters for laser rejection and spectrographs either axial transmissive (AT), Czerny–Turner (CT) monochromator, or FT (Fourier transform spectroscopy based), and CCD detectors." - https://en.wikipedia.org/wiki/Raman_spectroscopy

This, as far as I can tell, is not a Raman spectrometer.

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Ryan White wrote 01/23/2017 at 11:05 point

I've just seen your more recent comments, I'd love to see this working and I'd love to see how you're controlling the wavelength of the laser source. 

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David H Haffner Sr wrote 01/23/2017 at 11:43 point

Ok Ryan, my laser is a CW (continuous wave,) 150mW DPSS, I have posted the specifications for it here many times, I have a 532nm CWL, 10nm FWHM, 25mm bandpass filter employed in my fiber optic laser collimation tube assembly, I have already stated in previous postings that I am waiting on my 532nm, 12.5mm Diameter, Raman Edge Filter, it costs $450.00US, I am not made of $$.

I never stated it was a Raman spectrometer YET, it will be by the time I am finished, I strive for perfection, not speed or popularity. I do NOT need a CCD to detect Raman signals.

Finally, I am not going to explain myself over and over again, when I have been quite clear in my research and documentation, not only about Raman spectroscopy, but spectroscopy and chemistry itself. Read my work.

 

  

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Ryan White wrote 01/23/2017 at 11:48 point

Good luck with it! I'm watching with interest because I know how hard this stuff is, not because I think you won't do it. The internet is bad at capturing my tone, and (as I'm sure you know) there's been a lot of bullshit merchantry around handheld raman spectrometers for all kinds of applications, hence my skepticism. 

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Ryan White wrote 01/23/2017 at 11:52 point

Nice write-ups as well, looking forward to seeing the results (and building one!) 

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Ryan White wrote 11/24/2016 at 13:37 point

How is this Raman? 

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