Oil testing kit Blog



Oil Testing with the Green Team

by stevie | about 9 years ago | 1 | 3

I have been working to refine the workshop that will support the new Public Lab Oil Testing Kit. To test out the existing format, I spent two afternoons with Groundwork New Orleans' Green Team - a great group of enthusiastic high school students. We've been running the Beta program for the past couple months, and so alongside the workshop format, I ran a version of the beta program for the students to contribute to. In this post I will include some of our experiences building the kit, taking some samples and reflect on the workshop format.

Building the kit

I had two, two hour blocks of time to run the workshop, so we spent the first day on kit construction. The students worked in pairs on building the spectrometer 3.0 and accompanying oil testing add on pieces. The construction of the spectrometer went really smoothly. The students enjoyed working on it and were able to do it fairly quickly, faster than I saw groups do it when I ran a workshop at the maker space a few months back. Part of this could have been because the instructions are a little more refined online. One hiccup we ran into was people assembling the box wrong, so that the hole for the camera cord was not in the right place, but this was easily fixable.

The students had more trouble assembling the oil testing kit than the spec. Everyone ended up using @mathew's research note for assembly, but did experience some difficulty:

  • There was confusion on the long thin piece that turns into the M and holds the laser in place. The students were unsure if the sides of the M should sit inside our outside the box.
  • The piece that I've since been referring to the "stingray" was difficult to figure out how to fold. None of the groups were able to figure it out on their own.
  • The oil testing add-on required a good bit more finagling to assemble than the spec. We ended up needing to cut the V shaped laser holder to get things to fit properly.
  • The slits on the box that holds the V piece down on either side were difficult to get the tabs into. We needed up crumpling several of the V pieces by accident.
  • The group recommended that a video on folding these pieces would be really helpful.
  • I recommend that we name the pieces so they are easier to refer to both on Public Lab and in a workshop setting.

20151027_163139.jpg

Scanning samples

We devoted the second day of the workshop to scanning samples. We all found the Chrome browser worked the best for us in scanning. Here are some things we struggled with:

  • We had trouble getting the laser light to match up with the sample. We ended up taking out the sample holder and having one person on each team hold the sample by hand in order to get the light at the right angel. (as a side note, in previous kit construction, I did not have this problem, I'm not sure why we did this time, but we had to take the sample holders out of all 3 kits).
  • On spectral workbench, some of the students had a hard time telling when they were taking a sample and when they had saved it. A walk through from logging in to scanning a sample and adding it to a set would be really helpful, much like the one you can watch on mapknitter.org.
  • It took a long time for us to get one or two good scans, we defiantly needed more time and a different sample holding system to refine this.

Here are some of the things that went well: - Working in pairs was a good idea both in construction and in taking the samples. In scanning the samples, one student ran the computer and one managed the sample and the laser. - All of the groups were able to scan the 80w90 and the North Dakota Crude. However, the varying laser light and ability to hold the sample still made it so only about 1/4th of the scans were useable.

Workshop reflections

I'll be editing the workshop page in the next day or two with more technical changes, but below are some general reflections.

  • Make sure all the computers run spectral workbench, I had to instal different browsers to make this run more smoothly (Chrome worked best).
  • Don't calibrate anything until both pieces of the kit are constructed, then calibrate the spec and put them together. Breaking up kit construction with calibration ruined the flow the group had on construction.
  • While many of the students enjoyed putting the spec together, they all enjoyed running the samples.
  • We needed one more 2 hour time slot to really scan all the samples and refine our scanning techniques.

Interested in catching up with students from the Green Team about this project? Look for them at the Barnraising!

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Oil Testing Kit -- Assembly & Calibration!

by _mahsa_ | about 9 years ago | 4 | 5

Hi, I'm Mahsa a member of the Oil Testing Kit beta program and below you'll find my experience assembling the oil testing kit.


Contents

Here are the contents to make the spectrometer and the cuvette frame:

IMG_20151012_211406069.jpg IMG_20151012_224916886.jpg


Spectrometer Assembly

I found @Cindy_ExCites post on the spectrometer assembly incredibly helpful, as are the online public lab directions (it was really hard to tell what was going on in the black and white photos that came with the kit -- I wish I had realized earlier that the directions were online with color photos!).

Since there are already comprehensive steps online, I won't go into step by step directions and instead share a couple photos I snapped during the process.

Attaching the camera to the block:

IMG_20151012_212953362.jpg
I would definitely recommend using 2 pieces of tape when attaching the camera, I didn't initially do this but ran into issues of the camera moving sideways when I started using the spectrometer. I got the idea from @Cindy_ExCites and here's their photo of it:

IMG_2213.JPG


Making the diffraction grating from a DVD:

IMG_20151012_213726230.jpg
Putting all the pieces together and placing it into the frame:

IMG_20151012_223417524.jpg

IMG_20151012_223931853.jpg


Extra pieces, one looks important but I couldn't figure out where it should go...

IMG_20151012_223948522.jpg


Cuvette Frame Assembly

This part was a bit more complicated and time consuming. A glossary would've been helpful -- it took me an embarrassingly long time to realize what a 'cuvette' was! Again the black and white pictures in the directions that came with the kit were very hard to see and figure out where the folds were. If the pieces were light colored on one side and dark colored on the the other the contrast might have helped in figuring out where the folds were.

Again, @Cindy_ExCites post was incredibly helpful and even with their directions I struggles with "the M-folded sheet" piece. I made the same extra cuts @Cindy_ExCites did in it -- this is their photo of it:

IMG_4040.JPG

Slits I cut into my piece:

IMG_20151012_230011033_HDR.jpg

Even after reading about @Cindy_ExCites placing the v-folded strip in the wrong way, I made the same mistake and it was a pain to get out. Here are some notes that might help others in figuring out the placement of the v-strip in relation to the m-piece:

IMG_20151012_232530574_HDR.jpg

The first time I assembled the cuvette holder, I had the little square in the middle popped up the wrong way, which resulted in the cuvette standing too high up. Here I'm pointing to the little square popped out the WRONG WAY:

IMG_20151108_112331451.jpg

and here it is popped out the CORRECT WAY:

IMG_20151108_112416695.jpg

Here you can see it popped out the right way and holding the cuvette:

IMG_20151108_112707106.jpg

Attaching the cuvette holder to the rest of the frame was a bit tricky. It was hard to tell where the flaps should go. @Cindy_ExCites has some good photos. One thing that wasn't apparent at first was that the long flap should be inserted into the crease of the holder (pink arrow) and then back thru a slit into itself (blue arrow). Hard to describe, but maybe this picture helps:

IMG_20151108_101806546.jpg
Completed!

IMG_20151108_115353049.jpg


Calibrating

@Cindy_ExCites post was really helpful. Similar to them, I had to adjust the DVD. I also realized that the camera had shifted at this point and that's when I decided to apply a second layer of tape to stabilize it.

As for calibrating, I haven't been successful at getting it to work. My first couple tries I got an error that the spectrum is overexposed. For example: cfl.png

I tried using a warm compact florescence bulb, a cool bulb, a plastic bag over the spectrometer, and pointing it at different distances and still couldn't get it to work. Whenever the red and green levels were not overexposed, the blue didn't have peaks, like this:

clf2.png

Here are all my attempts: calibration 1, calibration 2, calibration 3, calibration 4, and calibration 5

I'll give it another try and update soon...

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Oil testing kit Beta programme - Technical adjustments (hack!)

by cindy_excites | about 9 years ago | 2 | 3

Oil testing kit Beta programme - Technical adjustments to Public Lab Spectrometer 3.0

Date: 4/Nov/2015

Here I document my experience making adjustments to the Public Lab Spectrometer 3.0, which was assembled using these instructions.

Propping-up the cuvette holder and aligning the spectrometer

When I started scanning the Mineral Oil sample [ HYPERLINK HERE ] no light was being captured. I separated the cuvette frame and spectrometer and I noticed that the laser beam was not passing through the centre of the 'viewing window' in the cuvette holder:

IMG_4166_misalligned.JPG

I then noticed that the slit in the slit card of the spectrometer did not aligning correctly to the 'viewing window':

IMG_4167.JPG

I devised a support structure to prop-up the cuvette holder using small Lego parts:

Technical_issues--_IMG_4160_-_lego_piece.JPG

I inserted the Lego structure under the cuvette holder…

Technical_issues--_IMG_4162_-_lego_placement.JPG

…so that the cardboard rests between the Lego brick 'protrusions' (what are these circular things called?)

Technical_issues--_IMG_4163_-_lego_piece_in_place.JPG

Propped-up, the cuvette frame now looks like this:

Technical_issues--_IMG_4158_-_lego_final_look.JPG

The final adjustment - due to lack of time - was to keep the cuvette frame and spectrometer holding tightly and steadily together. I used mammoth tape, which does not stretch nor damage the cardboard yet can still be easily removed.

I taped the cuvette lid. I also taped the cuvette frame to the spectrometer in two places: on the side and at the bottom (not pictured here):

Technical_issues--_IMG_4164_-_frame_tape.JPG

Issues which I have not tackled:

1) The cuvette holder has enough room for the cuvette to move around. When I pushed the cuvette all the way to one side (left side looking towards the slit card from the cable feed) I got this…

Technical_issues--cuvette_positioned_left.png

…and when moved to the other side (right side looking towards the slit card from the cable feed):

Technical_issues--cuvette_positioned_right.png

2) The second issue is that the cuvette itself is ribbed on two sides and smooth on the other two. The spectrometer receives the light coming out from the ribbed side. I wondered if this makes a difference and it does: if the laser enters the sample through the ribbed side and the spectrometer captures the light coming out from the smooth side, more frequencies seem to be captured. I would like to test this further and post some photos in the future. For now I just wanted to point this out and ask if it this was perceived as non-problematic when choosing the cuvettes and/or the design of the spectrometer and cuvette frame and the way they fit together.

Related research notes:

Oil testing kit Beta programme - Package content

Oil testing kit Beta programme - Assembly: cuvette frame

Oil testing kit Beta programme - Assembly: spectrometer

Oil testing kit Beta programme - Calibration

Oil testing kit Beta programme - Scanning OTK samples

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Oil testing kit Beta programme - Scanning OTK samples

by cindy_excites | about 9 years ago | 5 | 3

Oil testing kit Beta programme - Sample scanning notes

Contributors: @TedF and @cindy_excites

Date: 4/Nov/2015

Here we document our experience using the Public Lab Spectrometer 3.0 (assembled using these instructions) to scan our Oil Testing Kit Beta samples, which arrived with our OTK packages.

1) Scanning Mineral oil

We begin by sampling mineral oil. First without laser attenuator:

Mineral_Oil.png

Mineral Oil similar matches (by clicking on the "Find similar" button):

Mineral_Oil_similar-matches.png

Then tested the Mineral oil with the attenuator:

Mineral_Oil_w_attenuator.png

NOTE: Unfortunately, we cannot accurately tell which gradation of attenuation we used as the attenuator slider is slid into the black cuvette frame. But perhaps this does not matter?

Then compared the two - without and with attenuator (by clicking on the "Compare" button):

Mineral_Oil_comparison-w-and-wo_attenuator.png

Mineral Oil similar matches (by clicking on the "Find similar" button):

Mineral_Oil_comparison-w-and-wo_attenuator-closest-matches.png

This exercise was most useful in familiarising myself with the different functions of Spectral Workbenck [ https://spectralworkbench.org/ ] and the different parts of the spectrometer. I also realised that the spectrometer had some technical issues, which I fixed using Lego blocks. [ HYPERLINK HERE ].

2) Scanning unknown sample # 26

We proceed to scan sample # 26 and we carry out three repetitions of the scan. For each rep I turned the cuvette around (to scan from the other side).

Note: For (nearly) all samples that follow I have created screen clippings for the capture page, the annotation pages, and the similar spectra page of each rep, as well as the compare all reps page.

IMG_4133_-_26.JPG

Scanning of sample # 26, rep a:

Scan_sample_26_-_rep_a.png

Sample # 26 similar matches for rep a (by clicking on the "Find similar" button):

Scan_sample_26_-_rep_a_closest-matches.png

Scanning of sample # 26, rep b:

Scan_sample_26_-_rep_b.png

Sample # 26 similar matches for rep b (by clicking on the "Find similar" button):

Scan_sample_26_-_rep_b_closest-matches.png

Scanning of sample # 26, rep c, capture page:

Scan_sample_26_-_rep_c_capture_page.png

Scanning of sample # 26, rep c - sample annotation:

Scan_sample_26_-_rep_c.png

Sample # 26 similar matches for rep c (by clicking on the "Find similar" button):

Scan_sample_26_-_rep_c_capture_page.png

Comparison of all 3 reps (by clicking on the "Compare" button):

Scan_sample_26_-_comparing_all_reps.png

3) Scanning unknown sample # 79

We then scan sample # 79 and we carry out three repetitions of the scan. Scanning of sample # 26, rep a:

IMG_4135_-_79.JPG

Scan_sample_79_-_rep_a.png

Sample # 79 similar matches for rep a:

Scan_sample_79_-_rep_a_closest-matches.png

Scanning of sample # 79, rep b, capture page:

Scan_sample_79_-_rep_b_capture_page.png

Scanning of sample # 79, rep b - sample annotation:

Scan_sample_79_-_rep_b.png

Sample # 79 similar matches for rep b:

Scan_sample_79_-_rep_b_closest-matches.png

Scanning of sample # 79, rep c:

Scan_sample_79_-_rep_c.png

Sample # 79 similar matches for rep c:

Scan_sample_79_-_rep_c_closest-matches.png

Comparison of all 3 reps for sample # 79:

Scan_sample_79_-_comparing_all_reps.png

4) Scanning unknown sample # 111

We continue with scanning sample # 111 and carry out three repetitions of the scan

IMG_4137_-_111.JPG

Scanning of sample # 111, rep a, capture page:

Scan_sample_111_-_rep_a_capture_page.png

Scanning of sample # 111, rep a:

Scan_sample_111_-_rep_a.png

Sample # 111 similar matches for rep a:

Scan_sample_111_-_rep_a_closest-matches.png

Sample # 111 similar matches for rep b:

Scan_sample_111_-_rep_b_closest-matches.png

Sample # 111 similar matches for rep c:

Scan_sample_111_-_rep_c_closest-matches.png

Comparison of all 3 reps for sample # 111:

Scan_sample_111_-_comparing_all_reps.png

4) Scanning unknown sample # 5w-30

Next we scan sample # 5w-30 and carry out three repetitions of the scan.

IMG_4140-_5w.JPG

Scanning of sample # 5w-30, rep a, capture page:

Scan_sample_5w-30_-_rep_a_capture_page.png

Scanning of sample # 5w-30, rep a:

Scan_sample_5w-30_-_rep_a.png

Sample # 5w-30similar matches for rep a:

Scan_sample_5w-30_-_rep_a_closest-matches.png

Scanning of sample # 5w-30, rep b:

Scan_sample_5w-30_-_rep_b.png

Sample # 5w-30similar matches for rep b:

Scan_sample_5w-30_-_rep_b_closest-matches.png

Scanning of sample # 5w-30, rep c:

Scan_sample_5w-30_-_rep_c.png

Sample # 5w-30similar matches for rep c:

Scan_sample_5w-30_-_rep_c_closest-matches.png

Comparison of all 3 reps for sample # 5w-30:

Scan_sample_5w-30_-_comparing_all_reps.png

5) Scanning unknown sample # 20w-30

Next we scan sample # 20w-30 and carry out three repetitions of the scan.

IMG_4141_-_20w.JPG

Scanning of sample # 20w-30, rep a, capture page:

Scan_sample_20w-30_-_rep_a_capture_page.png

Scanning of sample # 20w-30, rep a:

Scan_sample_20w-30_-_rep_a.png

Sample # 20w-30 similar matches for rep a:

Scan_sample_20w-30_-_rep_a_closest-matches.png

Scanning of sample # 20w-30, rep b:

Scan_sample_20w-30_-_rep_b.png

Sample # 20w-30 similar matches for rep b:

Scan_sample_20w-30_-_rep_b_closest-matches.png

Scanning of sample # 20w-30, rep c:

Scan_sample_20w-30_-_rep_c.png

Sample # 20w-30 similar matches for rep c:

Scan_sample_20w-30_-_rep_c_closest-matches.png

Comparison of all 3 reps for sample # 20w-30:

Scan_sample_20w-30_-_comparing_all_reps.png

6) Scanning unknown sample # 80w-30

Next we scan sample # 80w-30 and carry out three repetitions of the scan.

IMG_4143_-_80w.JPG

Scanning of sample # 80w-30, rep a, capture page:

Scan_sample_80w-30_-_rep_a_capture_page.png

Scanning of sample # 80w-30, rep a, annotation:

Scan_sample_80w-30_-_rep_a.png

Sample # 80w-30 similar matches for rep a:

Scan_sample_80w-30_-_rep_a_closest-matches.png

Scanning of sample # 80w-30, rep b:

Scan_sample_80w-30_-_rep_b.png

Sample # 80w-30 similar matches for rep b:

Scan_sample_80w-30_-_rep_b_closest-matches.png

Scanning of sample # 80w-30, rep c:

Scan_sample_80w-30_-_rep_c.png

Sample # 80w-30 similar matches for rep c:

Scan_sample_80w-30_-_rep_c_closest-matches.png

Comparison of all 3 reps for sample # 80w-30:

Scan_sample_80w-30_-_comparing_all_reps.png

Note: I thought I had forgotten to compare all three reps for this sample, but it was not possible to go back and select them after I had done many other readings; only recently captured spectra apprear in the compare window and the search function does not return results outside the listed recently selected spectra

7) Scanning the Diesel sample

Next we scan the Diesel sample and carry out three repetitions of the scan.

IMG_4145_-_Diesel.JPG

Scanning of the Diesel sample, rep a, capture page:

Scan_sample_Diesel_-_rep_a_capture_page.png

Scanning of the Diesel sample, rep a, annotation:

Scan_sample_Diesel_-_rep_a.png

Diesel sample similar matches for rep a:

Scan_sample_Diesel_-_rep_a_closest-matches.png

Scanning of the Diesel sample, rep b:

Scan_sample_Diesel_-_rep_b.png

Diesel sample similar matches for rep b:

Scan_sample_Diesel_-_rep_b_closest-matches.png

Scanning of the Diesel sample, rep c:

Scan_sample_Diesel_-_rep_c.png

Diesel sample similar matches for rep c:

Scan_sample_Diesel_-_rep_c_closest-matches.png

Comparison of all 3 reps for the Diesel sample:

Scan_sample_Diesel_-_comparing_all_reps.png

7) Scanning the Crude sample

Next we scan the Crude sample and carry out three repetitions of the scan.

IMG_4148_-_Crude.JPG

Scanning of the Crude sample, rep a, capture page:

Scan_sample_Crude_-_rep_a_capture_page.png

Scanning of the Crude sample, rep a, annotation:

Scan_sample_Crude_-_rep_a.png

Crude sample similar matches for rep a:

Scan_sample_Crude_-_rep_a_closest-matches.png

Scanning of the Crude sample, rep b:

Scan_sample_Crude_-_rep_b.png

Crude sample similar matches for rep b:

Scan_sample_Crude_-_rep_b_closest-matches.png

Scanning of the Crude sample, rep c:

Scan_sample_Crude_-_rep_c.png

Crude sample similar matches for rep c:

Scan_sample_Crude_-_rep_c_closest-matches.png

Comparison of all 3 reps for the Crude sample:

Scan_sample_Crude_-_comparing_all_reps.png

My favourite functions in Spectral worksbench in this exercise was the "Find similar" button. I will in the future go back and write a bit more about some of the interesting 'similar' spetra that I found. It would have been useful to have a "how to dispose of your samples" and "how to clean your cuvettes" guides. I first used acetone but it damaged my cuvettes (I lost two in the experiment). I then used dishsoap but to no effect. I then used window cleaner and that seemed to do the trick!

Related research notes:

Oil testing kit Beta programme - Package content

Oil testing kit Beta programme - Assembly: cuvette frame

Oil testing kit Beta programme - Assembly: spectrometer

Oil testing kit Beta programme - Calibration

Oil testing kit Beta programme - Technical adjustments (hack!)

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Oil Sheen Testing

by Matej | about 9 years ago | 5 | 3

What I want to do

I want to find out the most effective and DIY friendly way how to collect and concentrate oil sheens from a water surface. I will be trying to test several new but also already existing accessible techniques that are non-toxic or otherwise harmful for the environment or living organisms.

My attempts and results

Since I will be testing several different techniques of oil water separation (OS), I will post attempts & results from each approach into a separate research note. All the notes will be linked under the OST (Oil Sheen Testing) tag and OS tag. In case there will be a new addition to a particular research note, I will post a direct link into the comments section.

Different Techniques of OS:

Magnetic Fluid Oil Separation Centrifugal Oil Water Separator Separation of Water and Oil by Freezing the Water Membrane for Separating Oil and Water Funnel Fuel Filter Hydrophobic Fabric: FabricGore-Tex, Teflon Fabric, Natural Hydrophobic Coating for Textile Hydrophobic Membrane Bio Membranes (?) Compressed Air OS ... and maybe more to come.

General Evaluation Technique:
  1. take triplicate spectra of oil
  2. take triplicate spectra of oil mixed with water (try starting with 1:20 oil:water dilution)
  3. run a separation technique
  4. take triplicate spectra of separated products (what we think is predominantly oil, and what we think is predominantly water)
  5. if spectra of initial oil is the same as the spectra of the separated oil (post mixing with water and separating), then repeat procedure with each oil type.
Oils Products That Will Be Tested (so far):

20W50 05W30 80W90 North Dakota crude (Crude) Dielectric Fluid from Con-Eddison (ConEd) Auto Diesel (AutoD)

Questions and next steps

Main question is: What is the most effective, safe, clean, cheap, environmentally and user friendly way to separate oil from water? And: What is the best way to collect the water?

Next steps:

I already started testing the "OS by Freezing Water". Please look for the a new separate research note dedicated to this technique. I will post it tomorrow. - As I mentioned my goal is to test all of these techniques.

Why I'm interested

I am interested to test figure out a way how to prepare best specs for the OTK and to test the ability of different different DIY techniques to separate oil from water.

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spectrometer oil-spill oil crude


Oil testing kit Beta programme - Calibration notes

by cindy_excites | about 9 years ago | 6 | 2

Oil testing kit Beta programme - Calibration notes

Contributors: @TedF and @cindy_excites

Date: 31/Oct/2015

Here we document our experience using Spectral workbench to calibrate the Public Lab Spectrometer 3.0, which we assembled using the instructions provided there. We also put forth a few humble suggestions, including a "for dummies" outline of our steps.

1) Aligning the 'spectrum' When first trying to capture spectra, we noticed the line was not straight. We opened the spectrometer's black cardboard frame to tweak the DVD fragment and improved the angle:

Crooked_spectra.png

Still not satisfied with the angle of the refracted line, we reopened the spectrometer to adjust the angle of the DVD fragment:

Aligned_spectra.png

This is what it looks like on the inside:

IMG_4125.JPG

(I admit that since I did not understand why the DVD fragment didn't have to cover the whole of the 'mid hole' of the 'diffraction grating angle' I covered the whole thing. Maybe it will come back and nip us in the butt! However, I did this because as you will read below, I had qualms about the DVD fragment's quality due to unsatisfactory separation. If the quality of the DVD fragment turns out to be problematic, I'll try @ethanbass's recommendation with MrBumper's method).

Success! We used the lamp from a phone - shining it directly into the slit - to check this. At first I thought this misalignment was due to the DVD not having been peeled/separated properly:

IMG_4122.JPG

Does it matter if it still refracts the light? What is good enough for a DVD fragment? Here is our piece of DVD:

IMG_4120.JPG

2) Working with Spectral workbench…

Spectral_workbench_calibration_success.png

a) What is that little red lightbulb telling me??

Spectral_workbench_-_red_lightbulb_crp.jpg

When trying to capture the light of a CFL lightbulb, we noticed that that the 'Detected fluorescent light' bulb symbol turned red. We searched the website for guidance on this but couldn't immediately find anything…). We assumed that it meant that fluorescent light had been detected… although it did not always turn red when capturing our diffused light… Does it warn for overexposure instead…?

The youtube video on calibration on the 'Spectral workbench usage' page is very easy to follow even though it features the previous version of Spectral workbench. However, I'm wondering if for the absolute beginner, it might be useful to have visual guide: a screenshot of the new Spectral workbench interface with little arrows pointing to what the different buttons do.

b) Figuring out how/when to capture spectra…

It took us a little while to get acquainted with the site; we did not really know what exact steps to follow and without background knowledge or points of reference. However, in the end we made it and decided to create a "Calibration for dummies" version of our steps. Might be useful for the absolute beginner :O

i) We arrive at Spectral workbench using the Firefox browser (seems to work better than Chrome). We share our camera labelled "USB 2.0 Camera" as opposed to the integrated camera:

Spectral_workbench_-_camera_sharing_menu.png

Spectral_workbench_-_camera_sharing.png

ii) We shine light from a CFL bulb at the spectrometer's slit. We see the live image on the top left and the video row on the centre screen. We click "Begin capturing"

iii) With a steady 'flow' of light into the spectrometer, we get continuous rows of colour bands on the central spectral field. When happy with the output of this, we click the blue "Save" button on the left:

Spectral_workbench_-_successful_spectral_capture_using_plastic_bag.png

We receive message "Spectrum was successfully created". Yey!

NOTE: Our original capture returned an error message "You must be logged in". We repeated the procedure and we received an error message warning that our spectrum is overexposed. We click the link to "how to fix this" [ http://publiclab.org/wiki/spectral-workbench-usage#Overexposure ]. We opt for using a diffuser - a plastic bag (a clear one, not a milky one):

IMG_4127.JPG

iv) We then proceed to calibrate by clicking the blue "Calibrate" button on the bottom left.

c) Calibration procedure

Step 1: A pop-up appears instructing us to select the middle blue band of our spectrum; we click "Begin":

Calibration_procedure_1of5.png

Step 2: We move the cursor and place it on the peak of the curve for the middle blue band as instructed:

Calibration_procedure_2of5.png

Step 3: Once selected, a next pop-up appears instructing us to select the green band. We click "Finish":

Calibration_procedure_3of5.png

Step 4: We move the cursor and place it on the peak of the curve for the green band as instructed.

NOTE: The second pop-up confused us at first: we were not ready to "finish" as we had not selected our green band. This prompted us to click outside the box only to realise that we'd lost the calibration. In terms of usability, it might be best to have the blue button say "Next" and then a third pop-up saying "Finish", which then leads to the appearance of the "Great! Calibrated" message at the top of the page:

Calibration_procedure_4of5.png

Calibration_procedure_5of5_great_calibrated.png

Step 5: optional Out of curiosity we clicked on the "Find similar" button - fifth to the right of the "Calibrate" button and got this:

Calibration_procedure_-_closest_match.png

We also clicked on "Compare" - fourth to the right of the "Calibrate" button:

Calibration_procedure_-_compare.png

Calibration_procedure_-_compare_output.png

d) Next steps

Now (we suppose) we can select our best calibration capture when testing spectra from our cuvette:

Calibration_-_next_steps_1.png

Calibration_-_next_steps_2.png

Calibration_-_next_steps_3.png

Other research notes in this series:

Oil testing kit Beta programme - Package content

Oil testing kit Beta programme - Assembly: cuvette frame

Oil testing kit Beta programme - Assembly: spectrometer

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spectrometer calibration fluorescence spectrometer-calibration