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OpenRAMAN – Low-cost, high-performance, open-source Raman spectrometer (open-raman.org)
149 points by philipkglass on May 5, 2020 | hide | past | favorite | 30 comments

In case you're curious, the license on the downloadable drawings for the "Starter Edition" is CC Attribution-NonCommercial-NoDerivatives 4.0

I mention this because it seems counter to what calling something "open source" means to most people. On the main page of the project, they say "It is strictly reserved for non-commercial applications" which... IANAL but I think the license limits commercial use of the design, but not of the device created with the design? Also NoDerivatives runs pretty counter the open source ethos IMO.

Thanks for the comment.

This project is not open. A non commercial license is in direct conflict with what is the commonly accepted definition of "open" (source or hardware) [1].

Normally when hardware projects claim to be "open source", I give them a pass as they sometimes have the code or other firmware under a GPL-compatible license even when they have the hardware files under a proprietary or non-commercial license. This content is not providing any source or other files under an open/free/libre license.

This project is "open washing" and should not be considered an "open source" project.

[1] https://en.wikipedia.org/wiki/Open-source_license

> " ... Licenses which only permit non-commercial redistribution or modification of the source code for personal use only are generally not considered as open-source licenses. ... "

Afaik academic research isn’t considered commercial. I work in a lab that has a RAMAN spectrometer.

the problem with noncommercial licenses is that there is no commonly accepted definition of commercial. a simple definition of "you receive money for your work" excludes the vast majority of potential users. you get grant money? that's commercial. you post videos on YouTube? that's commercial. and even if it isn't, you may spend a significant amount of money defending a lawsuit. for this reason, any competent lawyer will tell you to stay far away from NC licensed material.

So the kit costs €2300 for all the parts.

Looking through the BOM, I feel there's a good bit of fat to be trimmed actually. They splash €85 on a linear regulated power supply (you can get something similar giving clean power for $20 in bulk), and the camera setup (sensor, lens, related hardware) costs more than €600 in total. While there's a good reason they picked the lens they did [0] I feel the sensor (might) be replaceable by a new Raspberry Pi setup (also C-mount) - that'd save $400!

Then there's a lot of money (couple hundred) in fancy plastic/aluminum parts. Manufacturing in higher quantities could save quite a lot there.

There's some stuff that is much trickier to push down in price much: laser stuff/dichroic mirrors, filters, etc are tough.

Still, though, I feel that this has potential to eventually come down a good bit in price, and I really look forward to seeing that eventually happen!

[0] http://www.thepulsar.be/article/raman-imaging-lens-upgrade/

For those looking to build their own, this still costs 2500€. For a lower quality but cheaper option, check out Ben Krasnow's (Applied Science) video: https://www.youtube.com/watch?v=tRrOdKW06sk

Caveat: this is much lower quality, but for a "home" kit, this is probably better. The OpenRAMAN edition is much higher quality and aimed lowering the bar to entry and making lab setups cheaper (Raman Spectroscopy can actually be useful in a lot of settings).

I saw that the person who developed this device is looking for academic partners to take it further: https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

It seems very well developed. The open source RamanPI [1] got some traction here a while ago. This looks like it may be more costly than RamanPI but it also is more thoroughly developed.

[1] https://news.ycombinator.com/item?id=8395506

The original RamanPI project looked interesting but doesn't seem to have gone anywhere after several years, unless I'm mistaken. If there's any actual data from it, I couldn't find it.

On the other hand, Luc's results are drop-dead awesome: http://www.thepulsar.be/article/some-diy-raman-spectra/

I love the raise of open source / hobbyist experimental science. I have two used qPCR machines at home (which I bought for $450), and I have established relationships with Sigma-Aldrich and other consumables providers, so I now can e.g. run my own qPCR tests for SARS-CoV-2 RNA presence, as well as many other experiments.

For those out there interested in DIY molecular diagnostics, in addition to qPCR, also check out this new technique:

"SHERLOCK-based one-step test provides rapid and sensitive COVID-19 detection: New CRISPR-based research tool delivers results in an hour in a one-step reaction, advancing the technology closer to a point-of-care or at-home testing tool." - https://mcgovern.mit.edu/2020/05/05/sherlock-based-one-step-...

"STOPCovid is an effort to develop point-of-care and at-home tests for COVID-19. Developed by scientists at MIT, the McGovern Institute, and the Broad Institute, our test relies on a number of enzyme innovations to enable rapid detection in less than an hour without any complex instrumentation. We are committed to providing simple and easy-to-use tests that can be used in any setting so that society can reopen. On our website, we will provide updates as well as live clinical data from within our collaborator network. We are committed to working with partners to validate and distribute test kits. Please reach out to us (STOPcovid@mit.edu) if you are interested in working with us!" https://www.stopcovid.science

What’s your approach for getting covid19 template dna for the positive control reaction?

Just bought the positive control RNA template, it is included in most kits.

That sounds really interesting, have you written up any of your experiments anywhere?

Not yet. I play to make a full report when I will receive a final component (low ROX master mix).

There are some quite inexpensive 530nm OPSL lasers available now, I wonder if the improved frequency stability would reduce the spectral broadening in these results?

It'd be really fun to race Nmr/MassSpec/Ir/Raman teams to see who can make a cheaper home gamer analysis tool.

My money would be on mass spec, although it requires high voltage and vacuum. Back in my old university days Zbigniew Gasnaya made a home gamer mass spec that worked fine for what looked to be about 300$ in today's parts

3 high DC voltage plates, a harbor freight vacuum, an amp...

Ben Krasnow took some steps in that direction: https://www.youtube.com/watch?v=nIKhUizkXxA

As with his Raman setup, there were some good questions raised in the comments about whether he really saw the effect in question or just got lucky with plausible-appearing artifacts. It's hard to assess validity from the presented results alone, which is unfortunately common in Ben's videos. In the Raman video, he didn't test anything but a single styrofoam cup, and in the mass-spec video he didn't do the obvious baseline run with a clean filament.

Ben's channel is one of those rare ones where the comments are worth reading. You can really see how easy it is for a scientist to inadvertently fool themselves and others. I often end up yelling at the screen, but it's still my favorite YouTube channel of all time.

I'm a huge fan of Ben's. In all honesty Zbignew was definitely more talented at munging together homebrew instruments. But who could compete with that old timey eastern bloc science curriculum ;).

I think Ben's misused over there at google. He should be designing the national high school science lab curriculum.

What are some uses for this? This is not my field so any types of experiments is nice that would help understand some general use cases. The last time I used one of these was for my physics "optics" lab. If I recall correctly, we used a grater of some sort which filtered out the light wavelengths which was displayed. It was so long ago, I can't recall the lab project.

I used one extensively to map residual stresses in sintered ceramics

Can this be used to identify molecules and act as some kind of Tricorder?

Yes, it can be used to identify molecules. Here is an example application:


It can be used to detect and quantify methanol in ethanol. This is interesting because ethanol is (relatively) safe to drink, while methanol is metabolized to poisonous compounds when ingested. Methanol and ethanol look the same and have nearly identical densities. The odor and taste of methanol are distinguishable from ethanol only at high concentrations. Raman spectroscopy is one way to distinguish a dangerously adulterated alcoholic beverage from a safe one.

You do need to put a sample of the substance to be tested in the machine, though. You can't point the machine at a container in front of you and get a reading. Also, Raman spectroscopy is suitable for distinguishing many but not all substances. The Tricorder's capabilities for universal remote analysis are superior if fictional.

Nah, we do this daily for ID of chemicals as part of a GMP release. We use a handheld Raman spectrophotometer--just point it at the stuff and it gives you the spectrum.

Here is a paper detailing its use in determining methanol content of ethanol spirits: https://pubs.rsc.org/en/content/articlelanding/2019/an/c8an0...

I thought you needed to keep the sample very dark and only illuminate it with a laser so you can see the changes in reflected wavelengths. How does a handled unit with light all around get around that?

Raman is very particular for the Stokes transition. When compared to other spec methods, it is much easier to cancel out background.

The odor and taste of methanol are distinguishable from ethanol only at high concentrations.

The methanol I've worked with has a strong wintergreen odor, impossible to mistake for ethanol. I'd always assumed that's just what methanol smells like. Is it actually an odorant?


How small can a Raman spectrometer, or its alternatives get?

The only consumer product I know that resembles this is the SCiO: https://www.consumerphysics.com/scio-for-consumers/

I've been involved in designing optical instrumentation. There's a challenge with miniaturizing optics, which is that light obeys an "optical invariant," which limits the area and solid angle subtending a light beam. In practice it means that as optics get smaller, it gets harder to maintain signal-to-noise and spectral resolution, which affect the ability to distinguish chemicals with similar spectra, chemicals at low concentration, and dirty samples.

Not everything is so constrained. Lasers can get smaller. Certainly electronics. As those things get more efficient, the batteries can get smaller.

Now, it all depends on what you're trying to measure. And there are cases where the chemicals themselves cooperate with you in some way. For this reason, single purpose instruments can often be quite small. An example is the finger cuff for blood oxygen.

If you search for mini- or micro-spectrometer, you'll find that these things are all over the place. Many of them demonstrate one interesting application with great fanfare, that is perpetually almost sensitive enough for practical use.

There's a little tear down of how the SCiO works, which might be of interest - https://learn.sparkfun.com/tutorials/scio-pocket-molecular-s...

It seems quite simple, in that it seems to use a light source and looks at the reflection using photodiodes with different lenses on top.

So as I understand it wouldn't perform as well as a spectrometer with diffraction grating and linear CCD, but would be interested to hear from someone knowledgeable about spectrometers about that.

But it does seem to use a simpler principle than a raman spectrometer, I believe this is the general term for the approach it uses - https://en.wikipedia.org/wiki/Near-infrared_spectroscopy

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