Interesting prototype on MobilePhone Raman Spectroscopy

Finally found some decent research on (DIY) Raman Spectroscopy here:
https://aip.scitation.org/doi/10.1063/5.0046281
found the full article here.

I am interested to try this out myself. We had this idea for many years to test different fermented beverages with such a method. Who wants to join looking deeper into this?

greets,
m

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Ni! Not a lot of time in my hands right now, but I’d be interested in following up.

I know @janluctavares would like to follow up.

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@few what do you think about this?

Interested!

I like the article, but it’s not all that practical for most of the cases that people typically use Raman spectroscopy in.

Yes, with the cell phone camera it’s possible to record Raman spectra of Rhodamine 6G (a very bright dye) or resonance Raman spectra (which means extremely bright signals) of specific compounds. Raman spectra of water/ethanol will have very low background fluorescence. For transparent (non-scattering) samples, a 90 degree sampling configuration avoids the need for using laser rejection filters (like Chroma, Omega, Iridian, SEMROCK, or Alluxa dichroics or long-pass filters, 1" = 700$).

The linearity for the cell phone system is better than I would have expected (Figure 10), but you can see that the signal-to-noise is marginal, even for the extremely strong water bands (Figure 12).

These ones seem more interesting:
https://pubs.acs.org/doi/pdf/10.1021/acs.jchemed.0c01028

https://e-publishing.cern.ch/index.php/CIJ/article/download/799/577/3552

https://journals.sagepub.com/doi/10.1177/0003702816665127

https://erossel.wordpress.com/ (Esben Rossel also built up a great linear CCD detector)

https://thepulsar.be/

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So lets FIND a case for which this more simple and low-cost setup IS practical!
any suggestion?

i wanted to measure alcohol content in fermented beverages once. not sure if the resolving power in the low content is enough. 0 - 10%… and loads of other stuffs in there.

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Very interesting project. I am very busy with another open hardware project at his moment, but I can provide some tools, if someone wants to take this further, if you contemplate a **collaborative venture **. They were created in the context of open source scientific instruments made for practicing open science.

You can start with this template that helps a group of people collaborate on design (copy and remix as you please). The methodology is designed to leverage stigmergy and collective intelligence, which are not just empty words or buzzwords…

You can get inspired by our plant protein extruder, designed open source with DIY in mind. In order to have an impact, we create an open venture around this solution and build a dissemination network (the equivalent of marketing and sales, but we’re not selling a product, so we bypass market / transactional dynamics). To insure future stability we design ecosystem services (repositories, communications and peer learning tools, etc.) around this hardware solution. A model similar to Precious Plastic if you will.

The Raman spectrometer and other similar devices are very suitable for such open and collaborative ventures. The problem today is that everyone treats these instruments like a small / personal project and they get designed in an uncoordinated fashion. The true power of open science and open innovation is unleashed when all these instruments share standards, become interoperable and share features that ties them to the open culture and to underlying economic model. There’s no coherence because there is no true economic engine behind these projects. When we speak about a collaborative venture we go beyond the project. We project further into the future and connect with other things. We include economic considerations into the process. We see a bigger picture.

So you can collaborate on a project and make yet another stand alone device, or you can collaborate on a venture and add more coherence to the field, develop open science, open innovation and a commons-based peer-to-peer economy.

More about Collaborative Entrepreneurship.

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The cell phone Raman system could probably do from 1% or 2 % to 10% ABV. But there are other very simple and inexpensive ABV measurement solutions like a refractometer or hygrometer (5-20$).

I am happy to collaborate on this project.

The below is the best approach for the alcohol measurement.

But for DIY approach, one can try the below method

We have many Raman spectrometers in our lab and some expertise in building Raman systems from the scratch. So I am happy to collaborate on this project.

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As i understand, the ABV measurements are done BEFORE the fermentation, means they measure the sugar content, and the rest is calcucalted assuming full conversion of the sugar into ethanol.

I’ll start now to prepare for a first prototype. will base the design on GaudiLabs recent spectrometer.
https://www.gaudi.ch/GaudiLabs/?page_id=995

I have only access to a 20mW laser pointer atm, but good enough for a start.
But don’t know where to source the lenses, which are described in the paper above. It just says, amazon… any idea?

So i started prototyping a version of a raman spectrometer in the last couple of days. learning about different laser diodes, 3d modeliing prototyping optical setups compatible to the 3D Printable Fiber Spectrometer Kit from GaudiLabs @gaudi and learning a lot more on lenses… (which is where i am stuck at the moment). Checking this distributor from China.

Modeling those modular parts with openScad which can then be later integrated in some 3d printable setup.

At the moment i am using a module from a green laserpointer, 532nm, but i also learned that they are not suitable, as they also have the IR peak. So i am looking into a good 520nm laser diode to use, and a suitable cirtcuit for the constant current source.

Let’s organize a call for all people interested to share some ideas on how to proceed with such a low-cost / DIY raman spectrometer. Ping here to show your interest, i’ll set up a poll for choosing a date and time.

I would be interested to be in the call. I’m in EDT and available most time except for very early mornings (before 9:30 AM)
Maybe the green laser pointer is still fine if you can filter the IR out using a filter or with the sensor. It seems to be the cheapest alternative.