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TortugaGuardian Sea microplastic opensensor FTIR spectrometry

Hi @All im writing to tell you more about the Tortuga Guardian project - http://tortugaguardian.org, which started during the Laboratorio de Innovacion Ciudadana in Costa Rica in 2019 - #LabICCR https://www.innovacionciudadana.org/LABICCR/pt/ from of a proposal that I submitted.

Among the 10 projects selected in the prototyping stage, we were selected for a later stage, POST LabIC as they are calling it. There are 5 projects that have continued and will receive an incentive to start developing the proposal, we are in the initial phase with a team of 8 researchers and developers to initially install 5 Tortugas Guardians and leave them in operation until the end of this year, at first 5 countries where our team members are: Brazil, Costa Rica, Mexico, Uruguay and Australia.

We are in the development phase of the opensource microplastic sensor, using FTIR spectrometry and openCV image detection techniques;

Here is a list of articles about infrared spectrometry research for detection of microplastic particles in different sources: https://docs.google.com/document/d/1FkqGtkY3t9O804kUIUCr8erDGM8K6NpF12QcMC_bfD8/edit?usp=sharing

The first 3 articles are the most relevant in terms of innovation because they are about the FTIR spectrometer in a microchip, the others are related to how well the technology is used for the detection of polymers and their markers.

We have in total including material values ​​and taxes 10k Euros to start the project, supported until January 2021. It is not a big budget but it helps us to start development and open and citizen research, with the objective of publishing a article at the end of the homologation of the sensor that analyzes the concentration of microplastics in marine water in situ, in real time and completely open source with free licenses.

Im responsible for the technological coordination and spokesperson of the project, we are looking for partners to prospect for more Tortugas that join our network in the long term, certainly for that we need local articulation and citizen scientists in the nearby community. We are also concerned with making the incentive we receive income for research, development, purchase of materials, installation and training workshops throughout the year.

Our target audience is scientists and citizens who are in tune with the principles of open science and social technologies, in order to articulate the project as a device for public information on the marine ecosystem.

As the microplastic sensors are still under development to improve the quality of reading, we believe that the material costs at the beginning are a little higher than estimated, we are looking to save on technical infrastructure, such as monthly fees for hosting web servers and if possible get a partnership with other devices, mainly public ones such as universities and research institutes for the calibration of sensors by our team on a monthly basis.

I//happy to be able to share the project with you and whoever wants to show it, we are getting around the pandemic by thinking about training strategies and online support material, in addition to the dissemination of data and movement to authorities, scientists and environmental communication vehicles.

Im currently looking for news and updates on the possible commercial existence of any of the FTIR spectrometry microchips for the development of the embedded spectrometer, with sample titration through a system of 3D printed pumps in adapted cuvettes.

At first I did the research to find LED diodes in the wavelengths of the IR absorbing polymers. However, FTIR, even without the ATR technique, or RAMAN spectrometry can be useful in detecting these microplastic particles.

I disregarded the use of UV because it would be necessary reagents in the samples;

We started prototypes with 720, 860, 940nm IR diodes and photodiodes, but this is just the beginning of the MID IR spectrum and there may be plastic particles with types that react up to 3knm

Our website is still under construction but the video has subtitles> https://www.youtube.com/watch?v=ienOsKmb7cA


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Hi @gsan!
welcome to the GOSH Forum!
Seems like a very cool project :slight_smile:
It is not really my field, so I don’t think I can help much, but there are some folks here who might be interested as they work in similar fields…

Pinging some people here, (maybe you are already in contact with them…in which case, forgive me for being nosy :stuck_out_tongue: )
@maxliboiron, @andrew.david.thaler @hikinghack @jeff (I know you are leaving public lab, but maybe you could point @gsan to someone there who might be interested?)

Maybe @gbathree also intersting for you?


I am confused about the “FTIR spectrometry microchips”. FTIR generally relies on a broadband light source recorded with a pretty simple broadband detector. The signal is generated by a moving mirror inside a Michaelson interferometer to create a Fourier Transform of the spectrum.

I am running an masters project next year to build a simple FTIR, but I think it will be way too fragile for this application. Have you considered using a diffraction grating to split up the signals? You can calibrate this using the spectrum of mercury by putting light from a florescent lamp into the spectrometer. You will probably need a more fancy grating than what you can get from a CD-R because the plastic will absorb the IR. We have found that you can limit this by using the CD in transmission rather than reflection by removing the backing from the CD with duct tape.

Hey Julian,
quick naive question: would something like this https://www.edmundoptics.com/f/holographic-diffraction-grating-film/11661/ be the same (or worse/better) in quality as a CD? I understand the appeal of using CDs, since they are maybe a bit easier to find, but not for long? Anyway, these gratings from the link are fairly affordable and are more defined in their properties…

I think one of the benefits of a CD is suppliers in many countries. While you may not find Edmund selling in all areas of the world, you will find a CD in e-waste. But as you say, that may not be true for long!

I would say that this is going to be better than the CD. The spacing on the CD-R is actually pretty well defined, but the tracks are curved and segmented.

What I don’t know is what limits the wavelength range for these gratings. It is 400-700nm which is only the visible range, so no IR. If it was the line spacing I would expect the range to change for the two different line spacings available. It may be absorbtion (but my quick google says polyester goes well above 700nm), it could be something else that I don’t understand…

H @all!

@amchagas, @efeefe was telling me about you and suggested to post here :slight_smile:

The turtle prototype started with two types of detection for microplastic particles (half a millimeter or smaller):

1 for Infrared FT / FTIR
2 by openCV image recognition + microscopic lens (built with smartphone camera scraps)

I have a list of research on forms of open source spectrometry and open academic research on microchip prototypes with FTIR spectrometry (I haven’t found this yet commercially);

The absorbance range of the polymers ranges from 720 to 3000 ~ 4000nm (MID IR);
there are open source RAMAN spectrometry projects (http://www.open-raman.org/), but I believe we could customize the costs by targeting only the MID IR absorption spectrum range

We made a prototype in Costa Rica with IR transmittance Diode LED 720, 860, 940nm and detection on the ground with a microscope made in a RaspCam, for detection of microplastics by OpenCV in a drop of water on the lens, we trained a recognition algorithms; Along with other sensors such as pH, temperature, turbidity in a community fishes on the Pacific coast, in the community El Jobo - Guanacaste; we transmit all the reading parameters by p2p LoRa in an ESP32, feeding the system with solar panel in a float made on pieces made with the aid of preciousplastic (another topic of study that is the reinforcement of recycled plastic so as not to suffer degradation with UV radiation ;

research ref opensource microplastic sensor
















Hardware Repository


https://equipamento-medico.lojaintegrada.com.br/cubeta-quadrada-quartzo-espectrofotometro-analisador-clinico [Brazil quartz cuvette];

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