Spectroscopy and material sensing
Material sensing is about making the optical fingerprint visible by the means of optical spectroscopy.
So using spectroscopy means you can identify, qualify and quantify the material composition of either a liquid or a solid material.
First you need a light source. With that light source, you shine onto your sample, onto your object, and then a portion of the light is absorbed by the substance and another portion is back reflected.
The back reflected part you detect with your sensor. And with that back reflected part, you can extract the sample composition and information about the sample material.
An optical fingerprint is very comparable to my fingerprint. So I have a very unique fingerprint, you have a fingerprint and they are different.
And each material has its own optical fingerprint, which we are able to detect utilizing optical spectroscopy. So plastics, water, sugar and any ingredient of any substance is unique and can be measured by optical spectroscopy.
NIR spectroscopy is a very versatile technique. For example, you can measure the moisture content in grains or textiles or the composition of shirts or the dry matter content of animal feed. And the underlying origin is, that these materials are composed of a molecular structure. That means that certain atoms are interlinked by a chemical bond and this chemical bond can be nicely measured with NIR spectroscopy.
The possibilities are rather broad. For example, you can measure what a shirt is composed of, you can measure food, you can measure liquids and you can measure solids. Because there is a molecular structure behind all these things.
Even though NIR spectroscopy is a very powerful technique, there are certain limitations.
For example, too low concentration applications are hard to measure. This means gases or water vapor are very hard to measure, but also when it comes to bacteria and virus measurements.
First of all, you need proper technology. Our SenoCorder devices are very good to solve this problem.
Secondly, you need the right samples, the right amount of samples, the right quantity of samples and the right presentation of the samples in front of the technology. Then each sample needs to be tagged with the right reference value.
And third, you need to apply the correct chemometric algorithms, which are statistical methods, in order to interlink the analyte you want to measure with the spectra you get out of your technology.
You need to measure enough samples in a certain environmental conditions, and you need to analyze the spectral data by applying chemometric algorithms in order to extract the information you want and to refer it to the actual reference value you are looking at.
For example, false light coming from the sun can have impact on your results. But also, the temperature if is varying whilst measuring. You need to apply all these environmental conditions to the chemometrics itself – you can account for many effects and you can correct them. For example, you can measure your substances at different temperatures leading to a more robust model, robust in the sense that it’s not so sensitive to different temperatures.
A chemometric model is important in order to enable NIR spectroscopy. So chemometrics is a mathematical, statistical approach to interlink the spectroscopic data you get out of your hardware with the analyte of your samples.
So this means you need a rather broad set of samples, a large amount of samples, because it’s a statistical approach. And then once you have set up your chemometric model, you can validate and apply the model.
You use your technology, you take a measure of your shirt and then you get the answer of whether this is cotton or polyester.
In NIR spectroscopy, you need various components. First, you need a detector material: silicon or indium gallium arsenide.
Second, you need a dispersive element, for example a grating or a prism, and another optical component as an entrance slit. Altogether, you end up with a rather bulky system.
We at Senorics, we merged all these components together into one single chip. Like this one. And so the magic is combined in this single chip and the basis is organic electronics. So as known from organic light emitting diodes and organic solar cells, we used a very similar technique to realize NIR spectroscopic sensors. And another cool feature is that these detectors are not broadband in comparison to silicon or indium gallium arsenide. But they are spectroscopically tailored to the right application.
So this means we have narrowband absorption bands, which we can adopt to the right application.
Our Senorics sensor works without a classical dispersive element. What we are utilizing is a filter technology, and we combine that with an organic photodiode technology.
So each pixel is then sensitive to a certain spectral region, which can be narrowband, we can tailor made this and we can repeat that. In our case we have 16 pixels on one chip and can cover the entire spectral region of the NIR.
16 pixels are indeed enough in the NIR in order to solve all spectroscopic and chemometric applications.
Typically you have 512 or 128 pixels, but this is for conventional technology. When you have in mind that a typical spectra in the NIR is rather broadband, features are smeared out and there are no sharp features in the spectra, you don’t need this high resolution to solve your problem. So 16 channels with our resolution is fairly enough in order to solve all the chemometrics applications we have in mind.
Our sensors are very small, they are very robust, they are very cost effective because we are relying on organic electronics.
So we have basic technology, basic facilities to produce them, they are fully scalable and so we can bring them into mass market applications.
We have no moving elements, so you don’t need any translation time to move any component. And we have PIN photo diodes, they are extremely quick. The retort can in principle be done in the nanosecond range. Of course, electronics are not capable of taking the same speed as our sensor, but we can measure the entire spectrum in the micro or millisecond range.
The lifetime of our sensors is basically not limited. Of course you will have in mind that, for example organic light emitting diodes have problems with lifetime, but this is a problem of the past and is dedicated to the spectral regions they are working in. For example, the blue spectral region has rather high energy photons and these high energy photons are harmful, or can be harmful to the organic materials.
We at Senoricsare dealing with NIR spectroscopy. So these are rather low energy photons and they are not harmful to the organic materials in any way. So therefore we don’t have any problems with lifetime with our sensors.
Download latest version of software SenoSoft using this link.
Navigate to section “Download Software” and click on download link.
Save zip-file in local folder, unzip into another local folder (using built-in Windows capabilities). Make sure you have full access rights to this folder, otherwise SenoSoft will not work properly. This will be your start up folder for SenoSoft, there is no installer. Bookmark the file start.bat located at Senosoft local folder / bin. This will be your starting point for using / executing SenoSoft.
1. Connect the battery pack with the SenoCorder Solid or SenoCorder Liquid by using the USB cable.
2. Battery pack will automatically turn on when connected to Senocorder Solid, blue indication lights will indicate battery charge status. If needed, manually turn on with single click on battery pack power button. Battery pack will turn off automatically after ~1 min non-use. Can be turned off manually by double click on battery pack power button.
3. Data connection to PC only via Bluetooth. If PC has no built-in Bluetooth connectivity use Bluetooth dongle included in this package. Follow installation instructions once the dongle is connected to your PC.
Make sure SenoSoft is either installed in a local folder with full access rights or that you have admin rights and started SenoSoft with “Start as Administrator”.
Make sure that the battery pack is (i) connected to the Senocorder Solid device, (ii) is turned on and (iii) is not connected to a USB port for charging at the same time when operating the device.
Recalibrate Senocorder Solid by using the re-calibrate button and follow the shown instructions.
Hardware and Devices
Use standard micro USB charging cable and charger (as typically used for your mobile phone) and fully recharge battery pack when only one indicator light remains lit on.