DIY Light Spectrometer - webcam & diffraction grating - Applied Science at its Best!
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- čas přidán 1. 11. 2016
- NOTE FROM FEBRUARY 2010:
Folks, regrettably, the model featured in this video used a Standard Definition (SD) 640x480 camera sensor, taken from a webcam, which is no longer made or sold.
To work properly with the software, the camera needs to offer manual exposure, and I have been unable to find any. These days they are all automatic which fights with the software to find a good spectrum.
So I have had to move up-market to a dedicated HD camera. It is not harvested from a webcam, but is a stand-alone board shipped from China. Consequently, the base model is now more than twice the price.
Still, compared to, for example, an Ocean Optics desktop instrument, it is 10% of the price. I don't know of a better option, but if you do, please feel free to post in the comments, or to contact me.
On the plus side, the i-Phos HD offers full HD resolution, a glass lens and metal lens mechanics. That translates to spectra with more detail more linearity, and more stable - yo uonly calibrate once after warm-up.
I will make a new video about the HD i-Phos very soon, but for now, you can watch the old one via the link below. The enw one is identical in consutruction and use - only the performance is a lot better.
C-L-I-C-K-! chriswesley.org/spectrometer.h...
See how I used this instrument to test a commercial grow light:
• Grow Light Spectrum Te...
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The prototype USB light spectrometer in this video was homemade, based on guidance from the excellent Theremino project. These guys also wrote the excellent software which you see being used here.
The device is pure applied science. The webcam sensor is mounted at an angle behind a diffraction grating. Light enters a slit in the enclosure at the front. The diffraction grating splits light into its spectrum and that spectrum is seen by the webcam which connects to a PC via USB. The software analyses the image and displays a coloured graph of the spectral components. There are some bells and whistles to allow for instrument calibration, absorption spectroscopy, and more.
This instrument makes an excellent classroom spectrometer, and is much less expensive than, for example, the Rspec of the Ocean Optics devices, but please note that - whilst it provides an adducate measurement of wavelength, it provides just an appropximate of relative intensity. There is no measurement of photon flux density.
You can use it to analyse the wavelengths of a light source and their relative intensities. Using it I discovered that my cheap "UV Bug Zapper" doesn't emit any UV and this explains why it never did zap any bugs!
I used it to test the wavelengths emitted by various LEDs when I built my indoor grow lights. You can see that video here:
• Power LED Spectrum Tes...
Please consider supporting me on Patreon:
www.patreon.com/user?u=2709836 - Věda a technologie
I used to have access to professional instruments, but I am on disability pension, so it's hard to find a job, but I have always been interested in DIY projects, since I was very young.. I used to have a lab at home, but now I just have a little apartment, so I have to make it compact and easy to store, as well!
I'm happy that CZcams suggested your videos!
Thanks Tore!
Nobody cares about your boring life story. Stop trying to make everything about you!
Thanks for preparing this video.
I appreciate the link to Theremino.
That was such a well done demonstration...thanks so much!
Thanks David, I'm glad you liked it.
I have been researching for days on spectrometers for the same reason you were; testing LEDs for building grow lights. Thank you very much for this video! I just downloaded all the Theremino docs and sw. Now the fun starts....
Hi Ted, and thanks for your comments. I'll be uploading a video all about the grow light build soon. You can subscribe if you want to be notified when it goes up.
This is amazing, and exactly one of the solutions I was looking for. Thank you.
Glad you liked - thanks for making time to tell me.
Near Slit , What is there ??? Diffraction grating or Mirror ?How to select wavelength for this caase? for example 400-700nm for analytical analysis of chemical solution or dye /Where you had connected DVD Diffraction grading? Have you connected the mirror? At the edge of the slit? Or you have connected in front of the camera-Lens?How to get absorbance -wavelength curve for a cuvette
Thanks a lot for Sharing it. Regards from Brazil
Thanks Vinivius, you're welcome.
Really wish I'd found this before I retired from teaching!
I still may have a go at building it.
Thank you for sharing this video
You are very welcome Ziad.
Very good thanks for sharing 😊
very glad found this video!
Hi Devy - good to know.
man thanks so much for this, i've been looking the spectrometry software so long for my nanodrop projects
Hey Prasetyo, no problem. I'm glad you found ti useful. The guys that wrote it are clever chaps.
thereminio is my new light play toy. 🖥 it has fantastic results, so this video will be a huge help in learning. 😎 thanks.
Thanks for the video. When you point it at the sun, why is there a dip between the blue/green and green orange at 13:49? Is it mis-calibrated and were you able to fix it?
Dan Wozniak - great question. I don't have a good answer for you though. I will try it again and see if I can find out.
Did you figure it out?
@@chriswesley594 Is the window open when you point the spectrometer or the light shines through the glass?
@@user-ox2wz2op3y The window is closed so the light is coming through the glass.
@@chriswesley594 Could you redo the experiment with an open window and check if the dip is still there?
I just found this vid, I know this is sort of ancient as in CZcams years :) but I was excited. One because I like to tear things apart, but also because I think you have helped me to solve a problem. I hope I am thinking right on this. If I were to refit my old cam, I could potentially make a spectroscope that I could also use to take a photo of the image? Is that possible. If I were to fit it with a grating, then I could snap a photo with it if I take my laptop outside? Thanks kindly.
Hi Rita, I'm not completely clear on what you['re asking. If you put a diffraction grating in front of a camera lens and offset the axis, you can capture an image of the diffraction pattern caused by the image. So if you put the grating in front of your laptop camera it'll do that, but it won't be a spectromgraph of the light source - you need to collimate it to get one of those., which is why my spectrometer has a long tube with a slit at one end. But you can find adaptors you ca make online which will do it or you. Later today I hope to release a new video showing my new spectrometer which is for sale - so if you're interested you might want to subscribe - just a thought.
If I have not answered your question, please feel free to ask it again in a different way.
Most diffraction based spectroscopes have to make UV a special case since the first and second order beams have overlap in that region.
In my case, I use a glass littrow prism. It resolved best in the UV-blue region.
Some types of glass, especially if thick absorb most UV-B and even a significant portion of UV-A.
Great apparatus Chris, congratulations. Can you tell me the specifications of your webcamera? I prepare a Raman specrtoscope
DIY for education and I collect ideas!
Sorry I have not seen your comment before today. It is a 640 x 480 USB webcam.
Near Slit , What is there ??? Diffraction grating or Mirror ?How to select wavelength for this caase? for example 400-700nm for analytical analysis of chemical solution or dye /Where you had connected DVD Diffraction grading? Have you connected the mirror? At the edge of the slit? Or you have connected in front of the camera-Lens?How to get absorbance -wavelength curve for a cuvette
Thank you for all the instructions. Which cheap camera would you suggest for the project nowadays? I am a graduate student from Brazil interested in mounting a spectrometer to use it with Theremino in the obtainment of emission spectra of blue, green and UV LEDs, and CFL bulbs for my photochemistry studies. As a student, I can not afford to buy the I-phos spectrometer right now. Thank you very much for the help.
Good luck with building your own Thiago. Since I offer these commercially I don't provide details about how the camera I use.
Awesome video Chris! Ii your camera is not sensitive to UV could it measure UV? Also, it seems the camera would have varying sensitivity across the spectrum so you would need to do a gain vs frequency calibration. Maybe this would not be difficult using a known light source like the sun?
Hi Dave. apparently, without filters, a typical webcam sensor is sensitive to a much wider range of frequencies then the human eye - including UV up to about 200nm.
Regarding sensitivity - yes, I also thought about this. The Theremino software shown software allows you to alter white balance and automatic gain control settings, but I'm not entirely clear on precisely what they do in this context. There is no calibration settings to allow you to adjust gain at specific frequencies/wavelengths in order to null out non-linearities in the sensor.
However, the spetra I get from Compact Flourescent lamps are almost exactly like those in the documentation, which are in turn, very close to those obtained from professional instruments.
I think most sensor these days use the same sensor technology/physics, which may, with standard drivers, manifest reasonably linear behaviour.
Ultimately, for me, this is a hobbyist machine, so I'm not sweating it, but if you take it further I'd be very interested in what you find.
Near Slit , What is there ??? Diffraction grating or Mirror ?How to select wavelength for this caase? for example 400-700nm for analytical analysis of chemical solution or dye /Where you had connected DVD Diffraction grading? Have you connected the mirror? At the edge of the slit? Or you have connected in front of the camera-Lens?How to get absorbance -wavelength curve for a cuvette
Do you think it's possible to measure the black lines in the spectroscopic image? That'd be huge. Obviously not with a simple webcam. I was thinking of starting an Arduino project on this.
Your thoughts?
Hello Coldmow. If you mean an absorption spectrum, then yes, it is possible. By removing the slit aperture and changing a setting on the program. I have done some experimenting on it and will make a video on it, so if you're interested in that, you might want to subscribe.so you're notified when it is uploaded.
Impressive! I guess one could also calibrate with a TV remote and sunlight, as these are well documented. IR LEDs are generally well speced. Even without removing IR filter, the webcams I have tested were all quite sensitive to IR remotes, which are 850-1050 nm, depending on the type of remote. I tried that software, now v 2.5. Very easy to use.
Hello Dee and thanks for writing. With a TV remote - I know they're all near-infrared, but I don't know if they're all the same wvelength. They'd need to be a known wavelength to be used for calibration. Regarding sunlight - I've been doing a lot of work on this recently with my new spectrometer. Sunlight has a very broad spread of frequencies and it varies by time of day, time of year, atmospheric conditions, and location - so again - it's not great for calibration. There are atmospheric absorbsion lines which can be used though - one for oxygen and two for water. These are stable and could be used for calibration, though the signals are weak and not always visiable.
Much easier though, is a compact flourescent lamp (CFL). Their spectra vary from make to make, but all of them have a few characteristic lines which are always present - at 546 and 438 nm, which make excllent calibration references.
By the way, I'm making a new video about my new spectrometer which will be on sale soon, so if that's of interest to you you might want to subscribe.
Subscribed. Many shops sell IR LEDS that are tightly speced. TV remote LED cheap to replace. It has been a lot of years since I did a spectrum for the Sun. I was not aware the lines are shifting during the day. I reckoned it was mainly/only the measured flux. Thanks for input.
I'v done a video testing power LEDs using the spectrometer - in the Spectrometer playlist. I found they are not specified accurately, and also that the seller almost certainly substituted some blue LEDs he'd got in stock for some he hadn't because - "who's going to know?"., Well, a bloke with a spectrometer is going to know.
With this instrument, you don't see the sunshine spectral absorption lines as black lines in the image of the spectrum, but as dips in the graph of intensity over wavelength.
These lines don't move - their absorption wavelength is always the same s they're made by the same atoms and the same physics - what I meant in my earlier email, responding to your suggestion that I use daylight to calibrate the instrument, was that a daylight spectrum is a fat hairy blob, and not a line - but you COULD use the absorption lines.
Actually, these absorption lines DO move - due to the Doppler effect. Which is one of the way astronomers infer relative speeds between astronomical bodies. But that's not a problem between sun and Earth.
Chris: You surely know your stuff. Do you think the issue with the sunlight absorption lines is a resolution issue relating to the geometry of this rig? I didn't do the math yet, but I suspect intuitively that 1000 lines/mm grating and 1000+ pixel sensor are able to resolve sunlight very well. If grating issue, a lifetime supply of 13500 lines/mm grating rolls can be had on Amazon for very little money. I suspect that would spread a full spectrum across an area larger than the sensor, but you would get excellent resolution where you want it.
May I ask how you came to the conclusion that such exact spectral determination of grow lights for plants was needed?
Diverging far from your plant project, I have never heard of anyone claiming for or against this, but Sun might give a very weak Doppler shift from Earth that is measurable during a year due to Earth's elliptical orbit. There is cyclic movement towards and away from the Sun. I believe the Moon can be referenced because it is more circular orbit IIRC, but not sure how I would implement that.
Dee, I think you mean 1350 lines per mm - not 13,500. I'm familiar with the 1,350 line material. Instrument resolution and optics quality will certainly be limiting resolution. Spreading a spectrum big isn't the answer on its own. It inevitably means spreading it feint and blurry too. To get the best of every world you need to spend a lot of money on very high quality optics and very sensitive low-noise sensors. For my needs and my pocket - this instrument is all I need.
I didn't and haven't concluded that exact spectral determination is necessary.There i a lot of debate about exactly what is required and my conclusion from reading what was available is that no-one really knows. We know approximately and there are some safe assumptions we can make, but it's a developing science which has only really become relevant in the last few decades when credible indoor growing light sources have become available. I just thought - they could be selling me any old stuff and I'd never know - unless I bought red and they sent me blue, and I was curious about making an instrument that could tell me what' really going on.
Doppler shift due to the Earth's elliptical orbit is going to be un-detectable by any instrument I could ever imagine building so I'll leave that to you to worry about!. Make a video of what you come up with!
Nice video, but why do you remove the infrared filter? Do all the webcams have one of them? And can I replace the diffraction grating with a CD or a DVD?
I want to make your spectrometer for a school project. Thanks :)
Hi Lucas. I remove the Infrared filter so the camera can seem infra red light, which is of interest to many people who use spectrometers, but not generally to people who buy webcams. Yes, all webcams have them, as far as I know. If you use the camera normally when the infrared filter has been removed images have an odd appearance - eyes are jet black, hair has a bright glow, colours are all off, etc.
Check out the Theremino project for more on the build process. There can be a lot of fiddling to get it right, but if you're handy, it's not too difficult, and it would make an excellent school project - have fun!
Chris Wesley Thank you very much! You have a new sub :)
Hello Chris. Beautiful design, definitely a "KISS" design. Where did you buy the diffraction grating?
Hi Lee. I got the gratings on EBay.
Hi, great video thanks! I would like to test the light passing / nm value of a IR filter. Where would be the best place to put the filter, in front of the slit or the grate? Thanks again
Hi Jay, to test the IR filter, you'd need an IR source, and then look at the spectrum from it - with then without the filter in place. Put the filter between the light source and the spectrometer's slit.
Chris Wesley Thanks so much for taking the time to reply, answer was spot on! Much appreciated! 😀
No problem Jay - you're very welcome.
nice work :) but how can i export that data from the software and use it in analysis as .dat for example ?
It's a great question Khawla Ata. Currently, the only way to export the data is as a JPG image. You can choose to export the image the webcam is seeing, or the graph or a composite image of both. There is no digital/text dump available. The softweare is open source, so I guess you could implement it, but if that's not your think, then - at least for now - the answer is "you can't".
i have no time for implementation now :( and this project is exactly what i'm looking for , except that the software can't create an exportable file ,, Thanks for your reply at all =D
Hi Chris really great tutorial. Unfortunately, the used webcam is no longer available. Can you recommend a product which is available in 2024? All that typical cheap stuff has crazy features that might interfere with the intended use. Alternatively id be happy if you could detail the user requirements for a webcam to be used in such a spectrometer. Thanks a lot and have a good day!
Nicely explained video...with great clarity on topic
Can you please send the link of software that you have used
The software is part of the Theremino project. You can search online for it.
Thanks for the video. I couldn't afford to buy your spectro set, but I really want to build one, and I don't find the Trust WB-6250X webcam give in the thermino assembly pdf. could you please help me what camera should be good for this reason, and also I am on a thight budget. Thank you
Jakab, any webcam will do as long as you adjust the optical path to keep good focus. Good luck! PS: I know all about being on a tight budget from personal experience. If it helps you, I can provide a spectrometer for you at £35 plus P&P at cost.
You know, I am a craftsman type person. I will love every moment of the construction. Thank you thou for your kind offer and words. Bests Jakab
OK Jakab - have fun wth it.
Hi, thanks for the great video. I have a few questions that I hope you can answer.
1) Where can I download the software for the spectrum?
2) How do I hook up the webcam to the PC? To me, it was not clear from the video on what cable or connection to use.
3) In a previous comment, you mentioned a smaller version that was compatible wit smart phones. Do you have instructions for that constructions?
Thanks
1) Google Theremino or see the link in my description.
2) Plug it in to the USB port
3) No
Hi!
Can be diffraction grating placed directly to the camera sensor without any lenses?
The camera sensor uses a lens to form an image at the sensor plane.
"I think that's wonderful, there's nothing to see here" XD
Very informative. I am trying something similar with my scope and a Bahtinov mask and astronomy camera for stars and other celestial objects.
Hiya Baz and thanks for writing. I wondered about using the i-Pohs for astonomy but I don't have the time to give it. I like your Jupiter video!
Thanks Chris. Got a few snaps of a couple of stars last night to see how it works. The bahtinov pattern looks like a very low res version of the spectra i viewed online. So in principal it should work better if i can increase the resolution by narrowing the slits
I can see how you will see a spectrum but not how you could analyse it. The i-Phos measures the spectrum - specifically the angle through which each wavelength was bent through the diffraction grating - and uses that to deduce the relative intensities of each wavelength. If I point mine out the window I can see the absorption lines of Oxygen and water vapour in the atmosphere. However, I don't see how to collect enough light from a star (another star, that is) to do the same. In conventional astronomy I think they track the star, and do a long exposure to integrate photons.
I have all the necessary tools at my disposal. We've been doing spectroscopy with scopes for nearly 200 years. I can kill the water vapour with my UV/IR cut filter. It transmits 98% of light, and my camera is very sensitive It's a planetary camera, a ZWO ASI1034 it's essentially a high quality webcam which can expose from 1/64,000th of a second up to 60 seconds.. I even have high contrast and narrow band filters too experiment with.
czcams.com/video/k0FIluj9ndQ/video.html
Check out this video of the image on the camera as he focuses his scope, it produces a nice image, there is plenty of light to be picked up on the chip. The software you use in your video should function just the same. I can record the image as well using splitcam by grabbing the graph. Then i can use image stacking software to average the readouts over time. 1,000 frames should be plenty.
I can also try the DVD diffraction grating method in between my filter(s), and the camera sensor.
Should prove to be and interesting use for my scopes. My usual diet of Planetary imaging is too difficult this year because they're all so low sadly.
Wow. Fascinating stuff!
Hi! So I was wondering is the camera inside the box still or are you having to move it to get the whole spectrum?
Hi Winturfreak. The camera is stationary. You can choose the angle you set - it's a compromise between image brightness and resolution. In fact, due to the nature of diffraction, you get the whole spectrum more than once - each time it's less bright. You limit what the software analyses by defining a box on the image plane - it only looks inside that box.
Thanks for the video. Where can I download Theremino Spectrometer v1.9 software? I'll be very grateful.
I don't have the link to hand, but Google will find it for you.
@@chriswesley594 hmm aint it the exaxt software you send with these DIY spectroscopes you now selling??
so he needs to purchase and pay you? or you simply don't bother for a viewer / subscr...
whatever.. here you go buddy 2.9 www.theremino.com/wp-content/uploads/files/Theremino_Spectrometer_V2.9.zip
@@JAKOB1977 I'm not sure what point you're trying to make. The software is free, and it is open source. The licese even permits selling it, which I have never done.
As for not doing a google search for someone who can do it themselves - so what? I'm busy and he's perfectly able to do it himself. Or maybne you think his status as a viewer gives him rights on my time?
If you'd like to clarify I'll hit your nail on its head for you.
There's one thing I don't understand: accounting for the possible color distortions of the webcam (by calibrating it against a reference light source; I don't think a random fluorescent light will do though) is one thing, but these webcams are usually crappy as hell. For instance they have a small sensor, pick up an awfully lot of noise and the sensors definitely have their own, unique characteristic light absorption spectrum as well (i.e. different wavelengths will produce a different signal intensity). How do you account for variables like that?
Hiya CoolKoon. The thing about flourescent lamps is that they are all not random but one of only two kinds. The composition of the gases in the lamp is fixed within kinds, and the spectral lines of its elements are determined by physics and never change.
In practice, you point it at a lamp, you see which of the two possible spectra you have, then you use the lines for mercury etc. to calibrate the unit.
Okay, fair enough, that takes care of the coloring. But how about the rest of the variables e.g. the noise level of the webcam, the low intensity range at which it works (the difference between the brightest and darkest points it can capture at the same time), the sensitivity's spectral variation etc.?
@@CoolKoon The exposure is locked to a level where noise is below the predefined gate. Only real light will then be detected by the sensor. This of course means that the intensity is a relative measurement and not absolute, so it's not perfect in all regards. It will also function poorly in regards to low light emission sources.
Hello , thank you for the video , Is this able to detect asbestos ? problem is the detail that distinguishes asbestos exists in the range of 3000 nm wheras the majority of DIY spectrometers does not go beyond 800 nm , I'd like to know your opinion on this and if you have any ideas , I'm now to spectroscopy and i'm thinking to use simple DIY spectrometers and try to extract information using some machine learning on top of this since the reliable information exists on the range of 3000 nm and this is not achievable through DIY spectrometers.
It analyses to composition of light, in the range of about 400 - 1000 nm - so = based on what you say - no it won't do that for you.
Good video! I'm looking to make my own DIY spectrometers using webcams, but looking at the daylight spectrum around the 9:00 mark raises a big question.
The triple peak in the blue, green and red areas do not correspond with the actual spectrum of daylight (see, for example, britastro.org/node/11331). So this points to the shape of the curve in your spectrum is more to do with the separate sensitivities of the red, green and blue sensors on the webcam chip than with the actual spread of light in the spectrum being measured. Is there a way to calibrate to correct the shape of the curve for this differential sensitivity of the RGB sensor pixels?
Hey Eddit thanks for your comments. This point has been made before. The spectrometer featured was my prototype and I had little experience using it. I can't be sure and I no longer have it, but I suspect it wasn't set up correctly in the software. The sensitivities of the webcam sensor are cancelled in the software. In fact the software measured intensities only - it sees a greyscale picture. Another point - every time I measure the sun's spectrum I see something slightly different. That could mean the instrument is rubbish, of course, but I don't believe so. If you Google "sunlight spectra" and select IMAGES you will see a large array of images which differ very substantially. So I think a lot depends on the conditions on the day. Spectra captured of CFLs, LEDs and TV screens all show excellent correspondence to standard spectra taken by reference scientific instruments. A number of my "i-Phos" videos feature those.
@@chriswesley594 Thanks for the clarification. It's a question I've wondered about for a while.
I'm an agriculture engineer, this is very usefull. You can design your plant growth chamber light spectrum. Thank you very much.
Rifat, you are very welcome. There will be more updates to this project soon. Have fun.
Great video. You are using the free Theremino spectrometer software. Could you provide the link to the software download because Theremino website does not have the download link to their own software even though they say it is free.
www.theremino.com/wp-content/uploads/files/Theremino_Spectrometer_V2.7.zip
Hi! This is such a great project. I have a similar project and I partially did it but I am stuck at the calibration part. Can you please share the code you used for this? It would be really helpful. Thanks!
I don't have any code to share, it's done in the software which I did not write.
what's the name of the software?
Hi chris are you selling this item please, as could not find a contact on the selling website. Just wanted to ask a few questions prior to purchase
Thank you
Max
Hi Max, yes I'm selling it. There are links in the video cards and description to the sales video (czcams.com/video/Tz43jRf8FjY/video.html) and the sales page itself (chriswesley.org/spectrometery.htm). Please ask your questions in the comments of the video in question.
Is there any difference in using a Diffraction Grating Slides-Linear 500 line/mm cause you are using one with 1000 line/mm ?
Yes, with 500 lines, the angle of diffraction is different, and the brightness of the spectra is lower.
Thak you for the fast Answer.
Is there any support or forum for this thing anywhere? I went as far as I could using a Microsoft LifeCam HD3000 webcam. I managed to get the software to work with the enclose I built from scratch but I am not satisfied with the quality of spectra I capture. I wish I could share screen grabs of my spectra for people to comment on for help?
If by "this thing"! you mean the i-Phos, then I build it, sell it and support it. There is no forum but I am considering it. The software allows capture of spectra as JPG images whcih of course can be emailed etc.
Ever since I saw "My Cousin Vinny", all I've wanted a Hewlett-Packard gas chromatograph spectrum analyzer (with bucket seats). I'd be the coolest dude in town 😎.
very Nice
Thanks Walter, I'm glad you enjoyed it. Did you see that I make a production version of these for sale now? If you're interested, check out the videos and info on my page: chriswesley.org/spectrometer.htm?poid=YTDIYc-19-3-28
Brilliant!
Hi Francesco - I'm glad you enjoyed it. There are a few more videos about spectrometers in this playlist, in case you are interested: czcams.com/video/Tz43jRf8FjY/video.html
Thank you for.amazing instruction..OoO
You're very welcome Cat - thanks for making time to send me your kind comment.
Excelent video. Can you share the Theremino link?
Hello Joao. My version is a little differnet - but you can Google it.
Any way of using this to sample Reflectance (a series of reflectance values at various wavelenghts) Curve of a color sample on paper to mimic an expensive spectrometer used for measuring color or pigments reflectance ? Would make a great and inexpensive tool.
Currently this looks usable only to measure create a reflectance curve for lights emitters.
Also making is smaller and portable would be great.
Hi Mayorc. The instrument itself measures the light entering its aperture and it doesn't know or care how that light got there.
So if you could arrange your setup such that only reflected light entered it, then that should work, providing the intensity of that light is within the instrument's sensitivity range.
I have not done experiments on reflectance, but I have collected a great spectrum from a street lamp at night quite a way away, and the spectrometer wasn't even struggling. (czcams.com/video/Tz43jRf8FjY/video.html), so I would be optimistic about this.
This is great Chris, thanks for sharing.
Chris, can this be made a little more compact? I mean, is there a way to build this smaller?
Hello Arne K and thanks for writing. Yes, it could be made smaller. You can build a spectrometer you can look through which is only 3 inches long, and probably far smaller. And if you stick it to your smartphone camera lens, you have all the hardware you need. You'd need some software to analyse the camera's image though.
Thanks Chris. Well I'd like to read the spectrum on my pc so for now I guess this is the way to go though... ;-)
don't you still need a diffuser?
Neat video! I am just wondering where you got the computer program you are using? Thank you
I shuold have included a link in the description. However I've just been looking for it and can't find it. It was on theremino.com somewhere in the doanloads sestion. You could ask them. Sorry I'm not more helpful on this one.
Not a problem! Thank you for the link, I will try to search for the download on the page.
Here is the page link:
www.theremino.com/en/downloads/automation
Thanks
Great progect.I cant find the program can you help me. Thanks
@Theodoros, scroll down, or search for "spectrometry"
How did you deal with the usb cable coming out the back? did you just poke a hole and tape so no light came through?
It's surprisingly un-critical. In this prototype I think I pinched the cable in the corner of the box hinge. On the production unit, there is a close-fitting hole in the sensir plate, which is 3D printed.
Near Slit , What is there ??? Diffraction grating or Mirror ?How to select wavelength for this caase? for example 400-700nm for analytical analysis of chemical solution or dye /Where you had connected DVD Diffraction grading? Have you connected the mirror? At the edge of the slit? Or you have connected in front of the camera-Lens?How to get absorbance -wavelength curve for a cuvette
How about "Hello" or "I weonder if you would help me" or some form of politeness? Sending a stranger a loing string of qwuestions you'd like answers to so you can build an instrument like this rather than buy the one I sell - well - what's POSSIBLY not to like, I wonder?
Hi, thanks for this job! I think that in order to see the UV, you should change the glass lens of that webcam, and instead stitch it a silica lens, that is transparent to UV, glass it's not! But, before you need to measure the focal of the original, must be about the same. There are polycarbonate lens also, good trasparency to near UV and less expensive. Bye!
Hiya Marvek and thanks for your comments. My understanding is that the transparency of UV light depends on the type of glass. As you point out, most UV light is blocked by ordinary glass. Quartz, for example, is transparent to UV. However, this spectrometer was built to test the power LEDs used to build grow lights, and UV is not really important in this context.
how can I determine what substances are in the drink with a spetrometer?
I don't know Stefan, but I'm pretty sure Google does. I know "Raman spectroscopy" is a way to find the composition of a substance by shining light of one wavelength on it and measuring the emitted light coming from it. That might give you a start.
Exellent!
can you explain how to calibrate?
thanks!
Hello Andres. You point the instrument at a florescent light source and you get a spectrum graph which is very "spikey". You use those spikes to find wavelengths characteristic of the source - Mercury, for example, at 546 nM. Then you use the software's "trimming" function to drag sliders so that the peaks appear where they should do - at the known wavelength. The whole process takes maybe 20 seconds.
Did you see my new video about my for-sale spectrometer, by the way? You can find it here: czcams.com/video/Tz43jRf8FjY/video.html
Hi Chris,
starting wavelength about 400nm. can you adjust from 200nm? How?
No, webcam CCDs are not sensitive down to those wavelengths
Hi! Can someone please help? I have a Logitec webcam and when I plug it into my PC, the PC does register the USB plugin and open up the webcam, but not in Theremino. Do I need to download a plug in or how do I get my webcam to record in Thermino?
Hi Bianca, you're welcome to ask this question here, but I suggest you provide more information what webcam? What PC OS? etc.
Bianca, your computer is recognising a webcam because that is what the spectrometer is. If you want to arrange that plugging in your spectrometer opened Theremino, then you would need to change the file associations on your PC. But this would mean that ALL webcam devices would open Theremino. So all-in-all, may not be a good idea.
HI! Thank you, I did manage to get it set up :)
okay so you calibrated the spectrometer wavelength-wise, but how do you calibrate it intensity wise? like if the spectrometer is not calibrated in both axes, you cant differ white leds of different temperatures because the peaks look smiliar but their weight is different
Klazzera - you don't. The (free, open-source) software provides a measure of relative but not absolute intensity. Other videos in my playlist to show comparisons with spectra collected from expensive laboratory spectrophotometers, and the agreement in relative intensities is excellent, but without that reference from a known source you select the exposure of the sensor to keep the spectral values out of the noise floor and the saturation point - and of course - that means you don't have absolute intensities.
It's a limitation in this instrument we accept in an instrument costing well under 1% of a lab insturment, and one which is inconsequential for many applications.
@@chriswesley594 i'll be sure to check those videos too, thanks
seems most webcams have that lens array barrel design where the IR filter is inside between the lenses in this metal or plastic barrel.
a pain the ass to remove, and almost destructible..
any hints on which cheap webcams are IR lens Removeable easy.?
It's getting worse as cameras get smaller and their filters get more integrated. The camera I showed in this video is no longer made.
@@chriswesley594 ON the EU market, an alternative for DIY could be the Trust pro Spotlight, I reckon that model at some point also had that easy peasy separate square IR lens.
but then again that camera is like 20euro retail (1.3mpix) and not sure if that is still with that lens construction but I reckon it is.
picked up a cheapo from aliexpress at under 4USD delivered and very small and easy just plug and play with win10 and roll-up cable and with sensor focus adjustment tbut that one also uses that closed barrel lens array with IR and not easy to seperate..i.pinimg.com/originals/1c/fc/e4/1cfce4ecddcd21d691a8bb18f641f092.png
Hi, I need to build a device to get information about minerals in rock. Is this spectrometer able to do that?
Not as far as I know. The rocks would have to be transparent or have highly characteristi reflectivity.
maybe if you built an oes
Thanks Brew. If, like me, you didn't know what OES means, it means "Optical Emission Spectroscopy". There is a good video explaining it here: www.the-experts.com/optical-emission-spectroscopy-oes-explained
Yea that is the one! ...a while after navigating away from the video I thought back to my comment and realized I'd been very vague. You basically have to scrape off a bit of the rock and send it into a plasma and then you do the spectrometry on the light that the plasma emits, if I understand it all correctly.
Another type of spectrometer I know is used specifically in getting info about minerals is called xrf which stands for x-ray florescence or something. But basically it shoots a beam of highly energetic x rays into the rock and they fluoresce some photons back at the device into a spectrometer, and based on the wave length you can for example say there is x percentage of gold in a cave wall.
hi, can we analyze UV light between 200-290 nm range using this method?
No the sensor is only sensitive donw to about 370 nm.
Do you have a link to the theremino website ?
Can I use it for analytical chemistry and titration?
The honest answer is that I don't know. The video & sales page tells you what the instrument does - you'd need to decide if what it does is suitable for your application. If there is a simple experiment I can conduct for you please describe it for me and I will conduct it an upload a video showing the results.
Thanks for share...
You're welcome Marlinlab.
hi friend
Can you set a piece of paper on fire and a piece of cardboard on fire and see if their spectrums differ? Just with a match or laser. Maybe set some other things on fire too?
I understand that for solids hot objects give a continuous spectrum but gases give emission lines while cool gases surrounding hot solids give absorption lines. I am interested in the spectrum of solid though are the plots distinguishable? Have you tried subtracting out the blackbody radiation using plancks law or something like that to get the peaks from the continium?
@@anoshmevawalla6609 There is a lot of material online about these topics you can study, including example spectra for the cases you are interested in.
What is the app that you work with it on you computer plllllzzzzzz
There are a number of packages available. Search Google for "spextrometer software".
Why does the camera have to be angled? Why not just face forward? I've seen "30 degrees" as a magic number, but don't get why...
It could, but, because of the way the spectrum is diffracted, the box would then ahve to be much wider to hosue the camera which needs to intercept the beam..
I can't donwload that program, can you help me?
The download link works, so the problem is as your end.
Any advice on if my camera has a sensor that is about 25mm?
How can I possibly know anything at all about your camera's sensor?!
@@chriswesley594 This is horrible customer service.
JK. I have no idea.
why grating is tilted with respect to slit..can't we keep it perpendicular to the light coming from slit ?
Google diffraction. The first order spectrum - which is the brightest - appears to the side of the optical axis. Actually on either side.
wait, so why did you put it in a box if the box makes the software more innacurate?
nonoham, you lost me. I don't know what you mean, but if you can clarify I will answer your question for you.
@@chriswesley594 i mean, the camera is basically a black box already, couldn't you have put tape over all but a slit of its aperture? do you know the SCIO? its almost sensitive enough to detect blood glucose and is basically just a 8cmx5cm camera in the casing with a battery
@@monoham1 No, you need the slit a distance away from the camera and there is another diaphragm inside the tube and you need the diffraction grating too. Basically, these form the optics which make the instrument work.
Does the length of the box matter?
Yes. This simple machine uses the length to collimate the ncoming light source.
On the light spectra, what unit is on the y-axis of the graph?
There are no units. The i-Phos does not offer an absolute measurement of photon flux density, it offers a relative measurement, though you can do rough-and-ready approximations if you have light sources of known intensity.
@@chriswesley594 That's a bit disappointing but I'm grateful for the insight. Thank you.
@@Monzourful Monzour, if you need intensity you'll need something like the Ocaen optics instruments. Their USB2000 retails for about £1000.
@@chriswesley594 I'm fabricating a low cost Flame emission spectrophotometer and I can't afford to purchase ocean optics instruments. Although to be fair, I actually considered ordering one because it's hard for me to compute for the change in concentration without correlating it with intensity of the flame.
@@Monzourful You can get a measure of relative intensity with the i-Phos, but you'd need to calibrate it with some other instrument to get absolute intensity. Even then the results would be less accurate than the Ocean Optics machine because the i-Phos uses a webcam as a sensor. It's a question of "horses for courses" I guess. If you need very accurate absolute measurements of intensity then the i-Phos is not for you. Anyway your project sounds very interesting - I hope you'll consider making a video about it to share with the world.
how accurate is this meter?
and what resolution can you get from it?
Patrik you can read the software documentation for more on that.
Chris Wesley thanks. that seems impressive. resolution seems to be around 1nm!
compare that to the super expencive Jeti 1211 spectrometer that has only 4.5nm.
seriously i dont know what an expencive reference spectro can give that you dont get here.
whats your thoughts ?
what do you actully pay for with expencive spectrometers around 10K dollars ?
I agree with you Patrik - and I have no answer for your question. Really the physics is very straightforward, and the demands placed on the apparatus are modest. Calibration is easy. I suppose - like many things - we are content to pay more for things we don't understand.
the things i can think of is the lack of CCT? or can the program calculate colortemperature?
the other is if it reads light wrong but how would it do that with 1nm resolution?
it captures more light info than most of the expencive spectrometers.
in the PDF it says something about the lack of measure the lights quantity or something compared to the i1 Display Pro meter.
dont know what difference that makes.
quote:
"The high cost of X-Rite is partly justified by the fact that it also provides information on the "quantity" of
light, while Theremino Spectrometer can not do it (webcams are not enough linear to be able to measure
the amount of light they receive)."
do they mean lack of measuring luminance?
if so i dont need it as i already have an i1D3 colorimeter
what im looking for is to measure white light from different televisions and just compare the SPDs.
nothing more
btw its not possible for you to rent or borrow an more expencive spectrometer like the Jeti Specbos just to compare the results?
Hello
I have problem in spectrometer diagram and the problem is that half of the diagram is full with color (black and other colors).For example, when I use red laser it shows me all other colours with red peak ( in infrared area 730nm but on laser says 650 i dont know why is that) like this ===^===(bottom lines are the X axis, middle lines are other colours that cover half diagram and that peak is red)but in your video is like this this__/\___(bottom lines are X axis and oblique lines are actual peak with no other colours except red)
This looks rediculous but I cant explain better. Thanks in advance.
Hello Matko, the name you are using here is not the name of any of my customers. If you purchased an i-{hos from me, please email me using the my private address (which you'll know as I will have sent the instructions to you via it) to tell me which customer you are, then I'll do my best to assist you.
Dear Sir,
Actually, I want to plot that curve from Spectra getting from Smart Phone for different concentrations of DYE on a single window for wavelength-Absorbance.PFA. Thanks. Seeking Software tutorial of software for that like IMAGE J Or any other else.
Actually, I want to plot absorbance & wavelength curves in a single frame or window with all possible concentrations of methylene blue DYE. From spectra
I want you to guide me about that software for the requirements. Spectra is also attached as my possible setup. This means an optical path for the spectrophotometer
I could not get the link to the spectrometer to work :(
Darrick, thanks for leting me know. perhaps this was a transient problemn - it's working for me now.
http:chriswesley.org/spectrometer.htm?ref=DIYLightSpectrometerDescription5
@@chriswesley594 👍
And can i use any web cam or i should by yours
The webcam alone will not do what the i-Phos does. If you want to build your own spectrometer you can certainly do so. There are plans on the Internet.
Nice video! Btw, use shorter transitions. 10-15 frames fade will look more natural
I wasn't notified of this comment - I just found it so sorry for late response. Thanks for your feedback.
most of those old webcams that dont work in windows 10, can be run by SN9C201 driver. just search for it on google and the first link from 3dpchip.com works for three different old webcams i have in windows 10.
That's very helpful to know Klazzera - thanks.
This can be usefull for chemical analysis and also for painters to make the right collor mixtures
can the software calculate CRI?
No but I guess you can dump the spectrum data to a CSV file and calculate it from there.
Chris Wesley Ok, does the software calculate CCT?
No John, it doesn't. See my comments below about CRI for more information on that and ways to get what you are looking for.
If you point the spectrometer to a good light it will saturate all and you can´t take a good measure...
You can change the gain and exposure settings in the software, and for the production version (link: chriswesley.org/spectrometer.htm?ref=video1Comments ) You can also change the slit width.
For many lights you can also choose the distance of the light from the instrument to modulate exposure, and finally, you can also use neutral density (ND) filters to take down the photon flux.
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🎉🎉
Really interesting stuff. It gave me terrible motion sickness though. You moved your head around far too much and too quickly :)
Hello Mars, yes I agree with you and that was the last time I used a head-camera for that reason. Did you see the new video - I'm offering a production version of this instrument for sale. Please see the link in that video description if you're interested.
audio levels vary so much I can't follow what you're saying
Thanks for the feedback Robert, but, oddly, that's not what I hear when I listen to it. Anyway, there's no way to fix it even if I did.
it's curious.
It is.
>>> ENGLISH LANGUAGE
Thanks Livio, I do make that clear to any potential buyers on all of my sales literature.
However, whilst absolute light intensity is not available, providing exposure is set reasonably, relative light intensities at the various wavelengths agees well with spectra from very expensive instruments.
>>> ENGLISH LANGUAGE
Hi Livio I feel I have made this clear in all my literature and sales material, and it's one of the FAQs, but I'm happy to have it repeated here. If you wrote this here because you see something which concerns you, then please let me know and I will fix it.
I have customers all over the world using these now and doing wonderful things with them. All thanks originally to you guys at Theremino.