How to build a DIY Raspberry Pi Spectrometer using a Picamera and Spectroscope. 

Awesome! Thanks for your kind words! I used to read the Amateur Scientist over and over as a kid!

Thanks very much! Totally! Knowledge should be free!

Awesome, thanks! Yep this should work with any physical hardware setup just fine. Happy hacking!

Yep for sure. A much earlier version did this, but I found it too slow. My particular need was speed (pulsed Laser), but if you were doing astronomical observations then integrating is probably a good idea!

A little tilt allows OpenCV to achieve subpixel resolution when it is calculating the location of straight line intersections in an image. Tilt will help here too, if the system is limited by the optical sensor. Which is to say that fancy math won't help if the optics move around when the cat jumps on the table.

Thanks!

You are welcome!

Thanks! Hope you guys find it useful!

Thanks! Please like and share!

Awesome, thanks! More to come!

Don't you mean SpectRacular? :)

Awesome! You are welcome!

You're very welcome!

Thanks Justin! For sure. I deliberately made the GUI small enough that is should fit on most decent LCD modules you can get for the Pi (clicking the graph on a touchscreen would be a pain, but there are ways around that!). A Desktop instrument would be pretty sweet!

Thanks 👍

bro, can you please share your project list with us?

Thanks!

Great! Hope you guys enjoy it!

Thank you!

Thanks!

Great!

For sure! There's a huge gap between Green and Red that Laser diode manufacturers have been trying to figure out for years.

Extremely important to obtain maximum fps in the program interface!!!

@@appabison8694 indeed. I tried MATLAB in a really early version, but it was far too slow.

I'm glad you like it!

Glad you like it!

That would be cool, and yellow as well!

Shrek green would be a good addition too

Great! Yep, for sure, but I thought it would be cool do do it on the Pi with Open Source Software.

have you done any work on this?

:-D all creatures love Spectra :-)

@@LesLaboratory oh Yes..everyone is stunned by such a miraculous appearance... Have a nice week, keep going with this nice videos and Stay Safe! 👍 Greetz from Germany Ps: give me that mnl 100...instantly!!! 😁😋

Glad you enjoyed it!

Thanks, it is much appreciated. Yeah, the RU-vid algorithm doesn't seem to be trying to push my content. Meh, patience and time....

Thanks!

Awesome thank you! Yes another use for the Pi! :-t

Version 3.2 is up on GitHub, which temporarily resolves the Bullseye issues!

@@LesLaboratory epic, thanks!

Just get the break out 😂

@@LungsMcGee haha

Thanks 😁

Thanks! I am sure one of them will be interested in it for sure. Would make a great project!

Thanks so much!

You are welcome!

LOL chill! It was already in the pipeline for some time as I need a tool to measure the tuning curves of the homemade Dye Laser (upcoming video ;-) ) Besides, although there is plenty of x86 Windows software kicking about, nobody seemed to have written software to do this on the Pi, so I figured, why not, it seemed like a good idea! Also Raspberry Pi's are just awesome. You are welcome! It seems pretty popular on here too.

😂😂😂😂😂😂 this made my day

The one I have was gifted to me, so I worked with what I had. The pocket version should work, with some experimentation. I have not done a flame test, but now it is added to my to-do list! ;-)

Interesting project. Just curious, do you have a specific astronomy goal such as identifying certain types of objects by their spectra?

@@WilliamDye-willdye Long term, I'm looking to have a small on-the-scope sensor that can be used for quick spectral analyses. Short term, it's to see if I can get a working system for such data collection just on the scope. The AS7341 is the first device I thought would be a good one worth testing due to its bandwidth and cost. I did us an RGB sensor a few years back but never moved past an initial test due to the limitation on the sensor. I know this would not replace a real Astro-spectra setup, but it has been fun and the sensors are getting better.

All sounds pretty cool! :-)

I had the same question --> can we upvote this question ? :)

@@haroldemmers3678 I concur. It is a very solid question and I'm now curious about the answer. Perhaps he considered removing them but decided against it for some reason, and that reason itself might make for a good followup video.

Bayer filter also might affect the spectrum, going with black and white sensor is doable with calibration. Hardest part in this DIY setup is intensity calibration since sensors might pick up different spectrums with different intensity.

All good questions! I did not remove the IR filter, as the scope I am using was designed for visible wavelengths only, and my interest at the moment is the visible spectrum. Internally the spectroscope is a transmission Diffraction grating, plus a collimating lens and a prism (for a linear design) this is too much glass and plastic film for UV to make it though and would significantly attenuate IR. If you build your own spectroscope frontend, you could do whatever you like. For this you would need a reflective Diffraction grating to deal with IR and UV, and quartz optics as well. Yes, Picams have a Bayer filter. Jon Smirl on GitHub suggested removing this for UV work, and cited a paper here: www.mdpi.com/1424-8220/16/10/1649/pdf but it is not for the faint of heart! Also yes, you would then have to characterize the response curve for the Picam sensor, minus the Bayer filter. On the plus side, you would have a really high resolution B&W Picam if you sample the original RGB values as individual pixels. That, in and of itself might be useful to the Astronomers.

Consider removing the CFA or using a monochrome sensor ;)

You are welcome, yeah, I hate unobtanium for builds like this, sometimes it's a necessity, but if it can be done with off the shelf parts, then all the better!

That could make a pretty cool project!

EXACTLY what I have in mind. Material identification with a Jetson Nano, if possible. If not, another SBC. Same idea. That's exactly why I'm here.

You are welcome!

Thanks! The spectroscope was gifted to me, but that is the manufacturers site for this model. There are plenty of similar ones about, or you could make your own. You can easily get spectra from an LCD monitor. I would imagine you should be able to for a glowstick as well in ideal circumstances. If I can get time on my side, I might add things like brightness, contrast etc, but I would need to rewrite the interface.

Thanks! I will do a video on the inner workings of the program when I get some time.

Thanks! It should work with any home made spectroscope. So long as you can fit the spectrum in the preview Window. RPi4 is best for this as that is what it was deigned for.

Good idea. For this, one will need the quantum efficency curve from the camera. But I m not sure the manufacturer has measured it for such a cheap camera. Also, the camera uses a bayer matrix, which means there are red, green and blue pixels. These have to be callibrated individually. So i guess it is easier to look for a monochrome sensor with a quantum efficency curve available.

@@TheMAggi99 Definitely going black and white sensor is a good option. In my young days when still doing detector work, I removed the glass protective plates in front of the ccd array: you can buy 50 of them on the cheap (and break several off them while improving your methods), compared to only one equipped with a quarz window. I was dealing with soft x-rays lasers, and these tend to actually increase the dark current of your pixels over time, burning the camera chip, even at low average (but high peak) intensity.

What you are talking about is XRF (X-ray Fluorescence), which is a whole different ballgame, but fundamentally similar, it just uses X-rays instead, and a suitable Scintillator instead f a diffraction grating to detect the different photon energies. It would be possible to identify a metal with an optical spectrometer by vaporising it. This can be done with a High power Laser. Mars Curiosity does that: mars.nasa.gov/msl/spacecraft/instruments/chemcam/

It 'should' work with any USB cam that the Linux driver supports. Of course there is variation in quality of cameras. The beauty of Picams though, is that there isn't much variation between models, even from different suppliers.

The steel would have to be heated beyond incandescence I think. Have a google at Laser Induced Breakdown Spectroscopy (LIBS)

Awesome! Have fun with it!

Either that or an ND filter and you can maybe calibrate from prominent Fraunhofer lines perhaps. Relative intensity is a different story.

It can go a little ways into the UV ~380nm to a little ways into the IR ~810, but the spectroscope was designed for visible light. You could build a spectroscope with an extended range though.

I have tried one and can see a little way into the IR, but I haven't fully tested it yet. I have another NoIR cam on order at the moment, as I sacrificed the one I have for an upcoming video...

jonsmirl on github sent me this: www.mdpi.com/1424-8220/16/10/1649/pdf Worth a look!

Thanks! Not as much blue as you might expect. The sky only appears blue because of Rayleigh Scattering.

It could be done, and it is open source, so you can modify it if you like. The reason it was not done is speed, large live images in OpenCV are a bit hungry for CPU and RAM, so I wanted it lean. I suppose I could remove a strip of video, say 20px high and 640 wide, and display that under the graph, that could look pretty cool!

I have never used that software, so I am not sure whether this would be suitable. I think there are already miniature sensors that can do that at a fraction of the cost.

Yes, the NoIR cam would be more sensitive. The Spectroscope I am using is designed for visible wavelengths though. The deepest into the IR I have seen is 760nm. To get a larger range, you would have to build the spectroscope frontend. UV is particularly problematic. Most glass types, and all plastic will absorb it. You would have to use Fused Silica optics for UV work, which costs $$$! IR should be no problem though.

@@LesLaboratory Ahh yes, of course. You're working in UV... no idea how I got IR in my head. That explains the effort behind the dye lasers.