Experiments, technical reviews and some profanity.
I live in southern China, when the COVID-19 pandemic hit, many of my friends left China. So, I started this little channel as a way to keep in touch with them. My first videos were about the situation in China and were all showing the area around where I live. After that, things have grown a bit, but the objective remains the same - making friends.
I got mine on TaoBao, so only available in Mainland China, something like this on AliExpress will work fine. www.aliexpress.com/item/1005005901234431.html?spm=a2g0o.productlist.main.85.42b6ed6ied6ikS&algo_pvid=8451ae79-bfcb-40e2-9401-942fc316c580&algo_exp_id=8451ae79-bfcb-40e2-9401-942fc316c580-42&pdp_npi=4%40dis%21USD%213.03%210.99%21%21%2121.05%216.86%21%402101e56617277266843088405ea078%2112000034796836076%21sea%21US%216048870960%21ABX&curPageLogUid=fbB61WDuSNHl&utparam-url=scene%3Asearch%7Cquery_from%3A&gatewayAdapt=4itemAdapt
I don't think they finished the project. It was called RamanPi ( I believe it was going to be 3D Printed and open source) but the last update was 2018 and I am not sure if that person will continue
For everyone interested in Plasma discharges like in this video, there is an online experiment with which you can actually control a plasma discharge, change the discharge voltage, adjust the pressure of the plasma and even change the shape of the discharge with an Electromagnet. There you can observe how the emissions change depending on the pressure, voltage and magnetic field. All done on a browser without any signups or something. Just search RGDX and you will find the experiment.
Would be nice if there was an option to use it like a camera: snap timestamped spectrogram data to an SD card and look at the plots or csv afterwards. (Even if it had to be powered by USB)
Oh man, you're going to build your own X-ray spectrometer? I'm going to tune in for that, no matter what kind of results you get! I bought some alpha sensitive photodiodes a while back and still haven't gotten around to building an alpha spectrometer... after working with PMTs and scintillation based gamma spectrometers, with their (relatively) enormous charge output of around 1 pC/keV, I was intimidated by the ~0.05 pC/MeV that I'd expect from alphas... but assuming the same ~3.6eV/e- conversion ratio, that translates to only 0.00004 pC/keV for X-rays! The high energy 22 keV peak on that example XRF spectrum you flashed from the datasheet would produce a pulse height of less than 1mV in a charge sensitive preamp with 1pF feedback capacitance. And then we need to resolve 100eV-500eV to define the spectrum somewhat well. 5uV-20uV per ADC least significant bit referenced to the preamp output. That's demanding, but even more hair-raising is that this amounts to something like 30-150 electrons per LSb! I'm not saying don't do it or that it won't work, just ... man, that'll be one hell of an exercise in low noise amplifier design! I hope you attempt it, and whatever the outcome hat's off to you if you do!
You are totally correct on the noise issues, I am trying to push the bias voltage as high as possible to increase the SNR on the front end. The charge amplifier is also another challenge, but there are reasonably affordable options for that too. We have created some PCBs already for the purposes of experimentation, when trying to place things like 100 MOhm resistors, proto-board doesn't cut (requires custom PCB layouts even for initial prototypes) it and solder flux needs to be really well cleaned away. In my mind, being an x-ray spectrometer is kind of the stretch goal, just making a gamma sensitive detector will be a good start, I can then build on that platform. After 35+ years of hardware design, I am pretty used to the step-by-step approach. This is one of those projects that is very sensitive to PCB layout. That said, my day-job often entails designing complex RF circuits, operating at 8 GHz... Hopefully, at the minimum I should be able to achieve something that will be the size of the NukAlert but actually works, and does so from a coin cell.
@@project-326 that'd be cool! Small low power circuits make me happy. I considered the Cremat CR-11x modules, but those are about $50 I think (not terrible... but a little disappointing after having paid only $7 or whatever it was for the diode). The CR-110-R2.2 is supposedly able to deliver 200 e- equivalent noise charge, which is in the ballpark of what we need here. Is that the brand/price point you were looking at? Or did you find anything else? I would really appreciate learning of any other options. My understanding of silicon detectors is that increasing the bias voltage doesn't increase the SNR per se. It increases the width of the depletion region, which does several things: it decreases the junction capacitance (nice for stability, transient response, and supply rail noise coupling), it increases the high energy photon stopping power due to the deeper sensitive depleted region, but it also increases the dark current due the larger number or recombination/generation centers enveloped by the depletion region. I believe the gain remains the same ~1 e- / 3.6eV hv as long as the device is operated outside of avalanche region (and I sort of doubt an avalanching diode could be used for spectrometry, although maybe it could with really good bias and temperature stabilization). So I don't know that pushing the bias voltage is that valuable.
You are correct that the pressure does not change what lines will be emitted, but the pressure can change how much each of these lines get expressed, so the proportions of each line can change, meaning that the overall hue of the plasma can be altered by pressure.
About time someone look into the gas inside light bulbs and Geiger tube! Well done ! Your channel is growing fast and after all your hard work you deserve some views and $$$$! Happy for you sir!
From a respected person like yourself, that is high praise indeed. Well, I recon at this rate in about 8 months I can finally buy a camera... BTW, where do you find all that wonderful 2nd hand equipment?
For everyone interested in Plasma discharges like in this video, there is an online experiment with which you can actually control a plasma discharge, change the discharge voltage, adjust the pressure of the plasma and even change the shape of the discharge with an Electromagnet. There you can observe how the emissions change depending on the pressure, voltage and magnetic field. All done on a browser without any signups or something. Just search RGDX and you will find the experiment. (RU-vid censors Links, otherwise I would post it)
Who's in to build a cheap FTIR spectrometer? You can't touch even the worst of the commercial ones for under USD1000 used, and there absolutetly has to be a way to do it for less money than that. With one of those, a reasonable library of peaks, and not-super-complex software, you can get a good idea of what organic thing(s) you have in the sample and how much. Check "Simple, fast, and accurate methodology for quantitative analysis using Fourier transform infrared spectroscopy, with bio-hybrid fuel cell examples" DOI:10.1016/j.mex.2016.02.002 for an example.
sorry but I also need to allow for those that English is not their first language. When things are paced too fast I get complaints, when they are slower, other folk complain. Not sure what the answer is to that problem...
@@project-326 I understand :-) but I can't get the juicy information. It just is way to long, make a shorter video to explain how to do everything without explaining what spectroscopy is.
A great video, thank you very much! Regarding the issues with your webcam: 1) Dim pictures: If the webcam allows for it, you can just increase the exposure-time (also set gain to zero). 2) Wrong colors: Again, if the webcam allows it: Fix and disable white-balance related functionalities. A great webcam that I know allows this is the Logitech C920 - this camera will also allow you to fix the focus-point.
Thanks for the feedback. A couple of points: 1) I increased the exposure time to the max, which for the LG spectrometer is 500ms. 2) The color of the Ne tube was the same when viewed by the MK1 eyeball. 3) I have a Logitech cam that I use for meetings but it doesn't have a manually controlled focus like this one, having the ability to fox the focus makes a massive difference to the results, at the short ranges, auto focus devices make all kinds of mistakes...
Excellent video, I too have been fascinated by spectroscopy for a few years now. I like these rare gas tubes. Do they come with instruction to power them ?
Have you tried using the opposite method of determining these gases by shining light through and seeing what lines they block? I imagine it would be hard to see these without a high-resolution spectrometer as they would just look like slight dips on these lower-resolution ones.
Yes I did. The issue is that the gas needs to be ionized for the emission/absorption effects to be an effect. I think that in the upper atmosphere, the UV and general solar radiation does this and so we get Fraunhofer lines in sunlight. Obviously, the tubes look transparent, the gas does not have any noticeable color, if the absorption effect was always in effect, we would see *some* color variation. I did actually try to measure this during the making of this video before I realized that it was a very dumb idea. The electrons need to be bouncing around between the various energy levels in order to emit or absorb the specific lines. Might make for an interesting video, you are not the only person that has mentioned this in the comments...
@@gblargg this question is definitely worth following up, quite a few people have asked this same question and I do love to learn if experiments are possible to make work with cheap equipment.... 🙂
17:40 Can't you just manually adjust the camera's exposure to overexpose and bring up the fainter bands? I did this with mine to e.g. measure a monitor's RGB spectrum. You can lower the frame rate I imagine and then really push up the exposure time.
physics question for your knowledgeable viewers: These gases emit light in characteristic spectra. Yet they are all colourless. When backlit with a light source with a continuous spectrum, shouldn't they absorb light at the wavelengths they emit in these experiments, causing them to seem coloured?
That's a really interesting question and one that I actually tried a couple of (failed) experiments with. I think its a question of getting the electrons to the excited state. When the atoms are being excited by a strong electric field, the emissions will be very strong, but for absorption, the energy of each visible photon is low you might need a much longer column of gas and a stronger light source, to get anything measurable. The example might be the Fraunhofer absorption lines seen in the spectra of the sun. In this case with have a long column of air (the height of the atmosphere) and a really strong light source (the sun). The UV photons in the upper atmosphere might be providing the energy to get things excited... I'm pretty sure that if you pre-ionize the gas with an electric field to get the electrons jumping around and then perform an absorption measurement, the results would be different. Probably worth building a test-rig for this... It's certainly worth knowing more about (the very same question occurred to me whilst making this video).
As a bored ham radio operator we used to say DC to Daylight. Enhancing my spectrum curiosity I first grabbed Daniel's video from Diode gone wild. Dan did not hold back his feeling about forced software registrations and this creator must have taken over his vulgar words. Still thanks to this Englishmen with a dominant Chinese wife I sat thru his satiric frustration of cheap products made with British science. Well Newton may have started it, then Fraunhofer and Kirchhoff to Bunsen etc. Sad to see youtube being dominated with rather degrading excrements doing the huge numbers. This really undermines the frustration of every serious scientist. My house has 100's of CCD chips and I am too lazy to scratch the bayer filter so huge thanks to get me onto the little garden. Seriously considering to buy the little bro once Ali is throwing a good offer onto my face.
Video camera nerd recommendation would be the Sony A7S III or FX3 (they're the same camera in different form factors). If that's out of budget, the Sony FX30 has a smaller sensor and a much smaller price. Sony permits third parties to make lenses for their system, providing far more lens options at competitive prices.
Thank you for the awesome advice and the support. I am going to need to do a bit of research on cameras, I have never really taken the time to look into this too much. My current spec for the body is full frame, 12 bit log color space and cheap as possible...
@@project-326 12 bit log is still a rarity among the reasonably priced mirrorless bodies. Most are still 10 bit log. The Sony bodies (A7SIII, FX3, FX30) can record 12 bit RAW video with an external recorder, but RAW video is massive and unwieldy. Panasonic's new GH7 records raw internally, but it's not full frame. Nikon's new camera records raw internally, but Nikon is not truly a video camera company, yet. The cheapest, good quality, full frame, autofocus camera with a heavy emphasis on video is likely the Panasonic S5 IIX. But the Sony A7S III and FX3 are far better in low light conditions, have better autofocus, and faster sensor readout speeds. Sony makes the sensors for most of their competitors, and they often hold back their better sensors a few years. The A7S III / FX3 sensor has yet to make it to a competitor's camera. But they're now 3 years old, so often available used at more reasonable prices.
@8:40 That's what I used to call finger-print-glow.. (i.e. WATER) I went through a gas-discharge phase and tried making my own gas samples to later light-up with HFHV (mini SS telsa). The one colour I saw the most is what you got for He.. When I looked it up, it was what WATER should look like. I then tried to put the smallest drop of water in as a sample, and really tried my best to make it clean (i.e. no-white-fail). I was the same white.. So while I can't say for sure (you'd need a mass-spec), my money would be on your He being just water.
Hangzhou is more of a software city, but there are plenty of Shanzhai engineers just down the road in Yiwu who specialise in knocking out replicas to this kind of tech. That is probably where the HZ office sources its components anyway. ;-)
It was a couple of months ago during the early monsoon season. I was getting some b-roll for the Micro Spectrometer [Part 2] video, I wanted to continue the theme about waiting for the sun to shine and didn't want to reuse old footage. The video doesn't really convey the brightness and the sheer loudness of the 'event'.
@@project-326 I can remember plenty of major storms in GZ, and they really cannot be captured unless you are actually there. Fingers crossed it does not start flooding again.
21:58 i discovered this weird effect as well in phosphorescent HPS lamps, it doesnt glow under regular uva or uvb, it needs direct high energy uvc internal of the tube which i suspect is blocked by the outer glass, i think it has to do with the rare earth doping in the glass as only high pressure sodium does this with it's alumina tubes, i have yet to test low pressure sodium
Also someone else said it may be an electrostatic effect, there really is nothing in literature other than one or two old papers talking about the doping in the arc tube
It's an interesting effect, it had nothing to do with the theme of the video but I wanted to show it anyway. From the number comments that have been posted about that part of the video, it was a correct decision...
Thank you again for a great video. They had four in stock this morning but just checked and it is sold out. There are other links but they are more expensive than this one for $60.40+10.60(shipping).
Thanks, impressed by your content! May be use your idea with the lens to get more sensitivity out of littleGarden‘s Spectroscope for seeing absorption lines in gems. So far, just ruby worked well, having clear lines and string fluorescence. This spectroscopes are really cool for exploration of light and waves, love it!
I would suggest you find something matte white, or paint some paper with calcium carbonate (lime) or barium sulfate as a diffuse reflector to capture more light. The a lens in front of the LG spectrometer will help a lot. I would also try placing a frosted glass window in front of the LG slit and focus another lens on it. so you have a two-elements system. A better solution might be a cylindrical lens made from a PMMA rod, although this will most likely block the UV completely (commercial PMMA unless otherwise specified, is usually sold with UV absorbers).
how did you try to see the absorption lines in gems using this? which type of light did you use ? I am also curious about testing this with gems. I will order the unit first and try to do my own tests
@@mrm1712 mostly an 20watt halogen, then an UV 365nm diode lamp, and a fluorescent lamp, but not so happy, as especially the bright blue range (~450nm?) isn‘t covered well, so I oredered now some mixed bulp of halogen/xenon that should give a more balanced spectrum of light. Pure xenon would be even better, but I am afraid of tampering with high voltage stuff. And to fixate the stone in front of the slit I use „toy clay“ so no other light than that from the stone enters the slit
On the gems: it worked for ruby, and now for an morganite with an very fat band around 520nm. But narrower bands are not seen, even with the max resolution and finest filter setting- or they apoear as subtle „dip“ in the spectrum, but the noise is as big and overrules it, so not yet there. I need a better, fixated light source, possibly a narrower slit, possibly a different grating.
