Відео

it will make you look cool and girls will like you. At least, that is why I bought it! :-)

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

Wow, I would love to build one of those...

@@project-326 The project is called ramanPi.

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

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.

Thank you very much! And congratulations on reaching 20k subs!

@@project-326 thank you sir!

I think so too, but my content isn't really a good match for what YT needs in order to meet its business goals.

Thank you very much, everything helps with the 'camera fund'.

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?

@@project-326 ​ @project-326 well ebay of course! a lot of browsing and even more patience! Here to help with your quest!

Holy f*ck, that's a great idea! I'll get back to you with some concepts for a video soon! Thank you for the great feedback...

I got it on Taobao, here in CN, I'm pretty sure that AliExpress has similar things you can find with a search...

thanks dude, that make a big difference - I hope that you got something useful from the video.

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.

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...

no, they literally came with nothing in the way of instructions - I had to figure that out...

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...

@@project-326 Very interesting. I guess if this really worked at ground state those gas tubes would have obvious color tints to them.

@@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.... 🙂

Really? Who posted it? OK, I just saw it too - thanks for the info!

Thank you very much for the positive comments and support.

Yes, you are correct. The camera module used in the LG spectro has its limits, I manually adjusted the exposure and set it for the maximum of 500ms.

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).

I will have to try again with DC, the little AC generator starts up at whatever voltage it is set for. Our DC HV supply might be useful for this...

Thanks for the lovely comment, but just one point... Having an equal share in the family decisions doesn't make anyone dominant, husband or wife.

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.

Grrr, the evil algo...

but -5 cos I said it ain't a garden of Eden...

In my kitchen, want the link? :-)

let's see if they respond!

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.

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...

fingers crossed that they respond!

yes, the other links are from price gougers, please avoid them...

Really awesome - it all goes towards the new camera fund.

Really awesome - it all goes towards the new camera fund.

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.