Indeed, good work Max, looking forward to more cooperation very soon.

My pleasure Arthur!

Cheerio Posh Arthur, you are looking very appropriately toff indeed 🤖🎩 If I may, I can offer some insight into your spectral analysis of these light sources that you have. The 532nm green laser pointer has a peak at 820nm because this is the wavelength of the GaAs laser diode used to pump the Nd:YVO4 crystal inside which then lases at the fundamental neodymium line at 1064nm, and which THEN is frequency doubled by a potassium titanyl phosphate crystal to 532nm green. Also, your violet diode laser at 22:00 and your red laser at 20:30 are direct diode lasers, there is no pumping of a secondary lasing medium. The line you see at 820nm for the violet laser is just a second order diffraction line, but the small peak at 750nm for the red laser is not. The higher order diffraction peaks will always be at exactly whole single digit multiples of the fundamental line. I suspect the line at 750nm for your red laser, and the small peak at 622nm for your 532nm green laser, AND the small peak at 500nm for your 410nm violet laser are simply an unwanted internal Fresnel surface reflection off the first side of the couple mm thick DVD being used as a diffraction grating on the "Garden" spectrometer. Notice how they only appear on the Garden, and they're always offset 90nm from the brightest peak. Your analysis of the 450nm laser is accurate. I wonder if it is possible to remove the phosphor from a CFL source like that by immersing the tube in an ultrasonic cleaner bath, which then could be used to observe the mercury lines in complete isolation, as from an uncoated germicidal bulb. Pip pip old chap. Looking forward to part 2.

@@Muonium1 Hi and thank you very much for the detailed explanation. Actually a few other viewers have helped me with this too. Max, Arthur and myself are always pleased to be learning, even by mistakes. Far too many YT creators are very resistant to corrections (Veritasium comes to mind), so thank you for your help!

@@Muonium1 Actually, I have a mercury vapor lamp to test in part 2...

Nobody can fire Posh Arthur, despite how naughty he is...

the humans can't get by without me, don't worry.

Thank you, this a a couple of other corrections will be in part 2 of the video.

me too, I will probably take a look, at least to see if the data has any encryption included.

@@project-326 : I'd definitely be interested in a followup video on what you find out. This would pretty much make the difference in whether I'll buy it from Amazon when it comes out or not. On the other hand, I presume their "magic" algorithms are all in the computer-or-mobile-device side of things rather than in the hardware, so the serial data isn't going to be as precise, and probably isn't calibrated to luminosity levels. So having an "export to CSV" function and/or an SDK to allow another program to access the calibrated data might be more useful. My applications for this would be combining it with a broad-spectrum light source to experiment with looking at spectra of reflected light, which means that being able to post-process the data from the device is of critical importance.

@@BrooksMosesSame, I won’t touch it in its current state out of principle until someone reverse engineers it.

I will be doing exactly as you suggest with a Neon lamp source. As part of another video I'm working on, I will be discussing how to use these cheapo spectrometers to identify elements. I'll post a pic I got from the TLM-2 on the community tab in a few mins, keep an eye open for that!

​@@project-326hehe, nice to hear that idea is in the making ^^

This!

SKD is a great suggestion...

@@project-326 there is an SDK, I got the document from their website using my product number, it's very likely the same protocol. Can share if desired, just let me know of a contact address.

Haha i truly don't have a lot of confidence that they can write good software. SDK or hardware interfacing open documentation would allow some interesting uses. Someone needs a monitor calibrator? Might turn out better than any other.

@@SianaGearz I also have a fairly low confidence, their core team is basically scientists, what they need to get to market is more engineers. Its the classic start-up problem...

VERY interesting! Instant new subscriber with the bell clicked (I never do that 😮) You might have explained it in the Little Garden vid (going there right now), but I’d love to hear the details of how they get 5nm resolution out of just a few quantum dots.

thanks for that info. It is the very best thing about a channel like this, I get to learn from smart people!

frequency doubling, how does that work? absorbing two photons, emitting one? (always thought that was impossible)

​@@Peterkramer929that's basically exactly what it does. The math works out super close to both input photons only being half the output energy respectively. Even more fun, there are processes working the other way round! Look up SPDC and you'll be even more impressed :). Back in the days I built entangled photon sources by the use of UV lasers with a Type 2 BBO crystal. The process occurs only rare times and most of the UV passes straight through. Some UV photons get split into 2 red photons, also being orthogonally oriented in their polarization plane. You can "easily" dm Separate them by using Pol filters :D

@@leandroebner1405 I did SPDC generation in my masters and both generation and recombination in my phd thesis. It's one amazing process, but quite inefficient as you've mentioned. I did some calculations for BBO, but ended up doing type 0 (same polarization of both photons) in a periodically-poled KTP crystal with periodicity just over 3 um. With ~100 mW of 405 nm we got a hundred thousand pairs per second or so, and up to a few thousand recombinations per second. Recombination is ultra-challenging, both theoretically and experimentally, I think it'll be an important part of quantum signal processing in the future. One interesting thing about type 0 in PPKTP is the way you can change the phase-matching conditions with both temperature and angle of the crystal. You can get collinear-degenerate, collinear non-degenerate, or non-collinear interactions, all with the same crystal.

@@leandroebner1405 I used to teach my kids that once an electron got into an excited state it would immediately(!) fall back to a lower state, emitting a few lower f (and therefore E) photons. Or perhaps one with the same f when the electron would, in one step, go to the ground state. But that it is impossible to excite an electron in two steps. What I understand from you is that you need two exact same photons at the exact same time(?) I'll look into it.

There is a USB-Serial converter inside the cable housing - my guess is that because the mini-USB is not common, it help to reduce the number of people that are likely to plug it directly into a USB port...

Yep, we will be adding a correction to the part 2 video.

@@project-326 cool, looking forward to seeing it

Hopefully this will be on Amazon soon!

Thanks for the in depth review. It's a very interesting product, it would be much nicer if the apps were had the basic functionality working really reliably. The mobile apps need to find the unit faster and the PC app needs to remember settings. A USB C socket would be highly appreciated too. P.s. Please retire the slow robot voice and refrain from repeating the same information you just said when you switch to the spectrum results.

@@MaxNippard We are hoping that if there are enough comments about the issues, the manufacturer will make the changes...

@@MaxNippard I second the suggestion to retire anything repetitive.

@@MaxNippard How long have they been developing this device ? Haven't seen a Mini-USB connector for over a decade. 0:07

a good plan!

We are already busy in the 2nd part...

Coming soon!

OK, so I had a lot of very detailed discussion with the creator of the 'little garden' device. It seems I made a mistake in my original video. He is not buying monochrome camera (that is too expensive, due to the very low demand) but manually cleaning of the Bayer Filter. I have a lot of respect for that guy and will be including a whole segment on him in the next video.

I also tried to build one myself - it really made me appreciate the 'little Garden" device a LOT more. Sometimes, its the journey that is more interesting than the destination...

@@project-326 Cleaning a Bayer filter manually sounds crazy, but maybe you know how he does it?

@@user-ri2zq7by1m The creator would like to keep that part secret... But I ill be showing a video of the process that he sent to me.

@@project-326 that would explain a lot, haha I spent hours trying to figure out if I bought the wrong camera module. Cleaning the Bayer Filter sounds like delicate work that take a lot of effort. Cant wait to see the process!

so many things to test, so little time...

Welcome aboard!

In progress, but please be patient, we want to be sure the manufacturer gets their head around the idea of listening to potential customers.

I first heard it in the Scarlett Johansson and Bill Murray movie Lost in Translation. Been on my playlist ever since😂

If I had time for that, I'd look into possible hacky modifications. Those devices send their simple data packets over the com part without any encryption. Don think their company would like that approach tho. But that's what happens by making silly decisions the customer has to life with.

Thanks for the ideas, I hope they will be able to take these on board...

thank you very much

I agree...these things need to be fixed before I would buy or recommend to others.

As I enjoy your videos too Sir!

@@project-326 👍😊

Awesome! Thank you!

;-)

Human music at its finest, in the right setting, of course...

This is great, the more applications the better, a tool is only useful if it has a job to perform! I need to check on the mat, I have two, one is 1cm and the other is 1" (I do photography in 2 different locations)...

It's certainly worth trying that, let's hope that didn't try to encrypt the data to prevent that...

@@project-326 I have a different version of their spectrometer, the PJG3, which came with the information regarding the serial port commands and data packets. This may be useful for your purposes. The data isn't encrypted from the looks of it. The document is in chinese, but translation by machine seemed to have worked very well. Now, I can't actually test it yet because they don't have the pinout for the TTL interface printed or written anywhere! The PJG3 version has no usb output, but rather a 4 pin serial interface that is completely unmarked and doesn't come with a pinout diagram (nor is it included in the manual for the client interface or for the SDK). So, I've written to the company just yesterday to inquire about this. Their Alibaba store is offline now, so I had to write to their email. No answer yet, I sent them a machine translation version a few hours ago, hopefully they'll come through and provide this info. Cheers!

I'll take a look at that in the next part of the video.

Yup, if figured that out from some other comments. I will be making some corrections in the next part of the video. Thank you for the corrections, learning is something I never want to stop doing and having people that know something I don't, point out mistakes in the comments is a positive experience for me.

Thanks for the feedback!

CRI would be neat!!!

@@leandroebner1405 That's a really nice suggestion, let's mention that to Torch Bearer as well!

Thanks so much!

Thank you, I have already be 'educated' in that aspect by another kind viewer. The thing I like best about making these videos is that there are always people with more knowledge to learn from. I didn't realize that the green laser was a 3 stage process. Its amazing how much technology can be crammed into a $10 laser pointer...

@@project-326 They're cheap as chips today but i remember when green pointers cost the earth in the earliest days of the internet. BTW, they now make fully SS 488mn blueish-green ones with just the diode - I own one. I need to develop my own YT channel with all the tech junk I've accrued over the years. LOL. I'm glad you welcomed my earlier explanation on this public forum and I'm certainly learning a lot from your good self. Can't wait for the second half.

​@@project-326DPSS are nowadays some of the cheapest lasers which is crazy when you think about how complex their optical path actually is

​@@DennisSantosyes please. KZfaq needs more creators in that field, always!!

@@leandroebner1405 I was one of those that worked on early CD player technology, the whole CD mechanism and OPU ended up costing less than $1.50 in serious volume, in particular the Sanyo DA11 was just an amazing piece of optical technology for its time that somehow also had the distinction of costing the same as a candy bar... If that same technology had been developed for the military, each CD mechanism would have cost about $150K...

I don't know yet. Mine cost around $50 USD here in CN on TaoBao but on Amazon there are going to be the extra costs of Amazon's margin (4 x higher than TaoBao) and shipping, logistics and fulfillment. I'm kind of guessing it will be over $60 once it reaches Amazon. Just a guess though...

I will try and make changes to the next video, thanks for the feedback though!

That is exactly why I like to make experiments on this channel, nothing beats seeing stuff for yourself, even if the results are way less impressive than from a professional lab. The reason people still buy telescopes is for exactly the same reason, nobody can beat the Hubble of JWST images but those are someone else's results. Seeing a tiny, dim, fuzzy, monochrome image of the rings of Saturn, with your own eyes, beats all of those beautiful on-line images from the pros. I'm going to look into finding a low pressure H2 tube...

that is an interesting experiment we might include in part 2 of this video...

indeed. So much is not defined but that only means that there is more to learn...

its using the old Mini-USB because its not USB, but serial UART. There is a USB-UART converter in the cable itself. Hopefully they can improve that too.

Yes, that is good idea, to create a calibration curve for exported data from the little garden...

Thanks for the tip!

Yes, there is a very detailed teardown coming in part 2 but it needs to be said that opening the device is a one-way process...

I got my hands on a similar model by the same company, it's the pjg3. I was able to obtain the SDK for the system. I'm fairly certain it will work for you too. Let me know a contact point and I'll send you the document.

I'm hoping that they will make some changes...

Welcome aboard!

The TLM2 isn't using a webcam. They are buying a monochrome CMOS die and getting the QD's deposited onto the sensor directly before the passivization is added. I'm guessing that they are getting the image sensor vendor to do this for them in the fab as a custom version. The TLM2 appears to be pre-calibrated for level and that cannot be changed. The little garden device will suffer from the issues that you mention, the levels for each of the color channels will be optimized for the 'best picture' for human eyes, not best optimization for photon energy. These types of sensors usually have some OTP ROM that allows the product level manufacturer to set up the color balance, the gain transfer function, etc and those settings will have already been burnt in before the creator of the LG device received the camera module. The creator of the LG device has released that on AliExpress and there is a link to the store in a post in the community section of this channel.

I don't think they would release their software open source, but perhaps an SDK is a good compromise...

its a definite requirement for it to be useful. such a calculating cie-lab color temperature calculations.

You'll run into a dead end pretty soon when you can't to anything with the data you measured. Agreed. Not a total dealbreaker because that thing in that price range is less a scientific tool and more a fun nerdy gadget

GM tubes have VERY long lifetimes - typically in the region of 10^10 counts for a glass sealed tube. With a 10x typical background, this equates to over 3000 years!

@@project-326 but does the accuracy of the GM tube worsen over the course of 5-10 years and does it matter if it is left permanently on to monitor background or if it is left off and stored for emergency ?

These aren't exactly the same, but similar... www.aliexpress.com/item/1005006768029309.html?spm=a2g0o.productlist.main.21.7489zyZpzyZpq5&algo_pvid=9c8238f8-6e27-4510-8a7e-5fac01281b6a&algo_exp_id=9c8238f8-6e27-4510-8a7e-5fac01281b6a-10&pdp_npi=4%40dis%21USD%217.19%215.18%21%21%2152.17%2137.56%21%402167359c17198154480454097eb4e2%2112000039994356366%21sea%21HK%212881401294%21AB&curPageLogUid=boPe8mK5GVRW&utparam-url=scene%3Asearch%7Cquery_from%3A

I try different experiments in each video for the chapter titles, the results are not always ideal. Thank you for the feedback!

let's see how they respond to the first video...

Is that the GISSIO one? To be honest I quite like the nice clear display of the manufacturers UI, but please do let me know what you find out...

@@project-326 I have installed Radpro onto the counter, and I must say that it's much better than the original firmware. It has many more functions. I like how you can change the clicking sounds, and it seems much more accurate. I have a j321 Giger Muller tube and noticed that it is now being affected by my UV light 365nm.

The sample rate (integration time) changes depending on the overall light level. This is a quite common feature of optical spectrometers. From the experiments I have done, it seems to vary from around 100 ms for bright sources to about 2000ms for low-light. I hope that helps!

well, in theory yes, but in practice, probably no. The problem is that this device needs a fairly stable light source for several seconds, so a brief spark wouldn't give a result. I hope that helps!

@@project-326 Thankyou very much.

yes, I am hoping that the manufacturer will be responsive too. What I really like about this unit is the size. It now lives in my work bag on a permanent basis...

Well that's a good few questions... OK, so fluorescent materials are used as scintillation crystals in devices like gamma ray spectrometers, but each type of fluorescent material has different wavelengths that it will be excited by. I would doubt that the materials used for LED production would be useful for gamma rays. Another issue is the number of photons. gamma rays have a LOT more energy per photon, if you had a gamma ray source that emitted the same number of photons as just a small LED, you would basically have a death ray on your hands! Because the number of gamma rays photons is pretty low in the background, gamma ray scintillation crystals need to be connected to detectors that can be sensitive to just single photon events. Radium watch dials, for example, lose their luminosity in a few decades as the fluorescent material crystal structure becomes damaged by years of alpha particle bombardment, and stop glowing. The dangerous thing about that is that the Ra-224 has a half-life of about 1600 years. People often think that dials that no longer glow are no longer radioactive which can lead to some poor decision making in the disposal of the dials. I would assume that there will be a small amount of similar damage by a 450nm blue photon on an LED flourescent coating, but given that the energy of a photon at these wavelengths is about 10^9 times lower, I would assume that the damage would accumulate a billion times more slowly.

I think they chose a mini-USB because it is now just a USB cable, it is the USB-Serial converter and people are less likely to plug in a standard USB cable buy accident. At least that's my conclusion...

@@project-326 I'm not sure to fully understand. usb to serial you normally plug it to a normal usb port on your computer it work with usb-C as well all Arduino like stuffs use that no issue. Now if i have to understand that they use a mini usb plug for a different purpose than usb that is a drama guaranteed recipe as someone will end plugging this in a computer usb plug generating a magic smoke emission.

That's a tough one. All the previous videos on this channel only had 'posh Arthur' as the narrator, this is the first one with a human voice and already some regular viewers are worried that Arthur will be fired. People seem to have a very wide spectrum of opinions on this subject...

That would be a sad loss! 😉

Thank you for the comment. Some of my own thoughts... Each time I use this device, I seem to find a new application. For example, our IR chroma-key video, it was useful for seeing how spectrally pure a commercial green screen actually was (answer, not very). Amateur film makers will find this useful and because of the low cost, photographers can now have a much better tool than the 3 color sensors that are normally used. Anyone involved in pro lighting is also a potential customer. Basic class room education is also opened up, instead of a high school having one $2000 system to share between all classes, there can be more devices available. Anyone involved in the print and finishing industry, QA technicians and product designers. The list just gets longer each time I think about it... This device has earned a valuable place in my work bag, I am really strict about what I carry around but its really useful for far more things than I ever imagined. As for the company, as a tech start-up, their core team are basically scientists and PhD's, so I hope that they can get the help they need with the product marketing going forward.

I hope so too

indeed it can, its one of the few advantages of the PDF report, there is a lot of data printed that shows all kinds of color standards...

@@project-326 ah that's great. Thanks

yes its a surface reflective type...

@@project-326 good! There's hope!

@@jimzielinski946multiple order issues and the fact not much transmits at those wavelengths could damped your hope.

@@peterwoolliams1283 I understand that if they attempt to go into the UV, they have to make sure all the optical components and materials don't absorb UV along the way. I'm thinking about using such a device with microscope illuminators that (they claim) pass UV as short as 250nm. (Some of the quarts lenses I have claim to be rated to 200nm). eBay has been great for finding deals for most of my hobby, though, (working) UV spectrometers are not one of them. Hope is all I have now!!!!

Yes, this type of product is ideal for that kind of application. Lots of spectrometers use cameras as the sensor but they are measuring the position after a diffraction grating, a camera on its own cannot do spectral analysis as it only has three sensors. Imagine measuring a yellow light, the camera will show response on the red and green channels, but it doesn't know if this is a single yellow line or a mixture of red and green. Now translate that across the entire spectrum... I hope that explanation helps

@project-326 Manyvthanks! What if I use a card with colors of known wavelengths, take a photo and check how each color is represented? The yellow under the fake (r+g) light would not look bright yellow but dull, but would look great under a real yellow light.. right?

@@evanc1721 there is no way for a simple 3 color sensor like a camera CMOS device to discriminate, if there was, nobody would buy a spectrometer, it would just be an app on the phone...

That is not an easy answer to give, it depends on the bandwidth of the light source and the area of the beam cross-section. The TLM-2 is rated with a 10-10000 lux range. For example, a 555 nm laser beam (FWHM = 1nm) with 10mm2 of beam cross-section would result in a maximum power of about 1W. If the energy is spread over the typical spectra of sunlight, then the device range will be limited to about 2.196 mW.

Almost everything I own, technically, I don't NEED.

It might sound a bit like that one, but actually its from a different source.

From TaoBao directly?

@@project-326 Yes, taobao official cainiao shipping service. Cost is very low and deliver within 2 weeks for the economics one

@@project-326 Also want to add that I ordered KC761B the same way as well. Works wonderfully too

@@project-326 For some reason youtube keeps deleting my comment..do you have email that I can contact you directly?

Indeed. And I'm incredibly happy KZfaq gained another good channel for informative science

As soon as the product is released, I will let everyone know.

Thank you very much!

@@project-326 you welcome SIR!

I was saving some more info for the 2nde part of the video, but the camera module is actually a monochrome type, according to the manufacturer.

Hey Thanks! I didn't realize that this feature was enabled!!!!

that is definitely a case of creative-fatigue in action...

As I am carrying this device in my small laptop bag, I have realized that 5nm is not ideal but certainly good enough for a lot more applications than I have initially expected. It's quite surprising what you can do with even this limited resolution...

Hopefully the device will be available on Amazon soon...

We cannot determine wavelength, but we can see the difference between a white light with more of less blue, etc. The three white versions of white LEDs tested should show that strongly enough just from the video itself without the spectrometer. Mixing a small number of pure colors will confuse the 'eye' but with a more white spectrum available, we become quite sensitive to color mixes. I always remember the strip light in the kitchen as a kid that had that stark white light verses the filament lights in the other rooms.

These are all really good questions that I hope the manufacturer will be able to have answers too!