BLUblox red and yellow LED lamps (circadian blue free)

[@johnwelbourn3811]

I'm now going to have to go through my entire led collection's light output using a cd interference mirror to check their output spectrum. Fantastic innovation with the cd and a very enjoyable video.

[@cisarvialpando7412]

Yes🔥

[@WagTsX]

that technique of using a CD as a prism is the best part of the video for me, I always wanted to have a spectometer to measure wavelenghts but it's that kind of ultra expensive equipment that you won't use that often, so I ended never buying one. Also I never had too luck using prisms, so this CD mirroring may do the trick easily when needed. I guess this bulbs are just chinese trash but with a posh box to make it look better on the shelf.

[@johnpossum556]

A lot of cameras have histograms which show the light frequencies just like an audio EQ would show the sound frequencies. My Kodak Pixpro 251z does this and its not a very expensive camera. It's ancient, by now you might be able to find a used one somewhere. You might try a pawn shop. Last one I was at had all kinds of digital cameras around the $10 range.

[@TechGorilla1987]

@@johnpossum556 I use something on my iPhone called MoviePro and it also provides histogram features and measurements. Quite strange as I don't fully understand it.

[@johnpossum556]

@@TechGorilla1987 I am not familiar with that piece of sw personally but I did take photography back in what is now called middle school. Back then you would chose your film based on where you were going to shoot. So you basically had 3 common choices. Tungsten rated film, fluorescent film and outdoor film. I believe this is what the camera is doing with the histogram information to give the best possible picture exposure.

[@argcargv]

I wouldn't trust those as the camera has only rgb sensors. So it is at best a very crude approximation of the actual spectrum.

[@Gengh13]

There are some projects of Diy spectrometers that are pretty decent and cheap for hobby use.

[@Langendimi555]

That was a fusible bridge rectifier 🙂

[@WolfGamerBohumin]

Everything is fusible with the right amount of current.

[@stanimir4197]

the IC bp2866 is way more fusible, though.

[@Random_4400]

@@WolfGamerBohumin 🤣🤣🤣

[@HCl_not_HCi]

I like how you showed the light spectrum using the CD. Looks really nice :)

[@MegaSunRise3]

Man that trick with the CD was amazing!

[@BRUXXUS]

The CD spectrum trick was amazing!

[@stanimir4197]

you can use an AM radio (the long or medium) as a make--shift EMF tester.

[@tactileslut]

How many of us still have a pocket radio?

[@SirWolfCZ]

@@tactileslut I think most of us have a portable radio. If nothing else, than because a portable radio is a recommended item in any emergency go bag. You should consider buying one if you don't have any.

[@tactileslut]

​@@SirWolfCZ When last I looked for small radios on the market there were just the two extremes: pricey, like the Grundigs advertised on nationwide syndicated radio at the time, and utter shit like the nonselective nonsensitive FM-only pushbutton interface garbage at the 99.99c store. At prices In between they tended to be larger, sized for a patio table, and have enough computer smarts inside to browse and play Internet radio and to swamp out their own analog receivers with digital noise. I've been physically unstable for long enough that what I remember having and what I can actually find are two very different sets of things. The radio I remember enjoying was a simple all-analog AM/FM model branded Optimus (Radio Shack's better line) with a little speaker but chosen for sounding good while driving headphones from a classical music station's signal that barely reached the store.

[@scratchpad7954]

@@SirWolfCZ Would a shortwave radio work since historically, shortwave has basically been modulated as one huge extension of the AM dial, albeit with upper sideband and lower sideband?

[@prt1527]

Did not know this CD spectrum analyser trick. Really nice !

[@Jeff44]

Nevermind BLUblox light bulb, these should be marketed as bollocks bulbs for their honesty.

[@alexanderbolshakov2747]

The point of using white LEDs and filtering their output is to get light that is more pleasant to our eyes than one of ordinary red or yellow LEDs. There are some videos about this topic on Technology Connections channel.

[@exoticcar5482]

In one way, yes this is true, but at the same time there is some efficiency drops when LEDs are utilized like this

[@RODALCO2007]

Great in-depth research on those Chinese LED lamps. When they state mm instead of nm makes me wonder. The CD trick is awesome, learnt something new today. Thanks for that.

[@peteb2]

Thank you for such an incredibly indepth video on something we are very unlikely to find out the real truth on. I also like your sarcastic witful input & had me laughing like mad through the video. Truly a great YT channel.

[@MichaelGiacomelli]

Interesting that it's actually a Buck converter. Those are getting hard to find in bulbs. Regarding the blue LEDs, it's because the commercially available phosphors are all pumped by blue or UV. Using a direct red or yellow diode would give narrow band illumination, which looks really unnatural, so they're forced to use blue (or UV) pumped phosphor.

[@castlecodersltd]

I really like you add the coloured lines for showing how conventional current lows

[@a.lisnenko]

This CD light spectrum analyzing method! Just WOW! Awesome. Finally, you began to improve poorly made devices and keep them.

[@grumpybollox7949]

CD thing blew my mind

[@mrmeval]

You improved that design greatly. I love the CD trick, that's cool. A good quality stand off phosphor will absorb ALL of the royal blue light LEDs. My employer has a lighting division. Ours would have royal blue LEDs on a massive heat sink with a US designed and built power supply. The phosphor sheet sits a few millimeters off the LED. These are the standard sized theater can lights meant to be certain primary colors so they cannot leak blue and we do send them out to a testing service for performance and safety certification. We did make an A19 style white 'bulb'. You cannot cheaply fit a good system in those bulbs. I'd suggest mixing up a thermal epoxy, a high temperature epoxy with a good alumina filler and packing it in. You won't be repairing it afterwards, but you won't see the thermal degradation those have in a few months. I have two of those. They are almost 7 years old and work just fine. They have an elaborate reflective system over the standoff phosphor that looks cool. To manufacture it we could not get the cost below $30 which meant it would need to sell for around $50 due to regulatory and industry compliance. But it let the newly minted engineers feel loved and the design advances went in our other products.

[@fadeout007]

I found you so knowledgeable, today I learned how to check the spectrum of LEDs using a CD. TNX😄

[@jp040759]

Very clever use of CDs for light spectrum visualization. Great job as always.

[@richardturton6900]

I have tried sleeping with a red light and do find it restful. The problem is that I keep getting disturbed by old men in shabby raincoats knocking on my front door and asking about French lessons.

[@RocRizzo]

🤣😂🤣😂

[@EJEuth]

Very interesting this discussion about real RedLED driven x RedPhosphorusBlueLED driven. Another food for thought is how WIDE the RedPhosphorus would be, compared with an almost monochromatic RED led. And I liked you showing the practical use of a CD as a “poor man” spectrometer. Thanks!

[@Miata822]

Good video. Glad that you teach new things. Using a CD for diffraction was new to me. I really look forward to the car headlight video. Why do car lights not use high frequency?

[@elvinhaak]

Have you seen the taillights of many cars or the breaking lights of a moving car with LEDs? They give a strobing-effect because they are in a relatively high frequency but the car is moving faster so you see red-dots/red-stripes instead of one continues line as with tungsten bulbs. If you would use this in headlights that illuminate the road and other traffic over a big distance, you would get very distubring strobing-effects unless at really high frequencies and that would be very dangerous for the traffic. So they make it (almost) continues instead of pulsed. Actually you would have a bit of doppler-effect like with sounds in some directions but with reflections combined with this. Actually some cars have this effect as defects or when someone build some diy lights on them like lights that should only be used as working-lamps not as driving-lights. At least here in the EU forbidden to use in traffic for good safety reasons.

[@SilvaD702]

Typical cheap leds in a fancy box

[@Electester]

Those bulbs are scam AF… No EMF… yyyyyeaah… I had a bulb with similar circuitry with no isolation… and the noise emission was huge! It’s enough to say it’s not legit (I mean trustworthy) product when you see millimeters instead of nanometers - good and reputable companies don’t do mistakes like this. Good video! Greetings!

[@westelaudio943]

I had an Osram bulb with "traaaansformeeer" in it... Made horrible noise as well and failed early... I thought it was a flyback running in burst mode all the time for some reason. Maybe it was a buck regulated one like this though. I don't remember, or didn't pay attention to how the ferrite device was connected on the PCB.

[@Speeder84XL]

Interesting. The amount of blue light in the yellow one, was pretty much expected when looking at the spec (typical blue lasers are about 450 nm and those look really "deep" blue and any shorter than that and it goes more towards violet - so 470 is indeed very blue. Green lasers are typically 520 or 532 nm as comparison). The reason they use phosphor LEDs and not red LEDs is probably because the phosphor ones still give out a relatively wide spectrum of light (even if most of it is in the red part of the visible spectrum). "True" red LEDs gives almost monochromatic red light (which means all color perception is lost - everything will just be varying intensities of red. With the phosphor ones, you will still see some colors - even if everything still look reddish).

[@AmigaA-or2hj]

A very warm white light bulb of 1800k works just as well. The red bulb reminds me of a fireglow filament bulb.

[@bluerizlagirl]

Inductors work as though they contained very heavy electrons, which cannot just suddenly stop or start moving; but must accelerate slowly from rest when a voltage is first applied, and take some time to slow down when it is removed.

[@jls2975]

12:20 the chargers cemetery 🤭

[@stevecoatesdotnet]

The 'Low EMF' statement will satisfy those who are 'electrosensitive'. As electrosensitivity doesn't really exist, it doesn't really matter if the statement is true or not :).

[@luich1288]

minute 12:16. if there was a fusible resistor probably it would not blew the bridge, a good example of how this lamp can start a fire if something fails

[@ivanlubis1171]

I want to request content to unpack/diassembly/tear down the philips smart wi-fi 9w and philips hue ... Thank you

[@uiopuiop3472]

This was pretty interesting. For those wanting more info on white LEDs and how they became mass produced, check out the "How Blue LEDs Were Invented - LGR Tech Tales" mini-documentary on YT

[@JohnnyX50]

I have Smart Bulbs in the room I sleep in, I change 1 to low red and the other off, I sleep like a baby in dim red light :)

[@Mark1024MAK]

But babies are known for waking up every couple of hours and crying…!!!

[@zaprodk]

Oh wow i'm looking forward to teardown of that LED headlight!

[@Voldees]

i guess those LEDs are Samsung LM302N series or some very similiar from other brand. it has lower blue spike because those two blue chips produces different wavelengths so there is actually same amount of blue, but it does not makes such a big visible spike on spectrometer on same wavelength.

[@artursmihelsons415]

That PCB has manufacturers marking "Dark Energy".. 😂

[@wolfdale_3m]

Great packaging for not-so-great products

[@pirelli77]

Hi, i also saw this coil in the controller of the escooter. I was surprised because they don't actually have any. Is this now a back regulator that picks up the reverse current that flows back from the Motor? Then I don't have to install Diodes as many recommend. you know what i mean, it's about conductive load from the mototr back to the electronics, which flows back as high voltage when switch it off

[@tkordus]

There is place for fusable resistor fr1. You could measure power at 85V

[@robertgaines-tulsa]

I'm sure they are trying to avoid monochromatic light by using phosphors with blue LEDs.

They can use PC Amber chip, or use monochromatic LEDs of different wavelenght. For example I have LED which has 3 different chips - 595nm, 605nm, 630nm. It produces nice orange light and it is not unpleasent monochromatic light.

[@JeanPaulElectronics]

@ I believe it's colour rendering must be very poor. It's better idea to use a bit broad band white light mixed with monochromatic light.

@@JeanPaulElectronics You can distinguish between colours quite easily. Since it is an orange light it is somewhat different compared to white light with low CRI. It doesnt feel bad at all. Or you can just use PCAmber - for me it is the best technology for light at night. CRI is usually around 50, which sound low, but it is actually good for that purpose.

[@DigitalBhangari]

Dvd added to my equipment

[@j7ndominica051]

The issue with blue light is way overblown. Tungsten lamps also had a small intensity of blue in their output to see colors, and nobody complained. Putting a filter in front of the LEDs dramatically reduces their efficiency. These could be used as a festive decoration. But for this case I'd prefer more saturated monochromatic LEDs.

[@mortlet5180]

It is also, obviously, not even flicker free. You can even see the interaction between the light's flickering and the camera's frame rate at the start of the video! (around 4:27)

[@DiodeGoneWild]

This one has virtually no flicker. You wouldn't be able to see the flicker anyway because my camera ran at 50 fps.

[@Delali]

Your videos are really detailed and hella interesting to watch. Keep up the good work.

[@anonymoususer6448]

haha... sleepy cat saying: "He's too lazy to...." Look who's talking :-) nice one !

[@DoctorCalabria]

Amazing CD trick! Thanks

[@williama29]

wait why is there a FCC logo on a product from Europe at 1:51 ?

[@glmnet]

full bridge rectifier gone wild

[@Enderkruemel]

The Chip is a Bright Power one, ( Standard one )

[@jendak7921]

Is there reason for connect transformer before measured equipment instead of osciloskop? Transformer must be designed for high current in some case not just few watts for osciloskop

[@12villages]

I can't tell you how many times I've shorted power transistors and blew them up while probing them with my multimeter.

[@klave8511]

Those blue lights can be very disturbing … especially if they’re flashing …. behind you when you’re driving along minding your own business

[@TechGorilla1987]

I think it would be fun if you did a video in your native language and provide CC for us as well. I would enjoy listening to that.

[@twocvbloke]

I built myself a "yellow light" a few years back, it looks more like a low-pressure sodium streetlight though, which is nice, but it's quite bright, probably cos I put a lot of 1 watt LEDs in it... :P

[@superdau]

LEDs with an actual red chip (non-phosphor) would look "too red" and very unnatural, because of the narrow color band. Think brake-light-red. Not something that you'd like to light a room with (unless it's part of a disco/rave setup ;) ) [EDIT] should have watched the next video as well. But I like to watch them in order ;)

[@adamkekow6558]

11:40 maybe it is called stroboscopic effect?

[@TheSpotify95]

Hmm, I thought they were actually designed for use in festoon lighting strings (like the mains outdoor lights with large bulbs on them), rather than actually in home use...

[@TheSpotify95]

Yeah, I don't get why they used blue LEDs even though they claimed to not have blue. Were they relying on the plastic cover filters? The only thing I see these as any use for is festoon lighting strings; for anything else (such as general household illumination) it is better to just get white LEDs in your preferred color temperature (e.g. warm white, daylight, etc).

[@levetbyck]

3:02 Can’t the blue/cyan light be caused by the tint of the cd disk.. - ok, nvm (just excited to see the usage of the cd)

[@stanimir4197]

of course not - the color won't change as it depends on the wave length. If the photons with such wave length were not present in the 1st place, it'd not be visible at all.

[@levetbyck]

@@stanimir4197it’s fine, I get it. It was just the first thought that came to me when I saw the trick Great channel btw.. following it in and off (trying to catch anything that makes sense)

[@elvinhaak]

Now I want to use such a red lamp to see if it does do bad things in a darkroom on photopaper. Do you have it and show such a test? If the blue really gets filtered out well it should not do anything on the paper so you can use it while printing photo's (yes, the 'old-fashioned way' with negatives and such)

[@DiodeGoneWild]

for a dark room, I'd only trust real red LEDs.

[@elvinhaak]

@@DiodeGoneWild Probably, but on the other hand, all tungsten darkroom-lights had a bulb with a color-layer or fixture with a filterlayer around it. Actually I have tried real red LED's pure too and they did make an effect on the paper.

[@ledhunters]

Do the headlight, do the hedalight :) It should have some nice Osram led-s inside :D

[@Tigrou7777]

10:15 you say that "when the transistor is turned on, the current goes linearly through the current sensing resistor". Why is it linear? I would expect it to be non-linear, as it is when you measure the current in a simple RL circuit.

[@k4be.]

The current through an inductor increases proportionally with time when it's connected to a constant voltage. In reality this is limited by the inductor saturation (it would start to rise more steeply if the driver allows that, which it shouldn't). The voltage is not actually constant, but it's close enough.

[@daveamerion8177]

It is not linear, but if you consider time as a fraction of a time constant (L/R), the curve can be considered linear.

[@michaelturner4457]

Maybe using yellow LEDs instead of white LEDs with the yellow filter would make it too monochromatic?

[@Ni5ei]

There are 590nm pure yellow LEDs readily available... That's cheaper than producing the "yellow" bulb as it is.

[@TheEmbeddedHobbyist]

Bs en iec 62031:2020 has a lot of requirements on led lamps, if you have 206 euros to spare and want some good bed time reading ;-)

[@rabihnasr7228]

Thank you

[@princebanini]

Interesting stuff

[@Evgen-Evgen-Evgen]

12:21 And if you open like 100 power supplies.. OMG)) I laugh out loud))

[@Basement-Science]

I think in general anything other than blue LEDs is very bad in terms of efficiency. Also, for lighting you always want at least a somewhat wide spectrum of light, even if it is red. A phosphor-less LED has a very narrow spectrum so you couldn't tell any colors at all in the room. With this red-orange spectrum you should see much better.

[@DiodeGoneWild]

Blue LEDs are the most efficient by energy conversion, but not by luminous efficiency (because human eyes see blue as dim). You're right, a wider spectrum looks pleasant. But maybe combining red, orange and yellow LEDs would work too....

[@Mark1024MAK]

So explain how a RGB LED display (and I don’t mean a LED backlight for a LCD) can produce vivid bright displays even when the blue LED is not lit…

[@Basement-Science]

@@Mark1024MAK Those are not built to light up a room. Any type of light-emitting display can function with much lower brightness than you need for that. Plus, modern Green LEDs are pretty close to blue in terms of efficiency, and in general you can use (red) phosphor based LEDs in an RGB display anyway. Or you can run the red LEDs at a higher current/power to get the same brightness.

[@Basement-Science]

@@DiodeGoneWild I'm sure you could make a halfway acceptable yellow spectrum (peaky like a CCFL) with phosphor-less LEDs, but it would almost certainly be very inefficient and much more expensive at a decent brightness. All the efficient yellow or orange LEDs are probably phosphor-based blue as well. The circuitry for driving multiple types at once at different currents would also be more complex even ignoring the higher power consumption (different currents for different colors).

[@Mark1024MAK]

@@Basement-Science - But if you want to light up a room, you really need white light, as the human eye is most sensitive to white light. That’s why all general purpose lighting is white. And why, to us, a white LED appears brighter than a traditional LED (which of course has a fairly narrow frequency bandwidth of light). Even though white LEDs actually use blue LED technology (and the blue light is also a narrow band)… Anyway, as said elsewhere in these comments, this misconception that blue light causes sleeping problems is the only reason that these lamps (featured in this video) are being marketed like they are. A fool and his/her money are easily separated. It would be interesting to see how much these cost compared to RGB/multicoloured mood lighting lamps.

[@TESLA_KF507]

A nebo si prostě rozsvítím obyčejnou žárovku. :-)

[@DiodeGoneWild]

Já taky radši žárovku. To spektrum těchhle spánkovejch LEDek je až moc nepřirozený. U žárovky jde ještě víc ubrat modrou snížením napětí, třeba triakovkou.

[@jamesvandamme7786]

I've seen those and they never tell you how much actual light you get out of them. The efficiency must be terrible.

[@someone2506]

wow.. That's the cheapest built LED bulb i ever seen... The driver is just wrapped in transformer tape and left to dangle smh.. Hipster tech - shit product in a fancy box, add some health or environmental bs story - boom! Slap a 500% price on it and start selling to the sheeps... S-M-H every time.. Anyway - good vid and amazing trick (light spectrum) 😎

[@Purple431]

A poor man's spectro-graph

[@bgyuri1985]

and now teardown that oscilloscope :D

[@ogdan1173]

Hello Glados from portal2.

[@midinotes]

Great suggestion using the CD for observing the light spectrum. Which artists though are the best for this? Any particular genre of music? I’m guessing blue jazz is more likely to enhance the UV end of the spectrum. Made me laugh though your analogy of using blue LEDs to produce light without any blue in it! Classic!

[@vaclavtrpisovsky]

I laughed seeing that the color is noted on the obviously colored bulb... Who needs it? A colorblind person who bought it for developing photos?

[@WagTsX]

not even colorblind people couldn't see a color that obvious, it's only some shady shades that are confused for us colorblinds, not vibrant colors. Sorry for ranting, but I really hate when people do this kind of dirt joke without really knowing what's it.

[@vaclavtrpisovsky]

@@WagTsX Yeah, I was joking, I know that neither protanomalia nor deuteranomalia don’t affect vision im most of the spectrum, and the red plastic is obviously darker anyway. I assumed this was common knowledge and everyone would get it as a joke, didn’t mean to be offensive... just thinking about the edge cases that may have been the reason for the marking.

[@WagTsX]

@@vaclavtrpisovsky true, maybe the marketing was as obvious as when you buy an oven that have a warning stating that it becomes hot when in use.

[@jobik6462]

Dobrej podovod 🤣

[@4zims]

do true yellow LED exist?

[@Pyromonkey360]

yes also ciano and magenta but they have gotten hard to fingor very expensive for some reason

[@4zims]

@@Pyromonkey360 thanks

[@Basement-Science]

yes, but they are very inefficient. They're only good as indicators, pretty much.

[@Mark1024MAK]

@@Basement-Science - they are nowhere near as efficient as ‘white’ LEDs, true. But good quality ones are better than you are implying. Especially if you connect a lot in series in the same place.

[@Basement-Science]

@@Mark1024MAK connecting LEDs in series has no effect on their efficiency.. Also, 'good' ones are most likely just blue LEDs with phosphor as well.

[@iamrap9]

Please make a video about how to make a DIY watt meter.

[@michaelblack5011]

how N Chanel Mosfet transistor is switching when current senses resistor is connected two the GND and is only 1.8 ohms and Sours it connected two the GND ? GND -----| R 1.8 ohm |---- Sours ?

[@stanimir4197]

the source is connected to the resistor, not to the ground 9:23. The voltage drop across the resistor is compared to some internal reference, and if it's too high - the transistor is switched off.

[@michaelblack5011]

@@stanimir4197 Resistor is connected to GND what volt drop with 1.8 ohm ?? Sours is connected the resistor ! then Sours where is connected , when resistor i connected to GND ? how is switched off when Source always is connected to GND ?

[@stanimir4197]

@@michaelblack5011 "when Source always is connected to GND", there is 1.8ohm resistor in between. Look at the schematics again.

[@michaelblack5011]

@@stanimir4197 that's exactly what they said ! where is connected the resistor ? Source ---| SMD Resistor 1.8 ohm |--- GND Gate ----| |---- 400v 4.7 mf , Drane ---|>--- Led 54 V

[@stanimir4197]

@@michaelblack5011 7:34 pin 1-gnd (see the trace below DB1, it's the ground), pin 5-source connected to the smd (smd connected to the same trace), 7-8 - drain

[@loreskewan928]

😘😘😘😘😘😘😘

[@jawjuk]

"Roooooooooox-anne..."

[@Jako1987]

So they used more money on the nice packaging than the bulb itself...

[@intel386DX]

This is orange, not red

[@fredflintstone1]

A great use for all my old CDs🙂

[@shaileshchityala2787]

meanwell SMPS LRS SERIES

[@Bobit53]

Good lamps, but maby expensive. And little dagerous without fuse.

[@ashutoshkc]

M from India 🇮🇳

[@cmuller1441]

In x1 the probe has a lot less bandwidth so he's just filtering out the high frequency noise.

[@marka1986]

If you want yellow light cheaper to buy a bug light.

[@zaprodk]

LOL What a scam. I love your example of using meat to make vegan food :D

[@willrobbinson1]

just a another dodgy product re light output as for safety fuse the bridge did a good job as i guess they tested a sample and declared the bridge would open without fire? dodgy , even the claim light op is dodgy

[@jmr]

A new level of crap. I'm hearing that while eliminating blue light is helpful it's overated anyway. Kinda of like switching from regular coffee to half caff then drinking a whole pot.

[@jmr]

@Sara Michael Ashraf Because they just took regular led light bulbs and covered them with filters. It would have been better to produce the intended color in the first place. It's more efficient and you get more of a pure spectrum.

[@jmr]

@Sara Michael Ashraf I try to use warm white light bulbs that have less blue and I use the "night light" function on my phone. If you want to go further you could look for blue blocking glasses. EDIT:. It definitely helps to also use less light in the evening!

[@jmr]

@Sara Michael Ashraf You could get RGB smart bulbs and set them to the color you want.

[@jmr]

@Sara Michael Ashraf I'm sure there are good specialty bulbs out there too.

[@jmr]

@Sara Michael Ashraf Yes the warm white will have some blue. I don't think you will like lights white absolutely no blue in them. I think you should look for an RGB or RGBWW smart bulb that lets you dial in the various colors. I use those in my most used lights. They let you dial in the various colors based on your needs. You can use full spectrum in the day and remove blue in the evening.

[@stanley9h1lo]

This rubbish is being let onto the market (allowed since has CE mark apparently) is killing the amateur radio hobby with extreme interference to sensitive radio receivers and the authorities just don't care less and do nothing about them as it's a "free open market"

[@dcocz3908]

Blue when advertised as no blue just seems like another Fake Chinese product

[@ReallifeBambiDeerattheFarm1]

So these lamps are filled with lies. Typical.

[@publicmail2]

Being lied to by some china company, big surprise.

[@electronicayciencia]

CD as a diffraction grating is cool. To get a clearer spectrum you can use a far light source (spot light) or pass the light through a slim slit or hole. Also, if you wish to get better color separation use a DVD instead of a CD. To have the angle more manageable, cut a piece of the CD. I did some experiments and calculations in the past in my blog (spanish): www.electronicayciencia.com/2010/07/espectroscopia-casera-con-dvd.html www.electronicayciencia.com/2010/07/difraccion-en-un-dvd.html

[@piconano]

You can build a nice spectrometer and free analysis software from spectralworkbench.org I built one 4-5 years ago for about $5 and it still works. I use it to identify fake UV LEDs.