Using devious techniques to test UV lights.

Maybe it isn't up to you to prove that Mary's product is fake.. It's being sold with alleged health benefits, perhaps she should be providing formal lab results that prove her lamp does indeed produce light with germicidal properties. She could get dues otherwise...

Gordo

This was a great video. I'd have been interested in seeing what your purple laser did to the readings (probably nothing but LAZERZZ).

It depends on the type of glass. I'd need a wide spectrum meter to test that.

Big Clive

It may be worth waiting for the novelty to wear off and the price may drop if they have excess stock.

Big Clive

Glass also blocks UV-B does it not?

Mike Page

As fake as they may be, these blue LEDs they are using make nice lamps for those that like color associated with UVC tubes. For that I may snag one. My 36W UVC lamp came in the other day and I've been using it around the house and it is now sitting in the car on a timer to try to get rid of some odor. I was surprised it made the trip from China to Florida in one piece. I was even more surprised to see it completely encapsulated in Styrofoam. I am pleased. https://youtu.be/yeDdMsrKG2w

AESFTW

I got my 60W (30W) Ice-blue LED light yesterday. Note that it seems to use a buck regulator so the solder pads should be treated as being live.

Big Clive

The sensor should give a good indication of UV blocking effectiveness.

Big Clive

Hell yeah, shout out to Lady Ada.

Jeremy Impson

Thanks Clive ! I am very grateful for your attention to this subject. I have bought some of the UVc LED corn cob lights as well. I have tested mine in several different ways. Your right they are just blue LEDs. They claim 60 watts but they draw 30 watts from the mains. They produce no ozone as advertised they do. As we know , no LED can get down to the 185nm anyway. I have tested these LEDs next to the Hg vapor that are doped with Ti and also the ones that are not which are producing the ozone. I'm trying to get a video put together that shows these tests. Hope I can share that soon. Thanks again Clive.

Jeff Larson

I’m just saying, for devil’s advocate purposes, someone who is prepped to not believe Clive would also then not believe his hand written graph.

Can you get a third party somehow to verify the whole glass blocks uvc thing? You show the paper in the beginning which convinces me but a detractor might just call that phooey and then refer to your less than impartial attitude and dismiss your science entirely. But if you could show a screenshot or something of the same graph from a textbook or online source then it would due further solidify your findings Clive!

Perfectly convincing to a rational person. In our meme laden TikToc era of short attention spans the Marys of the world would have clicked away before you finished explaining the chart. Imaginary death rays attract more attention than real ones.

Bill Kerr

I think that this test is fairly conclusive. They are selling fake UV lamps, and I suspect they know damn well that they are fake, because as you say the meter for testing the UVc is very expensive and they know that Joe Bloggs isn't going to even bother checking if it's real. Good for you for calling them out.

Mike Hughes

That could be a fast test.

Big Clive

I got my bright blue not fake at all LED lamp from eBay today too. The 195 ice-blue LEDs fail to please the UV sensor and are referenced directly to the mains via what I guess is a buck regulator inside.

Big Clive

Could this be used to test the efficacy of AliExpress sunglasses?

Adam Baxter

I think a lot of eBay sellers (& people in general) are probably unaware of the various UV wavelengths, they're just copy pasting details. They may even believe they are selling the real thing?

Wim

Looks good, though I’d also love to see the simple science version of it with a packet of yeast put in two dishes of sugar water. Expose half to a real UVC and half to the disco light. I expect the difference would be fairly visible as one activates and one just dies.

The Griffiths Family

My job used to be presenting research results to corporate management, who were the ones to decide if we got funding to do more! So I think about things from a technical communication angle a lot :-)

PeteyPak

Great video!! I wondered if you might find some clever way to attack this! _*If*_ you're trying to make a point to the crazy brigade (don't know if you care), an offset of about 12mV, to zero-out the base level, could be really nice. Say if you're making any extra or separate recordings for Mary. If the meter shows a value but the point is that a light isn't doing anything, crazies or contraries will jump on that. "It's not zero, look! You're lying!". These are the folks who won't follow what you're doing, or what "that measuring device" (multimeter) is, and doubtful they'll be sufficiently numerate to understand how to interpret a constant offset in a set of readings. And they'll be a pain in the arse about it. But even a well-intentioned general intelligent-but-non-technical audience might misinterpret what they're seeing if they're not experienced with making and interpreting measurements. 95% of us Big Clive fans probably are, but 95% of the general population aren't. I'd probably mention that there's a measuring artefact, cancel it out, and then continue with that offset out-of-sight-out-of-mind. Measurements where fake or blocked lights literally show zero in the numbers on screen, are more compelling.

PeteyPak

That's a good test!

Nani Isobel

Great video. There seem to be paper test strips for UVC too http://intellego-technologies.com/hospital/

Great job Clive. You'd make a great attourney! Verdict for the prosecutor!

Michael Paige

I think you proved it just fine. I see that Geni-uv also makes a GUVC-S10GD Photodiode that is UV-C and has a range of 220-280nm but you’d have to build up a circuit board. http://www.geni-uv.com/download/products/GUVC-S10GD.pdf

Jeff LaHay

i just got my totally authentic not fake at all UVC LED light for $30 from china today! its a slightly different attempt of fakery than your disco light i took some pictures https://imgur.com/a/JitSHk1

2:03 AM AS I WRIGHT THIS at least you found some free disco lights

God 420

Was just going to ask the exact same thing lol. Bet there'd be even more waffle back from Mary

John Carr

I suppose you now need to give Mary the bad news..... I Hope they have a good corporate lawyer! ;-)

Nocturnal.... Me too!

It seems like a valid test to me. Certainly more authentic than their purple germicidal lights.

Mark Trombley

Yeah. Very nocturnal.

Big Clive

Isn't it like 4:30 AM where you live, clive? You are really nocturnal.

Basti Elektronik