UVC Sanitizer Box - mostly fake

PhotonWrangler

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I bought a couple of "UVC Sanitizer Box" devices recently out of curiosity to see if the LEDs might be useful for other projects. This is a white plastic tub with a door that's marketed as something for sanitizing your cellphone, keys or other small objects. Put your phone inside, close the door and push the button to "sanitize" it in 5 minutes.

The photos on the carton show an array of bluish LEDs running along both sides of the tub and imply that the device bathes your cellphone in UVC light.

Upon close inspection I found that all of the LEDs look the same except for one larger metal encased one on the left side. The others are smaller ones with white plastic cases. Hmm.

I unboxed a second unit and found the same thing. This wasn't a manufacturing fluke; they intended to have one LED that's somehow different from the rest of them. Could it be that only one of the LEDs is actually UVC and the rest are fake?

It turns out that this is indeed the case. I used a UVC-detecting phosphor indicator and confirmed that this sanitizer contains exactly ONE actual UVC LED, and the rest are regular blue LEDs whose wavelength was carefully chosen to resemble the same visible color that's emitted by the actual UVC LED. This means that if you put your cellphone in thiis unit, it will only sanitize the upper left corner of the phone! The rest is just Covid sanitization theater.

I wanted to give everyone a heads-up on this so you don't wind up fake-sanitizing your phones or other devicves. The SKU on the bottom of the carton is 7498603211,, Item # 03211 from TV Direct LLC, sold in the DIY chain that rhymes with petards for around $10.
 

KITROBASKIN

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From wikipedia:

"Hoist with his own petard" is a phrase from a speech in William Shakespeare's play Hamlet that has become proverbial. The phrase's meaning is literally that a bomb-maker is blown up ("hoist" off the ground) by his own bomb (a "petard" is a small explosive device), and indicates an ironic reversal, or poetic justice.









 

PhotonWrangler

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Thanks Kitrobaskin. I couldn't think of another two syllable word that rhymed as well. No hidden meaning intended for the store chain!

**Edit**
Ok, it also rhymes with Bernard's. I'll use this going forward.
 
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KITROBASKIN

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PW, your posts are always appreciated.
Having heard the 'hoist petard' phrase in the past, I thought petard might be trousers or underwear or something.

Would you consider that the inside of these sanitizer boxes might somehow reflect the UVC emissions, thereby exposing more of the object to the waves?
 

PhotonWrangler

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Thank you for your kind words, Kitrobaskin.

The inside of the box is white plastic. I will conduct an experiment to look at reflections and post my findings here.
 

Dave_H

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I bought a couple of "UVC Sanitizer Box" devices recently out of curiosity to see if the LEDs might be useful for other projects. This is a white plastic tub with a door that's marketed as something for sanitizing your cellphone, keys or other small objects. Put your phone inside, close the door and push the button to "sanitize" it in 5 minutes.

The photos on the carton show an array of bluish LEDs running along both sides of the tub and imply that the device bathes your cellphone in UVC light.

Upon close inspection I found that all of the LEDs look the same except for one larger metal encased one on the left side. The others are smaller ones with white plastic cases. Hmm.

Good piece of detective work...thanks. I noticed these products in a number of stores generally in the range of $25-$40 or more but was suspicious by the lack of meaningful specs on the packaging, and some dubious claims.

Based on reading about UV-C LEDs they have very low efficiency for a number of reasons, no doubt cost a lot more than regular visible LEDs, and not likely to find a whole bunch of them in a low-cost consumer product.

BTW which phosphor(s) work for UV-C versus near-UV? I imagine some specific minerals would work, if you have them.

Digressing a bit, there are line-powered LED near-UV bulbs out there claiming germicidal properties but rather vague on that, and not claiming COVID specifically, which we know near-UV is not good for. One is even "dual-mode" with regular visible light, with one vague warning about eye exposure. Lots of opportunistic products to be wary of.

Dave
 

badtziscool

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I'm pretty sure we all had the feeling this was the case. Nonetheless, thank you for confirming our suspicions PhotonWrangler.
 

PhotonWrangler

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Update -

It looks like the single UVC LED is a dual wavelength UVC/UVA unit with two separate emitters in it, one for UVC and the other for UVA. The other LEDs in the unit appear to be just UVA, which can kill some bacteria but cannot deactivate Covid or other viruses. I have not identified the UVA part yet.

The UVC led appears to be a "3535 UVC UVA" part. The link includes a photo of the sanitizer box in question.
[h=1][/h].
 

snakebite

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however the safe and healthy uvc wand does emit plenty of uvc.
it will erase eproms in 2 power cycles.
roughly the same time my g15t8 takes to consistently pass a blank check.
 

PhotonWrangler

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Erasing eproms... gosh that takes me back. I used to use a g15T8 tube to wipe eproms in about 20 minutes. That was before they had the improved glass bulbs that blocked the ozone-generating wavelength.
 

Dave_H

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I've just picked up a wand-style UV LED disinfectant device cheap at a second-hand store. It parallels description of the box-style earlier described: 18 of 20 SMT LEDs have white body and appear to give off near-UV. Two have gold-tinted bodies, hard to tell how much far-UV they put out but not much; these have distinctly purple (v. violet) visible glow.

Product brand is Medic Therapeutics.

Unit seems to work but not useful to me for disinfection. It uses 18650 with USB charger and makes my day-glo posters light up, not brightly, but OK for about $4.

Dave
 

PhotonWrangler

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I've just picked up a wand-style UV LED disinfectant device cheap at a second-hand store. It parallels description of the box-style earlier described: 18 of 20 SMT LEDs have white body and appear to give off near-UV. Two have gold-tinted bodies, hard to tell how much far-UV they put out but not much; these have distinctly purple (v. violet) visible glow.

Product brand is Medic Therapeutics.

Unit seems to work but not useful to me for disinfection. It uses 18650 with USB charger and makes my day-glo posters light up, not brightly, but OK for about $4.

Dave
The ones with gold bodies could be UVC. See if they can fluoresce some postage stamps, which might contai n UVC activated phosphors.

The white-bodies UVA or near-UVA leds might be able to kill certain types of bacteria but not viruses, so it's not an entire loss in terms of "sterilizing," however in the current context most are looking for devices that can kill (deactivate) viruses.
 

Dave_H

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The ones with gold bodies could be UVC. See if they can fluoresce some postage stamps, which might contai n UVC activated phosphors.

The white-bodies UVA or near-UVA leds might be able to kill certain types of bacteria but not viruses, so it's not an entire loss in terms of "sterilizing," however in the current context most are looking for devices that can kill (deactivate) viruses.
Good on both points. Gold SMT LEDs resemble dual UVA/C 3535 part by Dongguan Uchi Elec. "35UVA+UVC06-003" but can't be sure.

"Stamp test" seems less conclusive. Patterns on current Canadian stamps are not visible under normal light but show up dimly with UVA flashlight and this wand light. Under strong UVC (mercury tube w/filter), patterns are visible, also border lights up yellow-green. UVC from LEDs must be fairly weak but wand having been used may have some impact. List price of the wand is US$75 plus taxes and shipping.

Dave
 

PhotonWrangler

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Back in the days of air mail stamps, the USPS used a UVC reactive phosphor coating on these stamps and a different coating on regular surface mail stamps so the sorting machines could differentiate them and route them accordingly. I believe that the continued use of UVC reactive phosphors is probably mostly an anti counterfeiting measure now. They're still handy for detectming the presence of UVC.
 

Dave_H

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I recently spotted a small handheld UV LED "disinfection" light in a Canadian chain store for only $10. Part of me thinks that if/when feeling like buying one, I should lie down until the feeling goes away. OTOH, perhaps they will go on sale for half-price, happens fairly often with this store. At least it might be a good UVA-mostly light.

In the same store I saw a very small tube-type UVC light running on 4AA. Cost was $13 but was the last one and didn't bite, interesting though.

Dave
 

Dave_H

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This one is the real deal. I picked it up for $50 at the DIY chain that rhymes with Bernards and confirmed the UVC output with my phosphor detector card.
The small handheld sanitizer wand at the store which rhymes with "petards" or "Bernards" looks similar to the one I picked up which uses a UVC tube (by appearance of the image). SKU #3460672.

Dave
 

PhotonWrangler

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I bought one of those UVC tube-based sanitizers at the "M" store and it was DOA. I just set it aside for now. One of these days I'll try to isolate whether it's the HV power supply or the tube. This is why I'm happy to see progress on UVC LED development.
 

Dave_H

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I bought one of those UVC tube-based sanitizers at the "M" store and it was DOA. I just set it aside for now. One of these days I'll try to isolate whether it's the HV power supply or the tube. This is why I'm happy to see progress on UVC LED development.
I've already had mine apart to look at the HV supply, small power transformer; no measurements though.

Mine does not operate unless pointed downwards, at first thought it was NF, could that be your problem?

Dave
 
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