News Raspberry Pi Project Sanitizes Masks with UV Light

Giroro

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Jan 22, 2015
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UV-C light definitely has proven sanitation properties, it is also quite dangerous and totally invisible. You can get a radiation burn (sunburn) off of a UV-C lamp in a couple minutes, but thankfully it doesn't penetrate most glass or transparent plastic. UV-C lamps need to be made out of a special quartz glass that the light can pass though.

The near-UV purple light put out by common "UV" leds might make florescent paint shine with that blacklight glow, but it's not so effective at toasting germ DNA.
UV-C leds are rare, exotic, expensive, and emit no visible light. They also are not really more efficient or cost effective than using an older florescent tube lamp. Those gas-filled UV-C lamps will emit a blue glow as a byproduct of producing UV-C, but LEDs do not have this byproduct. If a "sanitizing UV" LED is producing a blue or purple light, then it is fake and ineffective at sanitation (even if it makes blacklight sensitive colors glow).

Now the Box of hope webpage is a bad mobile site with no technical information, so I have absolutely no idea what kind of kind of LED hardware they sourced for this student project. Just be aware of the limitations of UV-C before buying/building a fake germicidal product. There is a huge amount of scammy snakeoil and fake garbage on the market, especially since the pandemic. It's best to just steer clear of the led products entirely right now, and stick with the florescent tubes.
 

carocuore

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Jan 24, 2021
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UV-C light definitely has proven sanitation properties, it is also quite dangerous and totally invisible. You can get a radiation burn (sunburn) off of a UV-C lamp in a couple minutes, but thankfully it doesn't penetrate most glass or transparent plastic. UV-C lamps need to be made out of a special quartz glass that the light can pass though.

The near-UV purple light put out by common "UV" leds might make florescent paint shine with that blacklight glow, but it's not so effective at toasting germ DNA.
UV-C leds are rare, exotic, expensive, and emit no visible light. They also are not really more efficient or cost effective than using an older florescent tube lamp. Those gas-filled UV-C lamps will emit a blue glow as a byproduct of producing UV-C, but LEDs do not have this byproduct. If a "sanitizing UV" LED is producing a blue or purple light, then it is fake and ineffective at sanitation (even if it makes blacklight sensitive colors glow).

Now the Box of hope webpage is a bad mobile site with no technical information, so I have absolutely no idea what kind of kind of LED hardware they sourced for this student project. Just be aware of the limitations of UV-C before buying/building a fake germicidal product. There is a huge amount of scammy snakeoil and fake garbage on the market, especially since the pandemic. It's best to just steer clear of the led products entirely right now, and stick with the florescent tubes.
So most of the "UV Lamps" you can find on sites like ebay or amazon are just fake regular blue/violet lamps? for example there's a "Philips UV-C Disinfection Desk Lamp [Energy Class A+]" lamp listed at about $130 on amazon but the only picture is just a stock photo with the lamp emitting a dim blue-ish light and looks made out of cheap plastic not quartz.

There's a lot of crap going on around sanitising surfaces, masks or whatever, I've got a free kit from city authority and it came with a mask that's said to be infused with special copper ions and "nano layers", and a spray that feels like regular alcohol, smells like regular alcohol and probably tastes as regular alcohol too yet its label says "does not contain alcohol".
I just stay home as long as possible and only go out to get food and basic items.
 
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Giroro

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Jan 22, 2015
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So most of the "UV Lamps" you can find on sites like ebay or amazon are just fake regular blue/violet lamps? for example there's a "Philips UV-C Disinfection Desk Lamp [Energy Class A+]" lamp listed at about $130 on amazon but the only picture is just a stock photo with the lamp emitting a dim blue-ish light and looks made out of cheap plastic not quartz.
The lamp that came up when I looked that up seems legitimate to me. It has two glass tubes in the middle with incandescent filaments which should get the tubes going. They also added safety measures to turn it off when people are around. Fake lamps don't bother with safety, because they aren't actually emitting the dangerous light.
Blue light is expected from UV-C tubes like that, it is an unintended byproduct though. You can't control the light emitted by a fluorescent tube that tightly, so a lot of the light will be the wavelength you want, but some of it won't. In the case of these UV-C lamps, that color is dull blue.

When a fake LED sanitizer has blue LEDS, they're added to emulate that effect and trick people into thinking the device is working like a real lamp. People are starting to get a little wise to that tell-tale blue glow, which is why some sellers switched to blue instead of "blacklight" purple.
But LEDs have a very narrow wavelength of light that they can emit. A blue LED will only emit blue light, and a UV-C led will only emit invisible UV-C.
Although, I've seen some industrial UV led arrays that mix in a small number of blue LEDs with the real ones. I think they do that so that people can tell when they're on. Looking directly at a UV-C LED is very bad, even though there is no visible light. That's the kind of thing they would build into a water filter though, not a magic wand on Amazon or eBay.
 

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