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(Coronavirus) On UV Sanitization
- Thread starter AudubonB
- Start date
I guess one could also test it on plants. I think I'll test it on a weed in the yard.
Plants & Ultraviolet Light
I built a UV-C box a few weeks ago. I used two old cabinets I had and put them together. I am putting everything that comes into the house through it. I have a bulb on the lid and one on the floor, a baking cooling tray for setting the items on. I ran power for the lights through the box into a power strip with a switch on the outside. The box is lined with aluminum foil. There are two handles on the lid, one we labeled "contaminated" and the other as "clean".
I am using two GE 11077 - G8T5 Germicidal Fluorescent Light Bulbs ($11 each) and two GE Slimline 14in. Fluorescent Light Fixtures ($15 each). My next step is to add a fail-safe electromagnet on the lid so it is locked when the power is on. We've opened it a few times with the lights on, which can't be good for us.
The hardest part of this project was not the build. It was figuring out how long I need to zap items in the box to kill viruses. I have it calculated now with the help of a friend who is an Electrical Engineer. Aluminum foil reflects 80% of the light with each bounce so it has about a 4X magnification of light for the areas directly exposed to the bulbs and probably 2X for the sides. In my box, I calculate it takes only about 10 seconds to kill viruses. We keep stuff in there for 90 seconds just in case.
If anyone is interested in build plans or my spreadsheet to calculate exposure, let me know. This has been a fun project. I have learned a lot and it is now a lot easier to deal with groceries than wiping them down.
I am using two GE 11077 - G8T5 Germicidal Fluorescent Light Bulbs ($11 each) and two GE Slimline 14in. Fluorescent Light Fixtures ($15 each). My next step is to add a fail-safe electromagnet on the lid so it is locked when the power is on. We've opened it a few times with the lights on, which can't be good for us.
The hardest part of this project was not the build. It was figuring out how long I need to zap items in the box to kill viruses. I have it calculated now with the help of a friend who is an Electrical Engineer. Aluminum foil reflects 80% of the light with each bounce so it has about a 4X magnification of light for the areas directly exposed to the bulbs and probably 2X for the sides. In my box, I calculate it takes only about 10 seconds to kill viruses. We keep stuff in there for 90 seconds just in case.
If anyone is interested in build plans or my spreadsheet to calculate exposure, let me know. This has been a fun project. I have learned a lot and it is now a lot easier to deal with groceries than wiping them down.
This is false. Please provide your source. I bet if you read it closely, you'd see this isn't their recommendation.
It is pretty dangerous and you don't want to be exposed to it. UV-C light breaks down DNA and RNA in viruses, bacteria and in you. If you use it, you want it in a sealed chamber so no light leaks out.
Ozone hole three times the size of Greenland opens over the North Pole | Live Science
Nature now providing UV-C around the north pole. Time to move to Alaska!
BTW, so the ozone created by the UV-C bulbs would actually block UV-C... so I guess after leaving the light on for some time, the box will fill with ozone, meaning reduced potency from light but increased potency from ozone (pollutant for indoor air but it is also a cleaner).
Nature now providing UV-C around the north pole. Time to move to Alaska!
BTW, so the ozone created by the UV-C bulbs would actually block UV-C... so I guess after leaving the light on for some time, the box will fill with ozone, meaning reduced potency from light but increased potency from ozone (pollutant for indoor air but it is also a cleaner).
Yup, and how dangerous depends on how strong the source is, how far you are from it, and how long you are exposed to it. Think of it as a fire - the larger (and hotter) the fire, the closer you are, and the longer you are exposed, the more damage. UVC in the right dosage can cause burns on the skin and temporary to permanent eye damage, and that dosage threshold is nowhere near as high as it is for UVA/UVB (or sunlight, for that matter).
Yep, I'm worried about that. So hard to identify the counterfeits. I see cards from reptile shops that will verify UVB but nothing simple for UVC. I watched the above video on using glow beads to verify but without a known good UVC source, I'm still in the dark. I guess I could take a few blood agar plates from the lab home and see if I can sterilize them?
N5329K
Active Member
Robin
Maybe throw some insects in there? Let us know how you test it. I'd like to try something too.
Careful—I think that is how the Cockroach That Ate Cincinnati came to being!
linux-works
Active Member
just realized that the company that makes the UV sensor that many of us are using, also makes one for uv-c!
GUVC-S10GD Genicom Co., Ltd. | Sensors, Transducers | DigiKey
from the data sheet it seems to be identical to the UVA one that everyone has on their breakout boards, except its more 254nm focused. same diode voltage, same interface, etc.
I ordered a few of those and some of the more expensive uvc sensors.
looking at ebay and amazon, the real uvc test gear starts at $500 and I'm just not willing to throw that kind of money on an amateur non-proft project like this.
(would be cool if there was a way to have a group-buy for some shared access to a meter like that. on eevblog, which I check from time to time, the calibration guys have a similar thing where one bit of calibrated test gear is mailed around for local 'transfer standards' use. you calibrate your local ref, then mail the test meter to the next guy on the list. no idea how that would work for an expensive bit of kit, but maybe it can be done somehow.
I do think that we should create a useful (does not have to be to lab standards) uv-c meter that has some link to a real one that has NIST certs. its not hard or expensive other than getting access to a good meter, for one calibration test run.
GUVC-S10GD Genicom Co., Ltd. | Sensors, Transducers | DigiKey
from the data sheet it seems to be identical to the UVA one that everyone has on their breakout boards, except its more 254nm focused. same diode voltage, same interface, etc.
I ordered a few of those and some of the more expensive uvc sensors.
looking at ebay and amazon, the real uvc test gear starts at $500 and I'm just not willing to throw that kind of money on an amateur non-proft project like this.
(would be cool if there was a way to have a group-buy for some shared access to a meter like that. on eevblog, which I check from time to time, the calibration guys have a similar thing where one bit of calibrated test gear is mailed around for local 'transfer standards' use. you calibrate your local ref, then mail the test meter to the next guy on the list. no idea how that would work for an expensive bit of kit, but maybe it can be done somehow.
I do think that we should create a useful (does not have to be to lab standards) uv-c meter that has some link to a real one that has NIST certs. its not hard or expensive other than getting access to a good meter, for one calibration test run.
I agree. Buy bulbs that publish their specs. GE does this for their germicidal bulbs like this one. https://consumer.gelighting.com/catalog/p/11077
linux-works
Active Member
damn. these may all be fakes, for all we know.
Buyer Beware: This LED Bulb Sold As Germicidal Doesn’t Emit UV-C
I bought one; going to try returning it to amazon. it was not 'prime' and so I expect lots of push-back from the seller, but I paid a lot for this and if its useless, I'm not going to just eat the cost.
sigh.
from now on, I'll just stick to the tubes; but even then, if they don't use quartz glass, then its also mostly useless. no idea how faked this field is, but I expect it to get worse, not better, for the short term. the appeal of selling fakes to scared people is appealing to many 'bad actors' out there ;(
Buyer Beware: This LED Bulb Sold As Germicidal Doesn’t Emit UV-C
I bought one; going to try returning it to amazon. it was not 'prime' and so I expect lots of push-back from the seller, but I paid a lot for this and if its useless, I'm not going to just eat the cost.
sigh.
from now on, I'll just stick to the tubes; but even then, if they don't use quartz glass, then its also mostly useless. no idea how faked this field is, but I expect it to get worse, not better, for the short term. the appeal of selling fakes to scared people is appealing to many 'bad actors' out there ;(
linux-works
Active Member
this seems to be a vendor who makes specialized test gear and has actual uvc meters:
Solarmeter® Model 8.0-RP UVC Meter With Remote Probe
and sensors
Ultraviolet Germicidal Irradiation (UVGI) for accurate dose measurements
still quite expensive for the meters. no idea what the sensors cost.
my order with digikey went thru and I should get some sample uvc diodes in a week or so. my plan is to swap out the uva sensor from the adafruit or generic breakout board and put this one in, from the same company. I'll be able to use my setup with 2 sensors; one will be the uva and the other will be uvc. in theory, I should be able to get a rough idea if the bands are 'good' for not, for this use. I don't care as much (right now) about absolute accuracy, just getting the right sensor so I can verify fake bulbs, etc.
I'm thinking a side industry (non profit) should happen, just to make affordable and trustable uvc meters or at least detectors. people should be able to verify if they have a real uvc bulb or not. this is serious; we need to know if our disinfection boxes will work or not. this is not the TSA and there's no tolerance for security theater, here; we need bulbs that work and we need to be able to prove that or know that, for sure.
Solarmeter® Model 8.0-RP UVC Meter With Remote Probe
and sensors
Ultraviolet Germicidal Irradiation (UVGI) for accurate dose measurements
still quite expensive for the meters. no idea what the sensors cost.
my order with digikey went thru and I should get some sample uvc diodes in a week or so. my plan is to swap out the uva sensor from the adafruit or generic breakout board and put this one in, from the same company. I'll be able to use my setup with 2 sensors; one will be the uva and the other will be uvc. in theory, I should be able to get a rough idea if the bands are 'good' for not, for this use. I don't care as much (right now) about absolute accuracy, just getting the right sensor so I can verify fake bulbs, etc.
I'm thinking a side industry (non profit) should happen, just to make affordable and trustable uvc meters or at least detectors. people should be able to verify if they have a real uvc bulb or not. this is serious; we need to know if our disinfection boxes will work or not. this is not the TSA and there's no tolerance for security theater, here; we need bulbs that work and we need to be able to prove that or know that, for sure.
linux-works
Active Member
linux-works
Active Member
some good news: I got a quick refund from the seller, for the led 'uvc' corncob light.
I bought mine pretty early on and it was $100 for the lamp and remote/base.
the seller did not give instructions on the lamp's return. he did not ask me any questions or put up a fight. and that's pretty unusual. wonder what this means.
perhaps this is going to be a scandal in china? this item sold big, from what I could tell, and if they are all fake (not uvc, as promised) then its a big deal. if people bought these and ended up taking chances they should not have, due to trusting that these were doing their actual job, that's pretty big news. lots of low level sellers (like mine) who bought from someone who maybe had a level up from him. but I do think that once word gets out and amazon cancels them all, users are going to want refunds and the whole thing is going to backfire.
maybe the goal, all along, was just to get 'use' of our money for a while? who knows.
the more I read about this issue on hackaday, the more I'm thinking that it can't be possible to put this many real uvc leds on there for this price. and that uvc leds still just aren't strong enough to make sense, here.
I bought mine pretty early on and it was $100 for the lamp and remote/base.
the seller did not give instructions on the lamp's return. he did not ask me any questions or put up a fight. and that's pretty unusual. wonder what this means.
perhaps this is going to be a scandal in china? this item sold big, from what I could tell, and if they are all fake (not uvc, as promised) then its a big deal. if people bought these and ended up taking chances they should not have, due to trusting that these were doing their actual job, that's pretty big news. lots of low level sellers (like mine) who bought from someone who maybe had a level up from him. but I do think that once word gets out and amazon cancels them all, users are going to want refunds and the whole thing is going to backfire.
maybe the goal, all along, was just to get 'use' of our money for a while? who knows.
the more I read about this issue on hackaday, the more I'm thinking that it can't be possible to put this many real uvc leds on there for this price. and that uvc leds still just aren't strong enough to make sense, here.
