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Thread: Coronavirus flashlight

  1. #1

    Exclamation Coronavirus flashlight

    Hi all, first post here.

    In need your help...
    to create a UVC LED flashlight for disinfection purposes eg. bacterial, viral etc.

    I found this UVC 4xLED:
    https://www.aliexpress.com/item/4000...archweb201603_
    I want to use the above PCB and make my own flashlight, by either:

    1. Buy a host and relevant accessories or
    2. Buy a ready-made flashlight and swap the PCB


    From the information on the page I can see:

    1. LEDs cover a 7.5x7.5 mm area which should be considered
    2. PCB is a 20x20mm area which should be considered
    3. 2x 18650 should be enough based on voltage requirements.


    I have not done a flashlight from scratch before (just upgraded my maglight to 3xLEDs).

    I need some guidance from the experts in here.

    Thank you in advance

  2. #2
    Flashaholic* KITROBASKIN's Avatar
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    Default Re: Coronavirus flashlight

    Are you going to name your flashlight Coronavirus? How does your post relate to a sickness? Cleaning surfaces will not guarantee contracting this disease, right?

  3. #3

    Default Re: Coronavirus flashlight

    Quote Originally Posted by KITROBASKIN View Post
    Are you going to name your flashlight Coronavirus? How does your post relate to a sickness? Cleaning surfaces will not guarantee contracting this disease, right?
    I am not interested in selling or naming the flashlight. I just want to make some for my family and friends asap. Plus it may be useful for everyone else.

  4. #4
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    Default Re: Coronavirus flashlight

    You can do some searches with the Google bar at the top regarding disinfecting with a flashlight. It has been brought up a number of times. But as I recall itís unlikely you can generate enough power to make such a thing effective.

  5. #5

    Default Re: Coronavirus flashlight

    Quote Originally Posted by nbp View Post
    You can do some searches with the Google bar at the top regarding disinfecting with a flashlight. It has been brought up a number of times. But as I recall itís unlikely you can generate enough power to make such a thing effective.
    Thanks for the tip - I will have a look.
    As to the effectiveness, you could also try a search for medical studies. Some have shown that 2500uJ/cm2 can easily destroy any living microbe in under 15s from a distance of 2-3 cm.
    So I am sure it will be effective the closer you get it and the longer you have it running.
    No worries.
    Also bear in mind that there already exist commercial UVC LED offerings out there, but most are gimmicks with just 1 LED for more than $30! The serious offerings are over $100 and they are all quite effective at a 2-3cm distance with the only difference being the time it takes to neutralize the hazard.

    What I really need is some pointers towards either a source for host flashlights which can take this 20mm pcb and can take 2x 18650 or other appropriate battery.
    I have already contacted xtremegadget.com mtnelectronics.com fasttech.com flashaholics.co.uk but they could not provide any help in fitting this pcb into an appropriate host.
    I need the help of an experience builder who can look at the PCB and suggest to me an appropriate host based on his experience of what hosts he has seen out there.
    I can easily take it from there.

  6. #6
    RCS1300's Avatar
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    Default Re: Coronavirus flashlight

    The UV wavelengths needed to disinfect are typically not available to the public. You will not find these emitters online.

    UV-C wavelength of between 200 and 300 nm kills or inactivates micro organisms by destroying their nucleic acids and disrupting their DNA. Whether this will be effective against a particular virus would have to be tested. (If it were effective against this new virus you would have seen or heard about it already).

    I will see if I can find you an article that describes the different wavelengths and their purposes.

    Edit add:

    https://materion.com/resource-center...erms-with-leds

    "In particular, the wavelength of 264 nm is incredibly impressive at killing germs, viruses and bacteria."
    Last edited by RCS1300; 02-20-2020 at 03:29 PM. Reason: Clarity

  7. #7

    Default Re: Coronavirus flashlight

    Oh, before I forget, the MAJOR reason I want this thing is for MASK DISINFECTION.
    Masks are very expensive. We cannot be throwing them away after a few minutes of wearing them.
    With this flashlight we could just pass it over the outer surface of the mask and it will be safe to use again for at least a few more times.
    In my opinion it is well worth it for the money you will be saving.
    Of course you could buy one of those portable UVC lamps, but you cannot beat the portability of a flashlight, plus it is better for those who hate ozone.

  8. #8

    Default Re: Coronavirus flashlight

    The 275nm is PERFECT and the PCB I posted is 275nm. I am well aware of all the UVC capabilities already in the public domain.

  9. #9
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    Default Re: Coronavirus flashlight

    Quote Originally Posted by RCS1300 View Post
    The UV wavelengths needed to disinfect are typically not available to the public. You will not find these emitters online.

    UV-C wavelength of between 200 and 300 nm kills or inactivates micro organisms by destroying their nucleic acids and disrupting their DNA. Viruses do not have DNA as a virus is not a biological. I do not believe a UV-C light will work against a virus.

    I will see if I can find you an article that describes the different wavelengths and their purposes.
    Viruses are actually DNA strands wrapped in a protein coat so UV can destroy them but whether a flashlight can offer sufficient destructive power I am not sure. When I worked in the lab for a contract packager years ago our RO water system had UV capabilities but the water ran past multiple large UV lamps wired into the system. I donít know the specs but they were pretty powerful. Personally, I suspect use of a proven cold sterilant would be a cheaper and more effective way to disinfect hard surfaces. It is not however, a more FUN way to disinfect.

  10. #10
    RCS1300's Avatar
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    Default Re: Coronavirus flashlight

    Quote Originally Posted by nbp View Post
    Viruses are actually DNA strands wrapped in a protein coat so UV can destroy them but whether a flashlight can offer sufficient destructive power I am not sure. When I worked in the lab for a contract packager years ago our RO water system had UV capabilities but the water ran past multiple large UV lamps wired into the system. I donít know the specs but they were pretty powerful. Personally, I suspect use of a proven cold sterilant would be a cheaper and more effective way to disinfect hard surfaces. It is not however, a more FUN way to disinfect.

    Thank you for that.

    https://sciencing.com/virus-dna-4058.html

    The OP is not going to get his hands on a LED emitter that will have the proper wavelength. If he could, it would have to be exhaustively tested against the particular targeted virus. Duration and intensity of exposure would be variables tested.
    Last edited by RCS1300; 02-20-2020 at 03:24 PM.

  11. #11

    Default Re: Coronavirus flashlight

    I will agree with you on the fun part for sure! I love building stuff myself.
    But please keep in mind that UVC lamps in water filtration systems have a very small window of time to kill whatever passes in their vicinity.
    This build is different. We have ample time to disinfect small items.

    Most manufacturers have 90s timers built into similar offerings.
    If in doubt, go over your item for 2 minutes at close distance. That should do it.

  12. #12

    Default Re: Coronavirus flashlight

    Guys, 275nm kills everything. All you need is 2500uJ/cm2 for 15s. I have done enough research to be confident in this.
    Therefore 2500uJ/cm2 for 90s from 2-3 cm is more than enough to kill anything inside the pores of your mask for example.
    275nm is very pervasive - it will even penetrate your skin and even give you skin cancer. Very dangerous stuff. It will work.

  13. #13

    Default Re: Coronavirus flashlight

    I cannot provide a link guys (as per CPF policy), but you could do a search for a company called 59s and have a look at their products.
    You will see the LEDs we are talking about.
    e.g. they have a wand product with 20 LEDs and some sterilizing containers.

    All I want is a host for this 20mm pcb which can supply 6+ volts and a controller which has only on/off.
    That's it! Please give me some directions.

  14. #14
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    Default Coronavirus flashlight

    Iím not that good at building lights so I cannot offer a lot there but my background is in biology and working in a lab where we made OTC drug products for skin care so the nerdy science part of this is fun for me and thatís the angle I am trying to help with here.

    In any case, whatever you do end up building, it is critical that you send it out to an accredited lab with microbiological testing capabilities to have the device fully validated before you use it to sterilize medical devices of any kind. Otherwise it may be as effective as a spoon is at sterilizing and you wonít know it, leaving you in the most dangerous possible situation: believing something is safe when it is not. Much of the cost of the commercially built solutions will be the cost of properly validating the device in labs to do exactly what it says it does given a particular usage case. Since your device will be home built, you will need to have this done to be certain it works in the way in which you intend to use it. Then and only then should you trust it with your safety!

  15. #15

    Default Re: Coronavirus flashlight

    Quote Originally Posted by nbp View Post
    Iím not that good at building lights so I cannot offer a lot there but my background is in biology and working in a lab where we made OTC drug products for skin care so the nerdy science part of this is fun for me and thatís the angle I am trying to help with here.

    In any case, whatever you do end up building, it is critical that you send it out to an accredited lab with microbiological testing capabilities to have the device fully validated before you use it to sterilize medical devices of any kind. Otherwise it may be as effective as a spoon is at sterilizing and you wonít know it, leaving you in the most dangerous possible situation: believing something is safe when it is not. Much of the cost of the commercially built solutions will be the cost of properly validating the device in labs to do exactly what it says it does given a particular usage case. Since your device will be home built, you will need to have this done to be certain it works in the way in which you intend to use it. Then and only then should you trust it with your safety!
    You are absolutely right. Nothing worse than a false sense of security.
    Safety should be the top priority here.

  16. #16
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    Default Re: Coronavirus flashlight

    For a variety of reasons, what you are describing is unlikely to be effective and/or safe.

    Without getting into the weeds of the discussion, I agree with @nbp that for your stated intended purpose(s) a "home-made" hobbyist-type project would be inappropriate.
    ... is the archimedes peak

  17. #17

    Default Re: Coronavirus flashlight

    You may be right there.
    Of course, even the commercial products mentioned earlier, could suddenly decide to malfunction, thus leaving you with a 'false sense of security' as NBP already mentioned.
    Even so, that does not mean that we have to give up.

    I myself also do not want to get into a deep discussion into medical and health safety issues, but I will provide the following points for you to consider.
    1. In case of a pandemic, when you are having difficulty obtaining masks (plus costing an arm & leg), you will be forced to disinfect what you have. I will remind you that recently we were shipping masks to China because they run out! Can you believe this?
    2. It is better to have a solution rather than none at all.
    3. You should not have only one solution. Always have a backup. Masks are built to BLOCK most everything. So how do you disinfect the pores? Ozone could be a second option, but it has to travel into each pore. I am not certain it can be done. Radiation will most certainly do the trick. (using liquids probably will not work and actually may help to either deform, moisten or block the mask, lowering its effectiveness or even rendering it useless - in an emergency you could run alcohol through it, but that is just wasteful IMHO)

    Keep this in mind.

    UPDATE:
    Yes, for most consumer masks like N95, N99, P100, FFP3 etc, ozone will have no problem penetrating and passing through it. This is because 'MOST' of these masks have no active filtering for ozone and other gases (usually requires activated carbon to absorb these). Even a HEPA filter or other type of mechanical filter will have no effect on ozone levelsóthis includes the filter that might be built into your HVAC system. Therefore, yes, you can use ozone as a secondary layer of disinfection of you masks, keys, shoes, wallets, money.... you get the point.

    So come on builders - help me build this thing!
    Last edited by conandrum; 02-20-2020 at 06:01 PM.

  18. #18
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    Default Re: Coronavirus flashlight

    What kind of masks are we actually talking about? If they are plastic full face shields then this is easy, cold sterilants will definitely be the way to go. Disposable surgical masks are porous and absorbant and not ever meant to be reused. Furthermore their ability to effectively block tiny viruses is debated anyways. To penetrate the fibers enough to denature microbes buried deep inside I think you will need a powerful light source and a considerable exposure time. In this case I still think submerging them in an FDA approved disinfectant solution and air drying and storing them in a sterilized environment would be the easiest and cheapest and probably most effective way to go.

    Then use your soldering skillz to build some sweet flashlights with long runtimes to keep you rocking through the power shortage parts of the virapocalypse!!!

  19. #19

    Default Re: Coronavirus flashlight

    LOL you cracked me up!!

    Hey guys, let's not get wrapped up in the usecases here. You could sterilize anything... money, wallets, keys, etc. you can have in in your car, back pocket, purse.
    Come on, suggest to me a suitable host for this 20mm PCB and a suitable controller and let the build begin. ))

  20. #20

    Default Re: Coronavirus flashlight

    Can anyone suggest a suitable host for 6+V that can take a 20mm PCB?
    Thanks.

  21. #21
    Flashaholic* DIWdiver's Avatar
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    Default Re: Coronavirus flashlight

    I'd bet you could mod a Convoy L2 to take that emitter with a little effort (the center hole in the reflector needs to be opened up). I don't have personal experience with this host, so maybe someone who does can chime in?

  22. #22

    Default Re: Coronavirus flashlight

    Hey, Thanks for the suggestion.
    I can see that this flashlight can take 2x 26650 @3.7V, but it can also take only one.
    That opens the question: what voltage is it sending to the LEDs? Does that depend on the controller?
    What controller should I use with these UVC LEDs which need 6+V to operate properly? and ideally I need only ON/OFF functionality because there is probably NO VISIBLE LIGHT in order for you to adjust the power. So it is better to have just ON/OFF functionality.

  23. #23
    Flashaholic* DIWdiver's Avatar
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    Default Re: Coronavirus flashlight

    The L2 has two sections of tube. If you use both, you can fit two batteries in series. That would give you 6-8V. There's no way, in that host, to get two batteries in parallel for 3-4V. That's the voltage sent to the driver. The driver determines what gets sent to the LEDs.

    Almost all LED drivers are either current regulating (meaning that they control the current sent to the LEDs) or direct drive. A direct drive or FET driver simply connects the battery to the LEDs with as little in between as possible. These drivers depend on the resistance of the batteries, LEDs, FET, and wiring to limit the current to a safe level.

    The LED board you linked to is designed for only 80 mA, so you definitely want a current-regulating driver. A FET or direct drive driver would probably fry the emitters in a second or less on fully charged batteries, even low-current ones.

    80 mA is a pretty low current for flashlight drivers. While there are many that can be dimmed to that level, or even well below that, you'd want to make sure it NEVER came on at full power. There are few drivers that have a max of less than 350 mA, and that could easily destroy the emitters before you knew something was wrong. There are some however, that have a resistor that can be changed to adjust the max output current.

    I usually make my own drivers, so I don't follow the commercial world very well. If there's a good driver out there for you, I'm not aware of it. What you need is a low dropout buck or linear driver with a sense resistor you can change to adjust the output current. Maybe someone will suggest a good one for you. Usually people are interested in changing resistors to increase output, but you want to decrease it, but that shouldn't matter.

    I actually have made and sold such a driver, and while I haven't sold one in some years now, I could easily make you one with a single 80 mA mode. It's rather spendy and massively overkill for what you want, and I'm not sure it would fit in the L2, but if so I think it would actually work pretty well. Post in this thread if you are interested. https://www.candlepowerforums.com/vb...-and-Improved!

  24. #24

    Default Re: Coronavirus flashlight

    Thanks DIWdiver. To be honest its much better if we can find off the shelf, cheap parts otherwise its not worth the effort.

    I ask the moderator to allow this link due to necessity.
    Take a look at this: https://www.aliexpress.com/item/4000...c00XiPsey&mp=1

    They show a driver powered by USB. (I also send messages to 3 similar listings to tell me what 20mm driver they suggest with their PCB)
    The displayed driver is square though, but it seems to be designed to power even 3x LEDs (maybe even 4x - I will wait for their reply).
    Do you think we can use this square driver inside an existing host? Maybe an existing host which has openings for USB charging?

  25. #25

    Default Re: Coronavirus flashlight

    What about those fluorescent disinfectant lights, you could leave them running in an empty room for several minutes pointed at the thing you're trying to disinfect.

    Big Clive had one where it would fit into a regular household light fitting.

  26. #26
    Flashaholic
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    Default Re: Coronavirus flashlight

    I bought a few of the Rayvio xp series UV-C leds for the same reasons. They are specifically made for medical applications: http://www.rayvio.com/wp-content/uploads/2017/05/DS04-RayVio-XP-Datasheet.pdf

    https://www.digikey.com/en/product-h...ies-uv-emitter

  27. #27

    Default Re: Coronavirus flashlight

    254nm, anything higher is not effective, you also do not want that light to hit your skin, there are germicidal fluorescent bulbs sold, that have enough power and aren't mad expensive

  28. #28
    Flashaholic* RUSH FAN's Avatar
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    Default Re: Coronavirus flashlight

    Interesting thread.
    Not sure if the OP created the thread as mental folly, or is duly serious.

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