# What flashlight can survive EMP?



## MROD (Dec 16, 2008)

Hi, I am new to this forum, been reading lots of reviews and finding deals on flash lights. 

I had a question, I have 2 LED flash lights, both CREE and I was wondering, will these flash lights or any other for that matter be able to survive an EMP blast?

I have read lots of stuff lately about different terror tactics and thought, if the lights are out that could possibly mean that the circuit boards on these lights would be fried.
:shrug:


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## Flying Turtle (Dec 16, 2008)

*Re: What flashlight can survive...?*

Welcome to CPF, MROD. This has been discussed before. If you put EMP in the Google Search at the top of the page you'll get some links. Seems like no one knew for sure.

Geoff


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## StarHalo (Dec 16, 2008)

From the last "When EMP Attacks" thread:



StarHalo said:


> We've covered this topic before (it just _sounds_ like a CPF topic, doesn't it) and it turns out that it would be possible for a hypothetical ICBM-armed enemy to do an EMP-specific attack: Setting off a warhead ~120 miles above Los Angeles, for example, would be sufficient to blackout not just the West Coast, but *everything west of the Rockies*, with no blast, heat, or (nuclear) radiation damage at all.
> 
> The catch is the aforementioned ICBM - only the countries that can afford the most advanced defense systems have them, so this technique isn't possible for "terrorists" (who are more likely to use a dirty bomb) or even the North Koreans (would use a standard blast nuclear attack), though China could do it.
> 
> If you're truly distressed by remote possibility of an EMP attack, or you just want to try a fun project, you can build your own EMP-proof box. Just grab any container (Pelican case, cigar box, even a cardboard box) and some copper screening (available at your local crafts store) - coat the entire exterior of the container with the copper screening, ensuring the screening touches at the seams/openings and there's no bare spots. That's it. Place a small radio tuned to a strong local station inside the box, and if all it receives is static when the box is closed, it works - you now have a fully EMP-proof utility box. :thumbsup:


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## Timothybil (Dec 16, 2008)

If the flashlight is totally metal, including the reflector, it's basically a 50/50 tossup. On one hand, the metal housing of the flashlight acts as a 'Faraday Cage', just as described in the previous post. This should ensure no damage to any electronics embedded in the flashlight. On the other hand, there will probably be some 'skin effect' where while the metal housing shunts the EMP pulse around the enclosed space, the pulse will induce some eddy current in the housing that will result in a small em field along the interior surface. How far out from the interior surface and how strong the current would be are subject to speculation. On the gripping hand (always wanted to use that line) the only concrete data we have on the effects of an EMP pulse come from the days of tubes and discrete transistors, with lots of point to point wiring and almost no PCBs. This type of structure provides orders of magnitude greater antenna area for the pulse to induce current in than today's architecture of very small PCBs with very short and small traces. Again, no concrete data exists.

My personal opinion is that a totally metallic light placed inside a Faraday Cage such as the previous poster described should survive intact. That would be a pain because it would mean that after a pulse attack, one would be required to go to the location of the safe box to obtain a workable flashlight. One idea would be to take a holster like the BCC I use and line it with the aforementioned copper mest, including an attached flap to be attached to the holster flap and thus close the end. While not a 100% cage, it would come very close and should be effective, especially if carried bezel down. In the interest of preventing cosmetic damage to the light, the holster could be provided with an interior cloth pouch that would come between the light and the copper screen. It would be an interesting experiment if one could find a large pulse generator.


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## Igor Porto (Dec 16, 2008)

Build or buy a big metal box/safe to store spare computers, flashlights, watches (solar powered), batteries, radios and anything you'd like to survive through an EMP blast.

Talk about paranoia.


I would do it... :thinking:


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## boosterboy (Dec 17, 2008)

If Indianna Jones can survive a nuclear explosion while hiding inside a refrigerator, then my flashlights can too right?:nana:


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## Guy's Dropper (Dec 17, 2008)

Doesn't an emp-proof box have to be grounded?


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## brucec (Dec 17, 2008)

I would think any metal safe (jewelry or gun safe) would provide plenty of protection from an EMP. A microwave oven would probably be pretty good too. I would also think most metal flashlights would be fine just on their own, especially the ones that use the whole flashlight body + head + tailcap as ground (non-anodized threads).


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## LukeA (Dec 17, 2008)

Igor Porto said:


> Build or buy a big metal box/safe to store spare computers, flashlights, watches (solar powered), batteries, radios and anything you'd like to survive through an EMP blast.
> 
> Talk about paranoia.
> 
> ...



I would use a mechanical watch.


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## Timothybil (Dec 17, 2008)

Guy's Dropper said:


> Doesn't an emp-proof box have to be grounded?


Grounding would greatly improve its function, but the main idea is to create a space that the emp pulse is guided *around* and not allowed through. 

A corollary function of a Faraday Cage is to not allow any electromagnetic waves _*out*_ of the confines of the box. Here it definitely is a requirement for the cage to be grounded. If you have ever had any contact with Top Secret data or information processes, you have probably been in a Faraday room (Cage), even if you weren't aware of it.


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## Mdinana (Dec 17, 2008)

I always though that if a device was "off" then an EMP didn't affect it ... ?


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## NightTime (Dec 17, 2008)

Mdinana said:


> I always though that if a device was "off" then an EMP didn't affect it ... ?


 
I think that even if the device is off, there would be enough current (induced by the blast) to turn it "ON" and OFF at about the same time!


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## Stereodude (Dec 17, 2008)

This topic has been hashed to death before here and here.

Also there's some more discussion here and here.


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## brucec (Dec 17, 2008)

Timothybil said:


> If you have ever had any contact with Top Secret data or information processes, you have probably been in a Faraday room (Cage), even if you weren't aware of it.



My company has one. No cell phone coverage in there.


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## mchlwise (Dec 17, 2008)

brucec said:


> I would think any metal safe (jewelry or gun safe) would provide plenty of protection from an EMP. A microwave oven would probably be pretty good too. I would also think most metal flashlights would be fine just on their own, especially the ones that use the whole flashlight body + head + tailcap as ground (non-anodized threads).




I've got an ammo case that I got from the surplus store where I keep some extra flashlights and batteries. It was about $8 bucks, and is waterproof, airtight, and pretty close to being a Faraday cage. 

Like everyone's said, nobody KNOWS for sure what will happen, and there are good arguments either way. I think the only one who makes any claim is Peter Gransee, when he said that the Arc-AAA SHOULD survive an EMP. 

I have some "emergency lights" in my cars, which I have wrapped with aluminum foil, just in case.

I think most lights should be fine, but better safe than sorry as far as I'm concerned.


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## FlashCrazy (Dec 17, 2008)

Timothybil said:


> If the flashlight is totally metal, including the reflector, it's basically a 50/50 tossup.


 
If my wife questions me again about having so many flashlights, I'll just point her here. "See honey, the more I have, the better our chances of some of them surviving an EMP attack."


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## StarHalo (Dec 17, 2008)

As noted previously, you can test the EMP-proofness of any container by tuning a small radio to the strongest local station you can find, then placing it in the container - if all it receives is static, then that container is 100% EMP-proof.



brucec said:


> A microwave oven would probably be pretty good too.



Very true, a microwave is _required_ to be completely EMP-proof.


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## clg0159 (Dec 17, 2008)

So then we all have *nothing* to worry about, we just need to start storing our torches in the microwave.


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## Stereodude (Dec 17, 2008)

clg0159 said:


> So then we all have *nothing* to worry about, we just need to start storing our torches in the microwave.


Can you come over and explain that to my wife?


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## kelmo (Dec 17, 2008)

Any flashlight outside the blast zone(s) will survive. Head for the hills. 

If I know someone is dropping the nuclear hammer I will make a necklace out of all of my lamp assemblies, grab a six pack and sit on my roof. When my necklace flashes I'll slam my last beer!!!

It'll be glorious man!!!


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## wacbzz (Dec 17, 2008)

brucec said:


> My company has one. No cell phone coverage in there.



I've been inside a DuPont building with the same thing taking place. No walkie-talkies either.



Stereodude said:


> Can you come over and explain that to my wife?



I didn't think I could laugh any harder after I read this ^ 

Until I read this:



kelmo said:


> Any flashlight outside the blast zone(s) will survive. Head for the hills.
> 
> If I know someone is dropping the nuclear hammer I will make a necklace out of all of my lamp assemblies, grab a six pack and sit on my roof. When my necklace flashes I'll slam my last beer!!!
> 
> It'll be glorious man!!!



What an awesome thread.!:twothumbs


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## Juggernaut (Dec 17, 2008)

Timothybil said:


> Grounding would greatly improve its function, but the main idea is to create a space that the emp pulse is guided *around* and not allowed through.


 
This is what I never got about this whole silly thing, if your supposed to keep things in a metal box “say radio and it doesn’t get any reception then it works:twothumbs” well if the antenna is touching the box it will get reception “thus it would die” so a full metal flashlight’s internals are touching it’s own “box AKA it‘s body” so wouldn’t it just make things worse?


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## bodhran (Dec 17, 2008)

First of all...do you know something I don't? Second...how many lumens would your own body produce and would you really need a flashlight. Just curious.


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## Juggernaut (Dec 17, 2008)

bodhran said:


> First of all...do you know something I don't? Second...how many lumens would your own body produce and would you really need a flashlight. Just curious.


 
Yes do some resource, 



> This topic has been hashed to death before here and here.Also there's some more discussion here and here.


 
Obviously everyone will be worrying about more then flashlights in a nuclear bomb destruction radius. This is about when they are use only for their EMP capabilities in the atmosphere “where they will not damage anything on the ground and “lighting” will be a huge concern when allmost all power grids are down .


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## Sgt. LED (Dec 17, 2008)

bodhran said:


> First of all...do you know something I don't? Second...how many lumens would your own body produce and would you really need a flashlight. Just curious.


I think it's a joke post about somebody having previous knowlege that a bomb is on it's way. Not towards you - DO NOT ANGER THE JUGGERNAUT! 

I was going to post my ammo can thought but was beaten to it! And the Microwave idea tops it totally! 
Time to find a really big microwave....................


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## DM51 (Dec 17, 2008)

As mentioned above, this subject has been discussed exhaustively on several previous occasions. Links are given above, so this thread can close.


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