Could be handy
A reader emails that he’s looking to make his gun safe’s electronic lock Electromagnetic pulse proof. Thought it was an interesting question. Thoughts?
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November 21st, 2011 at 1:08 pm
If you’ve already laid in survival supplies, backup generators, escape routes, bug out bags, etc etc etc its really one of the last logical steps.
Of course this all assumes that getting a safe with a key or combination lock is off the table.
November 21st, 2011 at 1:12 pm
If he’s that worried about it, get a mechanical lock.
November 21st, 2011 at 1:13 pm
EMP proof? Get a mechanical lock.
November 21st, 2011 at 1:29 pm
An EMP pulse is an electromagnetic pulse. An electromagnet on steroids. It will induce a voltage spike in anything conductive, unless “anything” is protected from magnetism.
If you have something electronic you want to protect from an EMP pulse, a good tight metal box will likely do the job. For more protection wrap the “thing” in “mu metal” foil, and make sure to crimp all the seams.
The first thing on my list of things to be protected is not electronics, though. It is the backup generator, which is not shielded, and whose coils make a wonderful secondary for the EMP primary.
Stranger
November 21st, 2011 at 1:32 pm
I bought an EMP-proof safe. It’s called a mechanical combination lock. :/
November 21st, 2011 at 1:33 pm
“If you have something electronic you want to protect from an EMP pulse, a good tight metal box will likely do the job”
Uh, isn’t a safe a “big metal box” ? Maybe all that needs to be done is to ground the chassis of the safe.
November 21st, 2011 at 1:37 pm
There are two basic ways to protect or harden items against EMP effects. The first method is metallic shielding. Shields are made of a continuous piece of metal such as steel or copper. A metal enclosure generally does not fully shield the interior because of the small holes that are likely to exist. Therefore, this type of shielding often contains additional elements to create the barrier. Commonly, only a fraction of a millimeter of a metal is needed to supply adequate protection. This shield must completely surround the item to be hardened.
The second method, tailored hardening, is a more cost-effective way of hardening. In this method, only the most vulnerable elements and circuits are redesigned to be more rugged. The more rugged elements will be able to withstand much higher currents. This method has shown unpredictable failures in testing, though it is thought it may be useful to make existing systems less vulnerable.
November 21st, 2011 at 1:37 pm
Other than the obvious mechanical solution, the safe would need to be enclosed in a Faraday cage, and the power supply would need to be protected using a Zener Diode (I’m not an EE but have heard that Zener Diodes are appropriate for this.) Of course this assumes that there is battery backup (my Winchester hand-safe takes eleventy AA’s).
Mike
November 21st, 2011 at 1:39 pm
Want to protect an electronically locked safe? Stick it in a larger, mechanical safe. Imagine the frustration on the criminals’ faces as they break through the outer safe to find another one inside… Especially if you do this repeatedly, like a matryoshka doll. Heck, I’d put up signs saying “Break into this safe!” just to watch their reactions.
November 21st, 2011 at 1:40 pm
I wouldn’t be surprised if the safe wasn’t already hardened enough. If a general atmospheric EMP could take it out, then it would be horribly vulnerable to sparks and direct applications of current, and that just doesn’t make sense for a safe.
November 21st, 2011 at 1:40 pm
Yep, it’s an easy fix: replace it with a standard mechanical combination lock. Electronic safe locks are nifty-neato, but they have problems:
1) using the same combination puts wear on the same numbers on an electronic lock, and unless your combination uses all 10 numbers, the wear patterns reduce the options for unauthorized persons, making the safe easier to get into.
2) electronic locks, occasionally, develop problems, which the manufacturer can fix after a few days. If you need something from the safe today, you’re SOL until the electronics-trained safe technician arrives.
3)Mechanical combination locks aren’t completely unbreakable, but they’ve been around more then long enough for Those Who Know Them to have developed some pretty good locks.
4) Most good safe shops can fix a combination lock. Today.
5) The EMP issue mentioned above.
November 21st, 2011 at 1:57 pm
I keep my safe in an underground bunker. I can access by a pair of fireman poles hidden behind a book shelf. The bookshelf slides open when I turn a switch hidden in a bust of Shakespeare. The electronics down below are pretty safe.
November 21st, 2011 at 2:02 pm
V-line makes pistol safes with mechanical locks.
November 21st, 2011 at 2:25 pm
Safe? You guys keep your guns in safes?
But…what do you do when the ninjas suddenly invade the house and you need that firearm immediately? Without the light or the laser of course……or the tracer ammo….
Just had a thought….would EMP fry any “electronic” fingerprint…whatever thingamajig, that the Brady’s always want…to restrict the gun use to the owner?
November 21st, 2011 at 2:38 pm
Ditto here.
Get a safe with an S&G combination lock.
Electronic locks are useless once the batteries die or the guts get fried.
November 21st, 2011 at 2:41 pm
Cargosquid: Such a gun mechanism on a weapon I owned would be removed long before any EMP got to it.
November 21st, 2011 at 2:41 pm
There is EMP, and then there is EMP.
One kind is when the Sun does a coronal mass ejection, and a magnetic storm hits Earth. That can do all kinds of harm to the powerline grid, but if something isn’t plugged into the power grid, it’ll be safe. The electronic safe uses batteries.
The other kind is caused by an EMP weapon. The fields are higher, the wavelength shorter, and this is the one you need to shield the safe against. It isn’t likely to happen unless there are international problems that definitely require a gun. For that, the mechanical safe is better.
If you have an electronic safe and there’s international tension, cover the keypad and its surroundings with conductive aluminum tape. That’ll probably do the job.
November 21st, 2011 at 3:19 pm
Mine has a keyed backup. Don’t all electronic safes?
November 21st, 2011 at 4:19 pm
Someone already mentioned faraday cage.
November 21st, 2011 at 4:32 pm
Congress did a report in 2008 on the effects of an EMP: http://www.empcommission.org/docs/empc_exec_rpt.pdf
Read if you want details, but it seems like some of the EMP threats are overblown. For instance, most cars with electronics will keep working — according to their tests. I bet non-grid connected safes would too. Besides, all mine have keyed backups.
November 21st, 2011 at 4:34 pm
As far as the electronic pistol safes… Youtube “bumping electronic safes” and see just how easy most small electronic wall and freestanding safes are… Usually about 10 seconds and a thief is in… Just my 2 cents…
November 21st, 2011 at 5:37 pm
Bob Owens, if your safe is like my electronic-lock one, it’s easy to remove the electronic lock mechanism to expose the mechanical lock. Now, I wonder if those two, 200-year old-style keys are really unique, or if they are some sort of skeleton key? The safe is a Sentry 14-gun. I have another one of those, but it has a combo-lock.
November 21st, 2011 at 6:16 pm
Wow… Ok… So not many EEs here it seems!
Like Jamie said… Movies EMP are not equal to Real EMPs.
Let’s look at an electronic (S&G) lock. I have yet to tear one apart but I do intend to whenever I get one that isn’t attached to a safe. The basic components on this type of system are Power Supply, Microcontroller, and Relay. There isn’t much more to it. Perhaps an off-board EEPROM but I kinda doubt it actually.
The Power Supply consists of the 9V battery of course, but also a few capacitors to de-couple or level out the voltage and almost certainly a 5V or 3V regulator. It’s almost unheard of in the last 10 years to not add at the least some combination of a reverse biased diode, transient voltage suppressor, extra decoupling caps, a reverse biased zener, etc etc. So let’s just say the power supply is the most rugged part of the system.
The Relay is going to trigger the armeture to unlock the safe of course. Also rugged. This relay may be 5V or it could be triggered from the 9V battery directly. The only susceptible component in this application would be something like a single gate MOSFET (basically a switch that uses a little power to trigger a much bigger flow). Since MOSFETS are susceptible however, engineers ususally protect the crap out of them. Most likely though a more rugged transistor is used to switch the relay. Again with reverse biased diodes and etc etc.
The Microcontroller itself isn’t going to be an issue unless the design is poor. What could be an issue is the links between the micro and the rest of the circuit. These links become antennas for the radiation of the EMP. But… again, these circuits are usually protected from expected transient signals.
So… If the lock was designed worth a shit and the EMP isn’t right over your head, your lock SHOULD be ok. The safe is going to protect it and if S&G uses a gasket and a metal plate for water and theft protection these are all going to help protect the circuit. All said… I’m not worried about my safe lock but I AM ASSUMING that S&G has engineers worth a damn.
The real threat is from telecom or radio signal devices. Anything that has an antenna is going to more at risk because it’s designed to pick up current from the air. Engineers usually don’t consider that an extra 500mA is just going to randomly appear so things like this usually get skipped over.
November 21st, 2011 at 8:11 pm
I have 2 Cannons with electronic locks. If I was to do it over, I’d definitely go mechanical. My parents broke one of the electronic locks replacing the battery (older people and technology don’t mix). Oh that was fun to fix! They were on the verge of having a safe specialist drill the safe (the moron didn’t even try to reconnect the leads). I have been meaning to replace that one with a mechanical lock but I haven’t been to that house in a year or so.
Go mechanical! It’s less cool, less high tech, less likely to break. Electronic safe locks break.
November 21st, 2011 at 10:39 pm
Try a Kaba X-09 lock – only about $1500.
November 22nd, 2011 at 12:06 am
The X09 is a good lock. No battery to change, electronics are reasonably robust – but I’ve replaced at least three that wore out mechanically. Granted, we were in and out of the safe a LOT, but keep it in mind. As far as EMP resistance, the poster who mentioned aluminum tape is right on the money.
And my primary SHTF vehicle uses points.
November 22nd, 2011 at 1:26 am
Yeah, lemme tell you about that KABA. First one we installed was on a marine weapons vault(in San’na, Yemen, we replaced a KABA X-07)…one week later we were drilling it out because IT HAD FAILED. And all of the self charging KABAs have the same problem – the charging mechanism has a definate life span.
November 22nd, 2011 at 1:49 am
My first instinct would be to use lead, but as no one has mentioned it yet, it seems it would not be a good method to protect against an EMP burst.
November 22nd, 2011 at 5:10 pm
EE here. I bought a mechanical one. Wouldn’t even consider the electronic ones. I could explain, but it looks like it’s been covered. I also know how to make a faraday cage, and the safe will require some work to make it even a single layer one.
November 25th, 2011 at 6:32 pm
I’m wondering if the dehumidifier/heater unit inside a safe would act like an antenna to rebroadcast the EMP inside the safe? You know, that unit hooked up to the electrical grid?