# Gadget makes bombs, mines go off 'on average' 20m away

Colombian and Swiss boffins say they have developed a cunning electromagnetic device which can make landmines or terrorist bombs explode from a distance. Félix Vega and Nicolas Mora, doctoral students at the école polytechnique fédérale de Lausanne (EPFL) in Switzerland, developed the bomb-triggering device as part of their …

## COMMENTS

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#### Or...

Or it could be used to clear up mine fields from wars long gone, iirc the Falklands have beaches covered with mines, a device like this attached to a remote control vehicle could easily help clean the beaches of mines and make the place safer as well as remove the need for sending a bag of flesh in there to get blown up.

#### Do you mean

"attached to a remote control vehicle" as in "attached to the back of an ASBOed teenager left free to run on the beach"?

More environmental, and sensible

#### Possibly...

But it sounds like it only works on electrically triggered mines, while the really old ones lying around would more likely be purely mechanical.

#### It's all about the mines already in the ground...

Although it probably won't deal with the really old ones that are purely mechanical.

However the problem for many ex war zones are the mines already sown, not those yet to be planted.

#### Stats fail

"And "an average of 20m" means, of course, that half of the devices detonated closer than that."

Um... no it doesn't. If they'd said that the median distance was 20m, that'd be a different story.

#### mean, median, mode, meh

Even if the median distance was 20m, that wouldn't mean that half of the devices detonated closer than that. Consider this sample set:

(1, 18, 19, 20, 20, 20, 20, 23, 29, 30)

The mean, median, and mode are all 20, yet only 30% are less than 20. Did you mean less than or equal to? Well, 70% are less than or equal to 20 -- that doesn't really help either.

Mean, median, and mode are very poor predictors by themselves. Standard deviation and a model of the distribution curve are pretty much required for any serious analysis.

#### Steven Knox got it wrong

Your argument fails because you assume that distances can be measured exactly.

Those 4 20m measurements will really be scattered about 20m. ie something like 19.950, 19.987, 20.003, 20.334

When you're dealing with non-integer values mode has pretty much no meaning at all.

But your main point is correct. The std deviation and characterization of the curve are more important. You could get a 20m average out of ten samples if one was at 200m and the rest were at 0 m.

#### Without bothering to read the thesis....

Presumably the power that the gizmo can radiate to a range of 20M is sufficient to detonate the average bomb. Now even if the power just drops off on the the inverse square law (inverse cube is more likely here.) at a range of 10M the strength will be four times higher.

Assuming that the detonator sensitivity distribution curve is gaussian, median=modal=mean, and this WILL hold even after the power mapping hinted at above.

After the mapping, detonation rate per metre outside of the 20M radius will fall quickly, as both the distribution and the received power fall, just inside the "average" radius it will fall rather less quickly, since the power will get much greater as you approach the transmitter, and near the peak of the gausian distribution the differential is near zero. Put simply... half of the mines will blow before 20M, and the power available to blow mines at 10M will be four (pos eight, can't be bothered to read.) times as great as that.

Even if the variance of the first bell curve is wider than my ex girlfriend's bum. (Whch had it's own gravitational pull, no matter what she was wearing.) A simple grasp of A level stats shows that the overwhelming majority of susceptible mines will blow ata a safe(ish) distance.

#### But on the other hand

Roadside bombs aren't the only game in town here. There are still millions of mines strewn across wide areas of the world, and even in-situ detonation would be strongly preferable to the usual method of "discovery by (soon to be ex-) goatherder".

#### Remote detonation mechanically...

The long piece of string might be noticed?

#### 20m is better than nothing!

I would rather the device went off on average 20m from me than on average 0m from me without the technology..

#### Presumably...

the soldiers handling the pulse-bot are carrying a few bits of explosives themselves.

Either those handling the bot must be (a) a LONG distance away from it, just to be safe, or (b) unarmed.

None of which seem to be very attractive.

#### explosives on the soldier

It doesn't just blow up any explosive within range - it triggers electronic detonators. The soldiers handling the pulse-bot are fine if they don't carry electronic detonators attached to explosives. Although I can see that could be a possibility, it's hardly equal to "unarmed".

#### lol

Ideally you want to be a little further away than 20 metres, something more like 200 metres.

This post has been deleted by a moderator

#### Mines?

Not all mines are electrically initiated, so this device would be of limited use in mine clearing unless you could be sure of what types of mines were used. And even then I'd be careful...

It's still an interesting development though, and I'm sure its effectiveness will improve.

#### Missed out...

Using high-power radio waves to trigger the things is OK, but there are reasons for EMC directives. They said that they blew-up explosives at an average of 20M, but forgot to say that they also...

...blew up computers, TVs, radios, phones, etc. at an average distance of 200M

(When EMC testing a car once, we set alight the wire-wound resistor that allows the windscreen wipers to go at "normal speed" as well as "typhoon speed".)

#### Nitpickers

AndrewH: 'Average' could mean mean, median or mode - however many people do baselessly assume mean as you have - so I have amended the article.

Rest of you: Most mechanically initiated mines/devices are of course victim-operated or timed, not command. However failed impact or time fused munitions - especially cluster submunitions - can also in effect function as VO/boobytrap landmines. That's mainly what I was driving at, and these several kinds of non-electronic munitions or devices constitute the majority of the 'landmine' problem worldwide, so this gizmo really isn't going to be much use for minefield clearance.

However there are plenty of ways to have a non-electronic command device, too. You could easily use a long length of detcord, for instance. So have a think before hitting post, smartarses.

And David, since this gadget will not set off many devices you are likely to encounter, they will still go off right next to you.

#### falklands - sheep

Plan B : I could never understand why in the Falklands they didn't just run flocks of sheep through suspected mined areas, even beaches. If the sheep weren't heavy enough of themselves, there's plenty of rocks could be tied to them.

Plan A was of course to run the "invading soldiers" across the land instead, but such things were probably not allowed.

#### Livestock

Livestock do not guarantee 99.9% clearance over a wide area. That's why they are not used.

That said, I am lead to believe that there are some 3 legged sheep wandering around the FI.

#### eltit

AC wrote: "Plan B : I could never understand why in the Falklands they didn't just run flocks of sheep through suspected mined areas, even beaches. If the sheep weren't heavy enough of themselves, there's plenty of rocks could be tied to them."

... if they used the sheep, then what would the islanders do for a little lovin' on those cold and lonely nights?

#### AC@17:58

"Plan A was of course to run the "invading soldiers" across the land instead, but such things were probably not allowed."

Captured Argentinean soldiers were indeed used for "mine clearance" duties in contravention of the relevant articles in the Geneva Convention by the parachute regiment.

Much as they did in WWII in Italy.

Lucky if they only had to deal with carefully placed hand grenade.

#### Because...

the farmers didn't want to lose their 'loved" ones?

#### AC Wednesday 16th February 2011 21:04 GMT

"Captured Argentinean soldiers were indeed used for "mine clearance" duties in contravention of the relevant articles in the Geneva Convention by the parachute regiment."

Do you have any links for this? I understood some Argentinian sappers volunteered their assistance to mine clearance (because they had the maps) and also helped to repair water treatment equipment - but your comment implies coercion, so it would be interesting to know the source of this information.

#### Me too

I'd like to see the evidence of this too, Piers.

#### Is this directed or omni?

That could really suck for anyone using "electrically-actuated detonators" that have the explosive on them and not in the ground yet. If the plane or truck wielding the gadget gets too close, *pop*

#### Sauce for the goose?

What is to keep the bombers from using these as detonators? Or initiators? IE, set up the bomb so that one of these pulses will activate it, but the real trigger is a timer or some sort of proximity sensor... A good idea for sure, but not the panacea that I think the inventors believe it could be.

#### Lewis is the best poster ever

He's like a shark who won't even come shallow until there's twenty swimmers on holiday and one of them cuts a foot on a bit of glass.

Can I be automatically notified of Lewis Page's future comments, please?

Paris, because since the inclusion of her icon here I've generally found nothing else satisfies.

#### Lewis icon

Yeah, and he can prob use the same icon as our dear moderatrix too, but I see he prefers something more familiar :)

#### The Trigger

See the Arthur C Clarke / Michael Kube-McDowell book for one possible future, it's not all good!

#### Easy one

All those pesky IEDs in the stan? Then what is needed is a vehicle packed with Insurgents, out for a nice ride, nice to get out of prison. Remote driver, and bingo! or rather BOOM! insurgents kill truck loads of insurgents. or all those murderers doing time? Give em a bomb disposal course, if they object (human rights shite) they can take a ride in a van in a hot country.

Or never fight a battle where we have nothing to gain? sorry Sun Tze

#### Mines - really?

So this can generate a high enough field that a bit of wire in a detonator, inside a metal mine casing, buried 0.5m under water logged soil gets a high enough current to vapourise and detonate the charge ?

#### e-m radiation

"mechanically, without any electronics in them at all: no amount of cunning electromagnetic trickery will work against such a device."

umm... electro-MAGNETIC radiation can affect non-electrical things. If done correctly, it could presumably vibrate whatever ferrous metal that's in range, generating friction against the non-ferrous and thus detonating any explosives.

Might be slightly far-fetched, but certainly not "no amount of cunning electromagnetic trickery"

However, I do wonder how many indigenous peoples with pacemakers will welcome this tech!

#### Expendable unit?

The device could be a remotely deployed, expendable item, though? A bit like some ROVs that placed a bomb next to a seabed mine and fired it remotely?

Possibly some electronics and a battery would be cheaper than an explosive device - and the device would also not have to be secured and handled as a munition.

#### I assume the antenna is the only thing that needs to be within X distance

So exactly how is this an issue? Antennas are cheap (as compared to the amplifier etc). So launch your antenna into the middle of a mine field, turn it on, haul back what's left, fix/replace the antenna, rinse and repeat.

Or even better, walk the antenna into the field attached to a elcheapo bomb disposal robot, I assume that they are reasonably robust.

On another note, I assume that what they are saying is they've found a narrow range of resonant frequencies for detonators.... which seems to mean that there is a narrow range of frequencies to listen to to detect a detonator.

So why not just do a wide band pulse, and listen on those frequencies for re-emitted EM of the detonators, triangulate and map.... seems to be a lot more power efficient than trying to actually blow them up.

#### @AC 21:11

Cheaper? Do you have any idea how ridiculously cheap a chunk of C4 and a detonator are? You can't even buy a milspec laptop for that kind of money, let alone a piece of electronic trickery designed to remote detonate stuff so there's no way in hell it's going to be cheaper.

And you're more likely to lose the robot you attach it to, since the one with the C4 and detonator just has to roll up, drop the C4 and move back to a safe distance. It could set the IED off prematurely while doing so but that's a chance. The robot with the electronic gizmo is guaranteed to set the bomb off while it's nearby.

And you're right, it wouldn't have to be secured and handled as a munition. Instead, it would have to be secured and treated like a piece of fragile and highly classified electronic equipment.

And if you think they treat secondary explosives with extreme care, you're sorely mistaken. Not that it matters, since a secondary explosive is pretty much impossible to set off without a detonator in the first place. The detonators do need to be handled with care, but mainly because you need them later, not because of the damage they could cause if they did go off.

#### what is the reply button for?

To the enemy, the cost of C4 is not just the purchase price, but the time and expense of smuggling it into the conflict zone and then deploying it.

As for the transmitters needing to be handled like "delicate electronic equipment", think about the remote vehicle locking transmitter in your pocket, or your satellite TV remote control.

And one final point, the transmitter won't be highly classified since it is described in a published doctoral dissertation.

#### Another application for ferrite 'balls'!

Just think the terrorists answer lies in adding those ferrite 'balls' to the trigger wires.

The detonators could be housed in metallic jackets - their own little Faraday cages.

Back to the drawing board.

#### Useful

20m isn't bad. Stick it to the top of a radio controlled (or cable if the radio get screwed up) and operate it from 250m away. Or as suggested strap it to the asbo yoof and let them run up the minefield. Or just send the yoof up and save money on the equipment. A new gambling game invented.

Why not just make a big feckin armoured bulldozer with a large flail and remotely drive it around the suspected field. Did that not work in the past?

#### Um.

Most detonators I've seen are cased in a thin shell of aluminium.

I do not want aluminium shrapnel to emit from my pockets tyvm.

You need some bad luck to be killed by a detonator alone, but the injuries can be unpleasant nonetheless.

There was an incident in the Nowergian corps of engineers 10 years ago or so where a demolitions instructor had been careless and rigged a small lump of HMX with an electric detonator and carried it in his pocket "for the next demonstration". And then the 200 watt HF radio in the car behind him started transmitting. He lost his leg.

Grenade obviously.

#### They've missed the real market

If they sell them to the [choose your miscreants], then THEY can be deployed along the roads outside of military bases, etc. After all, fair's fair.

#### In fact some of the current mine field clearning devices work by detonation at 0m

In fact some of the current mine field clearing devices work by detonation at 0m.

You have a special purpose truck and a series of weighted trailers of varying axle width. They work by rolling over the mine.

Others use a chain flails mounted on steel axles to set off mines a few meters in front of the vehicle.

They are going to be much more expensive than a radio antenna and 20 m of boom.

20 m is over 60 feet. It is a pretty good horizontal distance, keeping in mind that for buried mines most of the explosive force is directed upwards.

You won't want to be in shirtsleeves at 20 m, but you won't need 10 cm of armour either.

#### juice up the power supply and 20m becomes 60m

Juice up the power supply and 20m becomes 60m.

Likewise, a directional antenna would boost the range without needing an increase in power, but perhaps they already use a directional antenna.

A production version would need some shielding and a directional antenna.

I imagine it would be truck mounted with the antenna on a boom.

It will force mine builders to either electrically shield their devices, making them both more expensive and more detectable, or to make them mechanical with more easy to detect metal parts or more complex to manufacture plastic parts.

#### Up the Arsenal!

Sounds like an offensive weapon to me with the potential to take out an enemies ammunition dump.

#### Filtering?

If the frequency ranges involved are narrow, would it be hard (or expensive) to tweak the connections to a detonator with appropriate capacitance/inductance to filter out the attempted interference?

If the detonation is just from heating, would something that worked as a short circuit for high frequency interference get in the way of a detonator being set off by a DC voltage, or is ultra-rapid risetime/heating necessary for detonation to work properly?

If gadgets like the one described were actually widely used, someone with a mind to experiment might set up various simple test devices, and fairly quickly work out (from a safe distance) which ones were and weren't detonated by a passing patrol.

I wonder, if someone was using one of these units and it had successfully set off (or seemed to have successfully set off) a few small devices at a distance, would that generally make them feel more confident about proceeding, or less confident?

#### Or...

Set them in (peace loving) Islamic nations to pulse once a second. This would make arming a terrorist bomb an instantly lethal exercise.

Premature detonation is sooooo embarassing.

#### A.C. Clarke beat them to this

Read the Book "The Trigger" :)

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