Airsoft Tripmine - CON 20
 

Maybe this should have gone in the Gear section, but I think it’ll be fine here too.

I’ve read alot of stuff about tripmines and airsoft “explosive type” devices on the boards lately, so I’ve had this thing for a while now, and have decided to finally throw this out there.

Several months ago I put up a post about something I call the CON 17. It was an airsoft mine I developed. The mines worked alright, but due to their small size you’d either need to plant them very efficiently in a high traffic area, or have plenty of them. The solution was to develop an airsoft tripmine, one that could be set off by crossing a line. Lots of R&D later I got the CON 20.

Now, I don’t know if this kind of stuff has been done before, but hey, I gave it a shot, it works well, it’s cheap, and home made, so if you’re still interested, read on.

The device is similar in design to the CON 17. The basic principle is that the mine is triggered, a CO2 capsule is punctured and either 1). BB’s shoot out of the barrel (apprx. 21). 2). Powder shoots out of the barrel. The powder (usually baby) is just for effect making a big plume of “smoke” and is typically used because it’s safer and easier.

The CON 20 is cheap to make, 100% reusable, very reliable, safe, and disassembles easily. The design has gone off without a hitch dozens and dozens of times in “lab conditions” (indoors, which means it’s tried and tested for CQB) and has been tested outdoors a few times flawlessly, yet has only seen actual outdoor combat use once (I hope to up that soon).

So here’s the technical breakdown. It’s very simple but you need an imagination to understand. At the bottom of a tube is a little spike. Midway up that tube a hole is drilled in which the trigger pin is inserted through the tube. A CO2 capsule rests in the upper half of the tube on the pin facing head down. Above the CO2 is a compressed spring. Both ends of the tube are held securely in place by pins. There is a hole near the bottom of the tube that leads to a barrel attached to the tube that runs along its length. When the trigger pin is removed the spring shoots the CO2 down onto the sharp spike, puncturing it, letting loose a bunch of gas. This gas flows through the hole in the tube and out the barrel creating a big pffft and either a shower of bb’s or plume of powder.

Total cost is somewhere around 5 bucks (not including the spring, I have yet to find a cheap, abundant and reliable source of springs). I’ve attached (hopefully) two pictures, as well as a zip file containing a little quicktime movie of the mine going off during a test (note: in the .mov the wire is manually pulled. You could string the wire between two trees and wait for it to be indirectly tripped, or you could set the mine, conceal yourself, then pull the cord when the enemy gets near, both work fine.).

Now, any Joe could make these, but not every Joe wants to or has the time to. What I want to know is, would there be any interest in the airsoft community for purchasing these trip mines? I’ve never seen a real tripmine before (other than claymores) but to be honest, I doubt these fully look the part. However, they do fit the profile of your more “terrorist like, improvised explosive device”. I don’t know the exact figures yet for pricing yet, but it’d cover the cost of materials, and a small (it would be small small, I’d rather get them out there in use than make an extra buck) fee for manufacture. If yes, cool, I’ll look into what can be done. If not, that’s fine too. If you want to make your own, great, just give a little credit and be safe.

So, any questions or comments are more then welcome. What do you think?

A link to test footage, more on the way. For me I had to right click this link and "save target as", I might just need a plugin or something though.

http://www.filelodge.com/files/hdd2/27151/CON20.mov

NEW:
Test footage of a slow walk indoors.

http://www.filelodge.com/files/hdd2/...ON20 Stalk.mov

More of a normal paced walk indoors.

http://www.filelodge.com/files/hdd2/...CON20 Walk.mov

Alex

Wow... looks pretty good.
I'd like to see one in action.

I'd pay up to 10-15 dollars for that kit

Phhh.. Cheapass, I think something like that would take about $40 or more + shipping, no idea though.

Any idea what the cost of these would be?

Well depending how big the video is, you can put it on www.filelodge.com , there is a 15mb limit per file though.

It depends on the cost. If it is cheep and easy to use I would buy one.

Ok, try this out

http://s52.yousendit.com/d.aspx?id=1...K28VIAU7L2AU77

It says it'll be up there for 7 days OR for a certain number of downloads (how many, I have no idea, so notify me if it's not working. I'll also give that other file lodge site a go, thanks).

Like I said, I'm missing the spring, key ingredient, but I'm giving a rough guess of somewhere between 10-20 bucks, then add shipping.

Alex

First off nice work, I myself have been trying to figure out "tripmine" Ideas.
I have a request! Can you take some sort tape and put it onto a tree or some open space so I myself and maybe others can see the mine work not just the smoke?

Im for this dont get me wrong when I mention this.

Im a tad concerned about the Nails, Pressure+Nail= projectiles. How does your mine work with the nails im not sure if they are just "pins" is there a way you can use small screws instead or possibly apoxy one end and figure something out for the other? Wooden dowel?

Besides that bud, get me photos of what the product looks like after it has gone off and a video showing it going off that the product is visible and I will more than likely buy one or two even.

Again Good Work, But you may have competition out there!! :P

Ok I just whatched the video but it seems like your realy TUGGIN on the trip wire to set it off. So if someone was running then ya they'ed set it off, if walking then no. Also it shoots strate up? maybe put something on the top to direct the BB's to the side? It looks good and the concept is right, I just feel that it could spend a few more days on the work bench.

I feel that any powder wont work for the majority of the airsoft community, people wanna get hit by BB's. Hope you find a cheap sorce of springs also.

-More sensitive trigger
-BB's shooting out to a side more than strate up.

That's a sweet design... I work at an Autoparts store that also sells industrial supplies... I've got a great selection of springs as well as other parts for the mine... Let me see what I can come up with when I get back from San Francisco next weekend. I'll have a complete list of parts and prices if you want.

Let me know

As for the safety concern, you are right to voice but I can assure it's just like any airsoft gun, if used properly it should be fine. All of the nails that are used (two safety pins and a trigger pin) have the ends filed down so they are very very dull. The two safety pins haven't shot out yet after dozens of trials and if for some weird reason they decided do, they'd be no more hazardous than a bb. As for the trigger pin, let me explain. I use fishing line for the trip line. It has a certain amount of elasticity to it, and I'm not sure if it's the tension of the line that shoots out the pin or the CO2 force, but the trigger pin will "shoot" a bit. In that particular video it hit my arm and gave me a little scratch, so always wear glasses, but otherwise again, no worries.

Trigger sensitivity:
The yank in the video is excessive. The more power the trigger pin is removed with, the sure...er.. (that seems weird) you are of having a clean detonation. However, I've also done tests of slowly walking through the line, and due to the elastic feature of fishing line, the trigger pin is still yanked out when the tension is too great, so it works well like that too.

BB's and Firing Direction:
If you wanted to use powder, but have it shoot AT you I could always redesign the barrel so it has a 90 degree angle at the end so it shoots towards your ankles rather than up.

For bb's, the 90 degree might work if it was a gradual curve to 90, but something tells me this would be tough.

I think though, that with some creativity, and maybe an extra nail or two you can make the mine detonate and shoot in almost any direction. But yeah, as was mentioned, a few more days on the work bench could change a lot so thanks for the comments/ideas and keep 'em coming.

Oh, someone also said "if it's easy to use". Yes, it is very easy, but here's the other bonus. For fun when I made them I made an operating manual, which is actually pretty thorough. Goes over deployment, mechanics of the mine, troubleshooting etc. So that idea is out there too.

As for spring talk, thanks a lot, anything helps. Feel free to PM or e-mail.

Lastly, I'm also working on getting some more video/photos so I'll try to do that asap.

Alex

What is the ruling on most paintball fields regarding CO2 cartridges, or devices like this? I think that's the major problem with all the mine/grenade ideas so far.

From the video, look like you need a lot of torque to trigger it.

Video link not working.

Cut the trigger pin down so it only catches the spring, maybe even add some grease to the end of the pin. This should cut the amount of force needed to trip the device.

I’ve been trying to tell people “you don’t need much force to set it off” but I guess the video looks deceiving. So here’s some new footage, walking through at a very slow pace I actually did this with the same mine 4 times in a row, two times at a normal pace (once the video didn’t record), twice at a slow pace (once without powder because it was getting really dusty, but I filmed one with powder also anyway) just to prove it trips easily and is reliable.

Here’s a slow walk. Again, if you don’t have the proper plugin you may have to right click and “save target as”.

http://www.filelodge.com/files/hdd2/...20%20Stalk.mov

There is very, very little resistance walking by, and if you were being shot at/not paying attention, or walking through a small bit of brush outdoors, BAM, you’d be toast. The mine is just sandwiched (but not actually held) by a vice so it doesn’t fall over and the other end of the wire is attached to a heavy box (please rest assured, I AM tripping the mine myself, there’s nobody off to the side yanking it). You can use obstacles, rope, tape, nails, or a combination of the above to secure a mine. For outdoors it can be as simple as digging a hole 3 inches deep with a knife to cover the bottom half of the mine.


To those who wish to see outdoor footage you’ll probably have to wait until the weekend since during the week I get home when it’s already dark. I'll get the other normal paced walking one up soon, though it's not much different. I have to go dust baby powder out of my house now…

Alex

Nice video but why does it have to be quicktime?

I'm not a big fan of quicktime myself, but it's done with the digital camera and that's just the format it comes out in.

Here's one at normal pace (hey, wadda ya know, normal clothes too).

http://www.filelodge.com/files/hdd2/...CON20 Walk.mov

Hey Guys,

After seeing this today, I thought I'd spend some time on formulating a "trip mine" that everyone can build for just a few dollars. I've built the first one tonight to figure out what needs to be modified. Tommorow i'll perform some revisions and post the results. Once completed I will include a parts list, how to build it, where to get the parts and for how much. So far on the first try the mine is working pretty well. Anyhow, check out the video. It was dark before I could test it. The film is displayed at full speed / 50% / 10%. This is a really easy (and safe) build. :salute:

TRIP MINE 8.7mb Quicktime

That's cool and all and I'm sure that's not how you're gonna set it up in a game... but I don't like the way it doesn't stay where you put it... It almost looks like it would hurt if it flew up and hit you.

I had some time at work today and went through alot of stuff that I could build one out off and have a few ideas... I think I found the perfect spring too... I think I can build a fully operational mine that can be easily be reloaded on the field for less than $25 after tax on all the parts. It'll take some minor modifcations to a couple parts and would be completely safe. I'm going into work tomorrow morning on my day off so that I can actually put it together... I've already got some jigs made too if I want to mass produce them... And I've got it set up so that I can change it from powder to bb's very easily... just need to work out how to fire the bb's effectively. Once I get it together tomorrow I'll take some pics and post em.

The problem with it right now is the firing pin. It's still a bit too snug. That's why it flew up in the air like that. Because of the force I had to use pulled it off the chair. I'm planning on building a stake on the bottom so it can be driven into the ground or some other easy method to attach it to a wall/door/tree. I figure one reusable trip mine might cost in the range of about $6-$7. The idea in the end is to allow it to be used on ANY surface.

My next step is to get a good firing system in place. I'm ultimately like to create on that can be set up to remote detonate. We'll see!

Very cool idea pizzainthemorning... honestly, I'd actually prefer using powder to BB's. But maybe you could show us some video of the mine using BB's anyways, just so we get an idea of how hard it'll shoot them out.

Here is revision number 4. This test was without powder. Just testing the firing mechanism. The trip wire still needs to be refined. It feels a bit heavy... and we all know we want a hair trigger! :-D

TEST 2 Quicktime 2.1 MB

If you guys want a parts list, here you go. I think all of the parts can be found between dollarama and CT (or other hardware store).

1 Aluminum Hollow Broomstick (Cylinder)
2 Vinyl leg tips (Endcaps)
1 Cushioned nail-on glide (Spike)
2 Small nails (Safety pins)
1 Larger nail (Trigger pin)
15’ Fishing line (Tripline)
1 Spring (….Spring)
1 Faucet Robinet (Barrel)

Add tax and total is roughly 5 bucks. And if you want a cross sectional drawing (it was done quickly, but hey, you get what you’re given) here you go too. Go nuts.

As for a video of shooting out bb’s, I can try to get one, but it’ll be very hard to do, as you really won’t be able to see the bb’s. If you want an idea of the force, it can travel roughly 50 feet tops (being fired horizontally from shoulder height. I actually made a gun-rig so I could shoot it at stuff if I wanted), has a very large spread, puts a huge dent in pop cans but is definitely unable to penetrate one, which I think is pretty good since you don’t want a 22 bb’s hitting your ankle or face or whatever at 400 fps. Enough to know you're hit, not enough to injure.

Alex

Very creative design
the simplicity is just brilliant
In regards to the stretch in the tripwire why not try using a different fishing line like Spiderwire, it has very little stretch and is very fine in diameter.

Thanks, glad to hear the appreciation. Fishing line does have that bit of stretch but it's not really a bad thing and in fact may work to everyone's advantage. It's also cheap and readily available, but this spider wire also sounds intruiging. If I knew where to get it I'd take a look. Thanks.

Alex

You can find Spiderwire at Canadian Tire in the fishing section but any store that sells fishing tackle will probably have it. It comes in a black box and costs more than regular fishing line but it is much more durable.

If you are looking for a compression spring. I found mine at an auto parts store. Fairly inexpensive.

pizzainthemorning... what did you end up using for the spike? How is it secured?

I'm using a stainless steel screw right now, but i'm getting inconsistent punctures on the top of the C02 cylinder.

how do you reload it?

Can you put mutiple barrels?

You could in fact put multiple barrels, but the distance of the exhaust would decrease. Reloads are simple. You just take the cap off the end and put in a new CO2 cylinder and reset the trigger pin.That part takes only seconds. As for "easy" reloading of the powder... i'm still workin on that one myself...

so you just drop some bb's into the barrel i presume?

Try wrap the powder into one of those plastic wrappers. Use one layer, and stick it into the barrel. Also, what would happen if the powder gets wet?

Oh! OH!!! Instead of powder, use red jello! :lol:

Yes, bb's do just drop into the barrel. I've carved a tiny lip on the barrel that prevents them from coming out unless you really really shake it hard or set off the mine.

Easy reloading of powder. I've been thinking about this and here's my idea. Ever put a straw in a drink, cover one end with your finger and contain some of your drink in the straw? Well, same idea, except I guess the ends would have to be taped, and then just fill the whole thing with powder before hand. Then when it's time, just let it transfer and slide out into the other barrel. Also, though the powder is better, it could be used in emergencies (or if it was raining and would get wet anyway) without the powder. You still get the sound and a smaller pft. effect of CO2. I'll work on getting out a video showing how easy it is to reload.

Cratedriver, you asked what I used for a spike. It's on the parts list a couple posts back, cushioned nail-on glide or something is the technical name. The beauty of the design is that I don't have to secure it, it's just put in and is secured, which is great because the only maintenance this mine requires is the occasional (for optimal results that is, you can use it 20 times in a row no problem) sharpening of this spike, and since it's not fixed to anything, you can take it right out.

Alex

Sounds like an execllent product. User friendly and so simple that even I can understand it.

Ahhh! That's brilliant! I know exactly what you're talking about.

As for the housing... i'm using PVC/ABS 3/4" pipe with endcaps. It has a pressure rating to 480 PSI. So i'm quite confident in its ability to withstand explosive gas expansion and not fall apart.