Made entirely from parts found in the 1$ store, these use a very small toy-grade explosive to make a nice loud BANG!
WHAT THIS IS
This is a harmless tripwire-activated “mine” that you can build yourself entirely from simple materials purchased from the dollar store, or found around the house. It uses caps from a cap gun to make a surprisingly loud but harmless BANG! when activated. Caps are explosive, but they are perfectly safe to use. Like the Sonic Grenades, this can also be used to liven up your NERF or Airsoft or Paintball games (or torment roommates who make their sleepy way to the bathroom in the middle of the night.) They’re made to use outside, but they can easily be used indoors as well. They are also the opposite of the Sonic Grenades in that they are completely non-electronic.
You set it up, stretch out a tripwire (fishing line, string, or wire), and as soon as something pulls on the wire you get a nice, loud BANG!
INSPIRATION
A fellow I know had some stamped-metal cap-powered tripwire “mines” from somewhere. I liked them, but immediately began thinking about how to make one out of household materials. I was successful, and here is the result. It entirely uses common items in ways that have nothing to do with their original purpose (that’s something I like doing.)
HOW IT WORKS
A tripwire, once stretched by someone walking across or pulling on it, pulls on the trigger lever of a common mousetrap – releasing the trap’s spring-loaded arm.
The mousetrap’s arm is used as the hammer to detonate a plastic cap. The cap sits on the head of a nail driven through the body of the mousetrap – this both holds the cap in place, and serves as an anvil upon which the cap will be crushed.
The sound is surprisingly loud for a toy cap – thanks partly to the force behind the mousetrap’s arm which ensures a quick and reliable ignition of the cap. Also, multiple caps can be put on a single trap – such that the arm hits all at the same time – in order to increase the sound level. In this example, I made one with two.
PARTS NEEDED
- Mousetrap (nothing fancy, just the ‘classic’ model).
- Plastic tent peg (or a shapened piece of wood or other stake).
- Spool of thin floral arrangement wire (green) OR spool of monofilament (ie fishing line) for the tripwire. Green wire is better outdoors, monofilament is better for indoors.
- Elastic band.
- Some caps for a toy cap gun (the plastic ring kind).
- Some finishing nails (nail head needs to be small enough to snugly fit a cap onto it).
- Some miscellaneous screws for mounting the mousetrap to the tent peg.
- A drill will be useful, too.
This particular way of making the mine assumes they will be used outdoors (hence the tent peg for shoving it into the ground).
HOW TO MAKE IT
Step 1: Secure the mousetrap to the tent peg
I did this with a couple screws. You may need to pre-drill the hole depending on the size of the screws to prevent the trap or peg from splitting.
The REAR of the mousetrap is now the FRONT of our mine – it is also the side the tripwire will be coming out of.
Step 2: Drill a hole for the tripwire to access the trigger
A small hole through the body of the mousetrap will allow the tripwire access to the trap’s trigger. Since the trap’s trigger is a lever which must be pushed to release the arm, we can’t have anything in the way of the arm’s swing, and a tripwire pulls instead of pushes — we drill a hole so the tripwire can pull on the release lever from behind.
That may sound a little complex, but it isn’t really. Just consult the picture.
Step 3: Insert a nail for the anvil
Pick a spot on the trap where the arm is at rest to put the anvil. Drive a nail through the trap body (and also into the peg as necessary) to serve as the anvil for the cap. The arm must strike the top of the nail as squarely as possible when it comes down after the trap is triggered to ensure it crushes and ignites the cap on the nail. If necessary, pre-drill a small hole so you don’t split the wood with the nail. The nail’s connection will be more durable if you drive it into the tent peg, too.
You can experiment with more than one anvil if you wish for louder sounds from multiple caps. For example, I went ahead and used two in a couple tests (one on each side). It doesn’t matter where the nail goes as long as it’s secure and the arm strikes it squarely. You can bend the arm out of shape to make it fit the location of your nail if needed.
Step 4: Put the elastic around the trap to strain relieve the tripwire
As you are probably aware, it doesn’t take much to set off a mousetrap! If we attached the tripwire directly to the trigger lever on the mousetrap, we would not be able to actually stretch out the tripwire because as soon as we pulled on it even a little, the trap would go off!
So, we use an elastic band to get around this problem. See the pictures for how to attach the tripwire to the elastic band.
One end of the tripwire is anchored to something immovable, and the other end is attached to the mousetrap’s trigger lever. See the picture below for an example of a primed mousetrap with the end of the wire attached to the trigger lever.
But before the tripwire leaves the mine, a loop of tripwire is tucked into the rubber band. This makes the tripwire hold fast unless it is pulled on with some nontrivial amount of force.
When pulled, the tripwire will pull out of the rubber band’s grip and pull on the mousetrap’s trigger lever and BANG! The mine goes off! A tighter rubber band will mean a less sensitive tripwire. A looser rubber band will result in a more sensitive tripwire.
Step 5: (Optional) Spray paint it black or green
Because nothing says “tactical” quite like a green or black spray-bombing. Oh yeah.
HOW TO USE IT
- Drive the mine into the ground by way of the attached tent peg. Remember the REAR of the mousetrap is the FRONT of our mine which is where the tripwire will come out of!
- Securely attach one end of a tripwire to an immoveable (or suitably heavy) object such as a tree.
- Take the other end of the tripwire and tuck a loop of tripwire into the rubber band wound around the mine’s body. Hold it in place with your fingertip while you adjust the tripwire so it is taut. Leave some excess for the next step.
- Thread the remaining end of the tripwire through the hole in the body of the mine, so that it comes out by the mousetrap’s trigger lever.
- Attach the tripwire to the trigger lever, or (in the case of using wire as the tripwire) just ball up a little of the wire. We want it so that when the tripwire itself is pulled, pressure is applied onto the trigger lever which releases the mousetrap’s arm.
- Gently lift the arm of the trap enough to place a cap on the nail’s head. Secure it in place with a small piece of tape over it if needed. If you selected a nail that the cap can fit over snugly, the cap will hold itself in place and the BANG will be louder.
- Set the mousetrap in the usual way – by bringing the arm down, and holding it in place while the bar is placed across the arm and hooked into the trigger lever.
- Now when the tripwire is pulled, it pulls the loop out of the rubber band’s hold and trips the trigger lever which will release the arm of the trap, which will crush the cap between the hammer (mousetrap’s arm) and the anvil (nail). It sounds a little Rube Goldberg-ish when it’s put like that, but it’s really much simpler in practice.
DEMO
Here is a little demo of the assembled unit zip-strapped to a table leg (no dirt in the basement to drive the peg into, after all) and a video of the tripwire being triggered.
