For whom the bell tolls…Improvised perimeter alarms.

I recently had a reader contact me and ask for a post on improvised perimeter alarms. He had read about some of the examples that I had mentioned and asked if I could devote a whole post to them as he was very interested. Well todays post is for him and I will cover all of the ones I know of, so If I miss any, please let me know in the comments below so we can share them with the others as well.

Improvised perimeter alarms can cover a lot of ground and can get very complex. For the purposes of this post, we will try to stay to the simplest ones that can be setup in very little time and involve few parts. I am sure that as time goes on and SHTF hits, people will come up with other ingenious ideas for telling if there area is secure from intruders. Some of these you may already know about and some of them may be new to you. I hope you enjoy todays post.

Building a better mouse trap!

There are a couple of ways to use a mouse trap for this purpose. You will first need to mount a mouse or rat trap to the side of a tree away from your campsite. Then you will want to string a trip wire around the area from the trip mechanism on the trap. When the trip wire is pulled, it should cause the trap to fire. At this point you could do several things. One way is to attach a chemical light to the trap so that when the trap is fired, it will break the vile in the chemical light causing it to glow. This works great for night-time security, but not so much for daytime use. Another idea is to attach a string with several small bells to the slap bar of the trap causing the bells to shake and ring loudly when tripped.

Shotgun surprise!

The shotgun shell trap is another of my favorites, that can be easily setup and provides a very loud warning when activated. They can be built or purchased ready to use out of the box. These can be dangerous so please be careful when using them. ( you may want to use 12 gauge blanks for this)  By placing several of these in the outlying area around your campsite, they provide a great way to know if someone is coming and from what direction they are coming from. They are great for scaring off bears and mountain lions that get too close as well. I strongly recommend that you have at least a few of these in your preps. They are cheap and very effective as early warning devices.


This is the one that you have probably heard me talk about in other post. It uses battery powered motion sensors to detect movement up to about 60 to 80 feet away from the sensor and 300 feet away from the receiver. You can also add multiple sensors to a single receiver for full 360 degree coverage. These are water resistant so the rain and wind won’t hurt them and you can adjust the sensitivity of them to suit your needs. You wouldn’t want it going off every time a small animal scurry’s through, so I would suggest using a Velcro strap to mount them on the side of trees at least 2 feet off the ground.


In the spot light!

Solar powered spotlights with built in motion sensors are another great way to announce the arrival of unwanted guest. By placing these around your camp site and facing them away from your camp, if they are tripped at night, human instinct will cause the intruders to look toward the light thus destroying there night vision at least for a little while and giving you the upper hand in an attack. They would also let you see just what you are up against in the dark. Because they are solar powered, they can be easily charged during the day and used again each night.


Horn of plenty!

This is one that I recently ran across that I thought was interesting. You dig a small hole in the ground and place one of the canned air horns in it and then use a dead fall rock or other flat heavy object to fall on the button and sound the horn. Using a long piece of fishing twine as a trip wire about a foot off of the ground to trigger the alarm seems to be the best setup. When the wire is pulled, the stick falls releasing the dead fall object. These things can wake the dead when they go off, I think. They are extremely loud and can be heard from a long ways from your camp.


Kicking the can!

One more way is to tie a string with empty cans attached to it about a foot off of the ground. Then place a couple of rocks in the cans, to make noise when they are rattled by someone striking the trip wire. This trick is as old as tin cans themselves and was probably used by attaching bells to the wire or string rather than cans earlier in history. In any case the idea is a simple one; it is very effective and can be setup very quickly.

Well, I hope I have given you a few new ideas on how to setup improvised perimeter alarms and made it interesting along the way. If you have any other ideas for making improvised perimeter alarms that are not mentioned here, then please let us know in the comments below so we can share them with others. If you have anything that you would really like to see a post on or simply have any questions, please let me know using the contact link at the top of this page. Until next time, keep on Prepping!


-The Sargent –

Leave a Comment