Tripwire Alarm: Why You Need One and How to Make It

trip wire

Whether it’s your home or a bug-out shelter, you want to feel safe where you sleep.

A tripwire alarm can give you a sense of security by warning you when danger is near.

Safety at home is a major concern for many families who understand that the future is unknown.

From natural disasters to civil unrest, an emergency could happen at any moment and how you prepare now will have a crucial impact on your ability to survive.

According to a recent survey conducted by Honeywell, more than two-thirds of Americans do not feel totally safe in their own homes.

While some families turn to security systems as a precaution, these intricate hardware and software components can be costly to operate and are not without their limitations.

When it comes to keeping their homes safe, many preppers and survivalists turn to traditional methods.

Tripwire alarms are a type of basic alarm system that acts as a dirt cheap alternative to costly monitored home security systems which can cost upwards of $100 a month or $1,200 a year.

How Tripwire Alarms Work

A traditional tripwire alarm consists of a fairly simple setup. First, a thin wire or line is stretched tight across a pathway, usually a doorframe. The wire, string, or cord should be thin enough so that it cannot be easily seen by an intruder, but strong enough so that it doesn’t snap when someone walks into it.

The tripwire is then connected to an alarm system that automatically triggers when the tripwire is activated. There are some types of modern tripwires that do not use wires at all which can be useful in certain circumstances. Here is a look at some of the most common types of tripwire alarms:

1. Direct Tripwire Alarm

Direct tripwire alarms are the easiest and cheapest type of tripwire alarm to setup.

For this option, you will just need some thin wire or fishing line, as well as a very loud keychain alarm or attack alarm. This classic type of alarm may not be as sophisticated as more modern options, but can work just as efficiently.

Of course, direct tripwire alarms can be slightly inconvenient as they require you to connect the alarm directly to the tripwire, meaning you need to be somewhat close for it to wake you up at night.

2. Laser Tripwire Alarm

With a laser or infrared tripwire alarm, an invisible laser or infrared beam is used instead of a wire or cord. While creating a laser tripwire alarm may seem challenging, it’s certainly not as complex as they make it seem in the movies.

You can actually purchase laser tripwire kits online which makes it easier to setup your alarm system. You can also make your own with a few supplies and a little bit of time. Once installed, a laser tripwire alarm will notify you if it detects movement of people or objects passing through the laser beam.

3. Radio-Frequency Tripwire Alarm

A radio-frequency tripwire alarm is a type of alarm system that uses a remote tripwire alarm to signal that someone is on your property or in your home. With this method, you will need to buy or build a small radio transmitter to activate the tripwire alarm using radio-waves.

Similar to a direct tripwire alarm, a wire is stretched across a walkway, causing the intruder to trip as he passes through it. The main difference between the two is that a radio-frequency tripwire alarm uses a radio transmitter to activate the alarm remotely. This can be highly advantageous if you don’t want to rely on an alarm system that must be directly attached to the wire.

How to Build Tripwire Alarms

There is nothing more important than keeping your family safe, especially when faced with an emergency situation.

You can’t always rely on others to protect your home or its residents, but you can take the proper precautions to create a more secure residence or bug-out shelter. Building your own tripwire alarms is a simple way to keep your home a little safer while providing you with some peace of mind.

Building a Direct Tripwire Alarm

Building a direct tripwire alarm is the most economical option, especially if you plan on setting up multiple alarms around your property. To build a direct tripwire alarm, you will need the following supplies:

  • Roll of thin wire, cord, or fishing line
  • Very loud attack alarm or keychain-style alarm

Start by attaching the attack alarm directly to a tree trunk or pole if your outdoors, or the doorframe if you are setting the tripwire up inside your home. Next, securely tie one end of the wire to the pin of the attack alarm.

Tie the other end of the wire to an opposing tree, pole, or if you are inside the home, the other side of the doorframe. The wire should sit about six inches to one foot off the ground and should be taut, but not taut enough to set off the alarm. Once the intruder walks through the tripwire, it will automatically set the alarm off, hopefully causing the trespasser to leave your property.

Building a Laser Tripwire Alarm

If you want to avoid using an actual wire in your tripwire alarms, laser tripwires work especially well when installed correctly. These alarms can be built for just a few dollars and can act as a standalone system or can be incorporated into a larger do-it-yourself security system.

Building a laser tripwire alarm yourself requires the use of a laser pointer. While most laser pointers you find at the store are safe, avoid looking directly at the laser diode to avoid possible eye damage. To create a laser tripwire alarm, you will need to purchase a few supplies, including:

  • Laser pointer
  • Heat shrink tubing
  • Jumper wires
  • Printed circuit board
  • 3 AA batteries
  • 3 AA battery holders
  • 555 timer IC
  • 3-12-volt buzzer
  • 2 resistors
  • Switch
  • CdS photoresistor

The first step involves assembling the circuit. Set the switch to connect the 3-12-volt buzzer.

The alarm should sound without the laser shining on the photoresistor. When you flip the switch, the alarm should turn off. Reactivate the alarm by shining the laser pointer again at the photoresistor and flipping the switch. Solder all of these pieces together on the printed circuit board.

After mounting the AA batteries in the AA battery holders, the holders should be soldered together with the end leads soldered to the circuit board. Connect the batteries and switch to the circuit board using hot glue.

To set off the alarm, you will need to mount the laser pointer to one side of wall, while the circuit board is mounted to the other. The laser pointer must always be on for the alarm to work. To keep the laser pointer in an on position, tightly tape down the button. Configure each piece so that the laser pointer points directly at the photoresistor.

Once you have both components set up, you will need to arm the alarm by flipping the switch to connect the buzzer. When an intruder walks through the beam, the alarm will instantly sound.

Building a Radio-Frequency Tripwire Alarm

Radio-frequency tripwire alarms are a great option for protecting the perimeter of your property.

Building one of these alarms is fairly easy and inexpensive. For this DIY project, you will need the following supplies:

  • Wireless doorbell
  • Clothespin
  • Metal screws
  • Fishing line
  • Wire

To make a wireless doorbell into an alarm system, you will need to make a few modifications. Remove the housing of the doorbell and locate the main switch. Next, solder a small piece of wire to the terminals on each side of the switch.

The purpose of this is to add an external switch that will allow you to activate the transmitter when the tripwire is pulled. A simple switch can be made from a wooden clothespins and a couple of metal screws. The wires must be wrapped tightly around the screws. When the machine screws touch, it completes the circuit and activates the transmitter.

You will then need to set up the trip wire. Any thin wire will do but should be secured about one foot off the ground and taut between two trees. Fishing line is a great choice as it is fairly strong and difficult to see.

Connect the transmitter and switch to one end of the fishing line and connect that end to a tree. The other end of the line should be connected to a nearby tree. Insert the fishing line between the two screws of the clothespin. Once in place, the tripwire is ready to use.

Using Tripwire Alarms for Protection

Tripwire alarms are a non-lethal way to protect your home and send a signal that an intruder is near.

There are several different types of tripwire alarms that can be made, most using simple materials you can find around your home.

By setting up tripwire alarms around your property, you can help keep your family safe without spending a bundle on costly home security systems.

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