The ‘Squawk’ trip wire perimeter alarm and booby trap simulator Manual

The ‘Squawk’ alarm was originally conceived as a mechanical, perimeter intruder detector alarm and booby-trap simulator, that could be permanently issued to  servicemen  as a part of their ‘Every Day Carry (EDC) in the field.  Since the device is mechanical, it uses a percussion  cap as a noise generator and unlike electronic alarm devices, will still continue work after a Nuclear Electro-Magnetic Pulse (EMP).

Squawk is a third generation device and the earlier two generations use 0.22”  long rifle black powder blank cartridges.  Although these devices  and the  blank cartridges  were approved by the police, they still remained subject to very strict military ammunition regulations, which severely limited their use by the military.  The latest Squawk device has been designed  to meet police firearm regulations and also circumvent military ammunition regulations, by basing it on a toy intended and already approved for use by children !.  It would be a very brass-necked General who tried to claim that a toy, was too dangerous for his troops to own and use !.

The  percussion caps used.

Squawk uses a plastic cap, that can be purchased from most toy shops.  Way back when I was young an Italian company called Edison Giocattoli  used to manufacture plastic percussion caps intended for their range of high quality replica guns. Originally they came in two forms, ‘strip’ and ‘ring’. The strip type  contains 13 shots. The ring type are available as both 8 shot and 12 shot.  All types are sold on a card.  The caps are also available in two loudness levels, 125 db and 140 db, the 140 db type being the loudest.
Warning.  Although the caps are intended for use by children, the 140 db type is LOUD !  It is well above the threshold for pain and therefore should never be fired near the ears.  Likewise they should never be used near the eyes, because the  used cap is usually ejected from the device when fired.  Anyone who who employs booby-trap devices should wear safety glasses and that also includes the ‘hardened military professional”.  You have been warned !. It should also be noted that percussion caps also emit a small pulse of flame and should not be used in gas laden atmospheres.
There are cheaper caps available from other manufacturers, but they can be extremely variable in performance. I have never had a single miss-fire using the Italian caps (see note below).

Plastic strip caps are now getting more difficult to find, but that is not a problems as ring caps can be  cut into individual caps with a sharp knife or scissors.  Always make sure the white disc is still in the bottom of the cap  before use.

Loading the Squawk.

Open the device. Push back the hammer and hold it in place with the thumb. Check the cap has the white disk in it and then push it fully home onto the brass anvil.  With the hammer still pushed back, close the device to hold it there.

How Squawk evolved into it’s present form.

In it’s basic state, it is a ‘pressure off’ activated booby trap mechanism.  You simply load and cock the device, place a small weight on top of it and when that weight is removed, it operates and fires the cap. You can use it like that if you wish. For perimeter alarm purposes it needed modification to be activated by a trip ‘wire’.  In this case, we use an almost invisible nylon line as the trip ‘wire’. Each trip line spool provided in your kit holds about 25 metres of line, so your two alarms can cover an  arc of the perimeter up to 50 metres.
A part of the military doctrine is that trip wire should be capable of bringing down a  running man, which makes the trip wire very easy to detect. On the other hand very sensitive devices can be triggered off by the wind, rain etc and are useless, so we have to look for the compromise, safety and reliability.  This really boils down to the choice of the individual, so sensitivity has to be ‘adjustable’ to suit the perceived needs of the individual. In the case of Squawk sensitivity is determined by the thick ness of the O ring used as a trigger.  So if you want more sensitivity use a thinner one and if you want less sensitivity use a  thicker one.  The internal diameter of the trigger O ring is 7.0mm  and I advise that you start with the 2.0mm thick ones provided (7 x 2 mm).

The safety pin.

There is a gulf of difference between setting up a perimeter alarm during a sunny day and  … trying to do the same thing during a freezing cold thunderstorm, with you hands covered by wet cold mud.  They are  not the ideal  conditions to try and tie knots in an  ‘invisible’ trip line !.  So Squawk was ‘designed’  to be pre-assembled before you go into these conditions and all you have to do is to secure the two ends when deploying it. This allows you to  load, cock  the device in daylight, make it safe until you want to deploy it and that means the device has to have a safety pin !.  The addition of the safety pin allows one to change the normal sequence of setting  a trip wire alarm.  This is achieved by securing the alarm device end first, and then with the safety pin in place, run out the trip line and secure it at the remote end.  This way line adjustment is automatic and one does not have to cut the line, make knots etc, making it totally re-useable.
The safety pin provided with each alarm is longer than required, so that it can be used to ‘make safe’ any of the ‘oppositions devices’, you may encounter.

Trip line tension.

One way of detecting trip wires is to walk forward with a vertical length of piano wire held over the fingers. When it detects a metallic trip wire you can feel a definite ‘ping’ sensation  on your fingers.  Here we are using a nylon line which gives very little feedback, because it has some ‘give’ to it.  To make it even less detectable, leave about a one inch droop at the centre of the line,. This also has the advantage that in the early daylight hours, when dew precipitates on the line, it has a chance to run to the low point and  becomes much less visible to the expert eye.  This condition only lasts for a few minutes as the sun rises.


Camouflage has to match the environment in which the alarm is deployed.  Obviously something that works on a red brick wall, is not going to be ‘invisible’ against sand, or grass. Therefore, camouflage has been left up to the user (or in other words we were not smart enough to come up with a universal solution !). I think the best suggestion is the mini pots of model makers Humbrol paint, where you can choose what you think is going to be the best solution for your application.  Surface finish is not a complete answer because things are detected not only by shine, but also by shape, size, shadow and  silhouette. So scraps of an old face veil can work wonders.  In most case the intruder is working towards us  and devices mounted behind obstacles such as trees would not be seen anyway.

Deploying the Squawk in the field.

The Squawk alarm is a multipurpose device  and can be used in many ways.  For example it can be deployed as a general perimeter intruder detector alarm, or an alarm to warn of intrusion at a tactical ‘choke point’, such as a track, stream, river, road, bridge or gateway.
Using the ‘pressure off’ mode can give warning of interference of specific objects, such as a map left on a track, an empty magazine, or your wallet !. The number of ways you can use Squawk is limited only by your own imagination.
Below is a photo of a Squawk set up in the ‘trip’ wire mode, with the safety pin attached. A cable tie (provided) secures the Squawk to the wooden stake. The safety pin prevents the  trigger O ring from coming off during deployment. Note that the safety pin is inserted between the O ring and the anvil.

When the Squawk is secured at both ends, the safety pin can be removed and the alarm is ‘live’.
When dismantling the alarm, insert the safety pin first !.
You can lose everything apart from the basic device and some caps and it will still work. The photo shows a nylon trip line connected  and  a rock holding the device in place.  The trip line pulls the device out from under the rock and it fires. Very little weight is required,  to hold it in the ‘safe’ condition. Notice that the actual trip line is almost  ‘invisible’.

Nylon line recovery tip. Hardware stores sell wall plugs in  12” lengths and the orange grade makes a nice tight fit in the line spool hole.  A 3” length of this  can act as a spool handle when reeling in the nylon line.

Deploying Squawk in the urban situation.

The urban situation is an open  ‘area’, in which there are some buildings and in those buildings are rooms.  In those rooms are objects which may be large (furniture),  or small objects such as wallets, safes, handbags, clothes, money, weapons, maps etc..

Any object, of any size, within a room, can be  alarmed, it is just that some objects need more thought than others.  All of the items below were ‘ booby trapped’ with Squawks in seconds.

The main points of interest are the access points, such as doors and windows.
Doors and window frames may be made of plastic or wood.  Metal window frames are also still to be found. In all cases,  part of the frame is fixed into the wall and the other part is hinged to open. It is across this gap that we need to apply the Squawk. Let us consider an internal  wooden door frame and how we can install a Squawk onto it.

Since it is my own door, I wanted to do it without any obvious damage, so the device is anchored to the top of the door frame with a drawing pin. A short length of line is fixed to the trigger O ring and fixed to the moving part of the door with a foam sticky pad. To stop the line pulling out of the pad, wrap the line around it a couple of times before applying the pad to the door.  A small duct tape strip would work equally as well. On  plastic doors and frames,  sticky pads, or duct tape can be used on both ends.  
Door handles are an obvious choice for a Squawk application, the downward motion of the handle triggering the Squawk. Here two short lengths of line are used, one tied to the door handle and the other fixed to the door with a sticky pad or duct tape.  When the handle is depressed on the other side of the door, the Squawk fires.

Whether you you use nails, glue, screws, sticky pads, super glue, picture pins, screw eyelets, thumb tacks, tree nails, staples etc to secure the device … the traditional approach, works fine, but a reliable trap takes time and care to set up.  Often too much time in the training situation.
So, we decided to tackle this problem and now it takes less than three seconds  to booby-trap any door, or window, using a Squawk !. Seconds to install it and seconds to take it off !. The means to do this, is included in each  Squawk kit. It can do other things as well, like setting a trap on the rear of a door, from the front of it !. The same ‘invention’ also works on windows,  as well as things like closed draws. The number of applications are limited only by your  imagination !.

Curtains, fabrics and  items of clothing.
Anyone entering a room during a search, is going to want to be able to see what they are doing and if the curtains are closed, a natural reaction is  to open them !.  The same principals  apply, one side of the Squawk is secured to  to something fixed and the other end to the item you wish to booby trap. The curtain can be secured to the Squawk using a safety pin.
Another  example  is if we want to booby trap a beret sitting on a glass top table,  then we could secure one side of the Squawk to the table top with a sticky pad and the other end to the beret with a safety pin. This is the reason the safety pins have been included with the kit.


Under construction.

Remote control of a Squawk.

The Squawk is set up in the target area and the trip line fed out to the remote firing position, where a pull on the line will fire the device.  In the training situation, this allows  ‘command wire’ detection practice in a safe and unrestricted way.  As the nylon line is almost invisible when on the ground,  it will normally not be required to camouflage it, so set-up is quick and simple.  
In operation, secure the Squawk where required, make sure the safety pin is fitted, before reeling out the line to the remote ‘firing’ location.  When everything is ready, remove the safety pin and the device is ‘live’.  The device can be made ‘safe again by refitting the safety pin, while holding the Squawk closed.
There are some ‘interesting’ applications for Squawk in the remote control mode and they may be covered on the Squawk forum (See Forums button on the  Home Page).

© John Magic Kent 2012. All rights reserved.