Fence sensor..

If your fence is "wobbly" enough you could fit a few tremble/tilt type switches - but if it's too wobbly you'll get false alarms (wind, dogs etc.).

Be careful about asking questions about this kind of switch - they can be used as trigger devices, and people may get suspicious. We walk a narrow path!

What kind of fence is it?

yeah, the topmost bar is not wobbly.. the meshed wires below the bar are wobbly. The bar is tubular in shape and runs all around the periphery of the compound. I agree about the tilt switches causing false alarms..

Could have a look at these vibration sensors. No idea if they'd work in this app - but maybe you could make a few phone calls, or track down the manufacturers' website?

try running a single strand of bare copper wire round the top of the fence connected to a covered microswitch. As an additional deterent you can put two parallel wires up about two inches apart in the horizontal plane on top of the fence, wired into an electric fence unit. This system is great at detering crims and the neighbours cat. Otherwise buy a red or blue cattle dog (you can get a cross as well) - the red's can be somewhat vicious if not trained properly while the blue is smaller and more tolerant of children. These dogs are small so good for urban areas and very effective at detering potential thieves

An electric fence is most effectve as long as you are allowed to use it. It's cheaper than feeding a dog too.

Just post a few of these around the fenceline...

Of course it helps if you actually own a gun, but it's not necessary.

yeah, i agree that is neat, but it is an offence here to put such posters around if u dont have that weapon... . nice thought though!

Where are you at that simply posting such a thing would be illegal?!?

Security for these premises provided by the firm of Colt, Remington, Winchester, Smith and Wesson

Plant your borders with cactus or thorn bushes! Get a dog with big teeth that likes to bark! A good German Shepherd works wonders! The dog is very intelligent and protective towards the people who share it's space! Mine is as daft as a brush but has teeth and a bark that could be used in films!

Ah yes, the fur-coated razor blade - very effective!

Look at www.rbtec.com read all you can about MICALERT 103. this is your solution. Your fence must be in good physical conditions. No one will enter without activating the alarm. BUT, it will not stop the intruder. No alarm system will. The one million dollar question is always, You have the alarm, now what? The right to bare arms doesn't give you the right kill the sob. Statistic prove that an EWACS (early warning alarm and countermeasures system) will in 90% of the cases be enough to discourage a none pro such as in your case from advancing further. Inside-home alarms and detection systems, are more often more dangerous than none at all. try to avoid confrontation at all (material's) cost. Microphonics sensor cable is expensive($2000.00/2000' of fence) but is very efficient. Early warning will give you time, and reduce the surprise effect. Exterior lights and a pre recorded msg over a small PA system, are all very effective and cheap.

Wangito.

TDC- Tactical Defense Corp. Santiago Chile.

Yeah you could go all out and put in a high powered blue dye firing water pistol system with automatic tracking too. There are computer programs around which monitor camera images for intruders too

Try anti-climb paint, with the added satisfaction of ruining your intruders clothes!

http://www.protectingyourself.co.uk/using-anti-vandal-paint-other-methods.html

I like Barberry bushes, Takes a while for them to grow but they will earn anything they get. Also a couple of Jackrussel terriers will keep them busy.

Personally I think you should be able to use thieves for garden fertiliser.

Brad

Would not motion detectors suffice to trigger an alarm? Seems like these would be much easier to install and harder to defeat than would vibration or touch sensors on the fence. I use motion detection to trigger a wireless alarm in my bedroom. If the alarm goes off, I grab my laser-sighted .38 special, and go looking for whatever triggered the detector.

Thats a great idea.. ,

But are not these motion detectors suspectable to subtle movements like birds, cats and dogs? I keep one dog who sleeps most of the time, only wake up during feeding time.

Cant depend on him though.

I don't think my detectors are activated by birds, cats, or dogs, but occasionally a deer will wander into the zone and set off the outside detector. No problems with false alarms from the detector inside my shop. If it goes off, I figure it's a human problem that must be eliminated. My understanding is that when a perp sees a laser spot on his chest, he can be convinced to follow instructions. If not, then he will experience the sensation of feeling a hole instead of seeing a spot.

OK sounds nice Skeeter,

What is the brand or model name, part number etc, and application details like?

Its range? coverage etc.

Thanks for your help.

Sorry I don't have the details that you request (detector has been on the garage, covering the driveway, for a bunch of years). If you do a little investigating, I'm sure you can find something to satisfy your requirements. Be sure to cover the sensor that turns the unit off during the day with paint or tape, so the detector will still trigger an alarm during daylight hours.

My outside detector will sense movement at 40 to 50 feet within an arc of approximately 180º.

Some detectors are advertised here...

ProLighting.com

How about the rubber strips you see on doors to detect limbs etc. trapped in them? These are hollow rubber extrusions with contact strips inside that close together if someone presses it. You could run this all around the top of the fence.

Advice that the local police here give is to have a trellis or something similarly weak along the top of the fence so that it does not give sufficient purchase for climbing or will break noisily if someone tries to climb over it.

The safety edge stuff is very good, but not cheap, at around £10/m.

If one were to electrify acoording to agricultural practises, would a loud "eAhhh! WTF?" in the distance be sufficient alert?

Suggestion - Go the cinema and watch "Home alone"

I've often thought of using treacle, - as a non-harming gotcha.

A small pipe with pressure nozzles around the perimeter, to spray
in-wards (to avoid innocent passers by) and triggered by a simple
contact wire as the intruder descends over the fence.
You can switch it off when you're at home and normal hours.

A good head to foot coating of treacle (molasses) eeeekkk.

To be really Mr Nasty you could also keep a few bees.

I think most intruders would rapidly lose interest in stealing.

Hope this works for you. (Sign up: Visit by invitation only.)

jt.

Have a free web page on: http://www.mfnb.at

Forget the sensor, go to a farm supply store and buy an electric fence system to used for livestock. Run the wire across the top of the fence and you won'y have problems with intruders.

How about an infrared beam that interfaces with your alarm system. Some come with two beams to prevent false alarms. Run this parallel to the top of your fence. Intruder breaks the beam and sets of the alarm.

Google DIY home security and there's a site called the "Home Security Store" or something like that. They carry these infrared detectors.

Sorry, but the electric fence doesn't work. (for me)
- or any of the other nasties, e.g razor wire etc.; because:

a) They can be dangerous, for children, etc. and
b) Can easily be circumvented (covered) by mats, coats, etc.

The dye guns, etc, could be effective markers, but again
will not stop them, nor slow them down, and could possible blind!

An alarm itself is not much use; also bodily harm is too risky,
for innocents, and being sued and, you still need to catch him/her!

In the UK the authorities take a very dim view of householders
defending their property. Many owners have been (successfully)
prosecuted for injury, by an offending thief; deservedly or not.
(Any hole, or "trap" of any description can get one into trouble.)

I still think a low cost, non-harming "adhesive" - like treacle is
the best solution. A thief can hardly sue you for supplying food!
Try dipping just your hands in treacle, and see how you feel!

I think treacle (molasses) would do the job nicely?

jt.

I used to be in archaeology, but quit,.. when I realised my life was in ruins.

Did you check out the fiber optic sensors on Global spec, they worked on the greatwall of China, they could probably handle a fence.

Me

Hi,

Thanks for all for the various inputs and insights to this problem. Based on your inputs I think i get the "double eye" LD271 IR transmitter coupled with SHF detector ( all siemens products ) hooked up in the transmissive mode where an interuption beyond the double eye distance would trigger the alarm.

Once again thanks again for your valueble inputs...

Joy to all of u

It should not be a problem during the day. Simply purchase motion detector lights and place them in positions to light the yard when an intruder comes within any adjusted distance. I have seen them sensitive up to one hundred feet. The light always confronts an intruder and brightens up the target for your sights. If you want an alarm, get a two bulb light and in one of the sockets screw in a converter plug that will allow you to plug in a buzzer or bell.

Thats great corneliusvansant,

But will it be immunised to movements of cats and dogs....?

Thanks

Another thought - why not electrify the fence. a farm store has the components, even powered by solar - or just put a notice that it is electified! Those signs are also available at a farm & Tractor store.

The infrared detectors available in hardware stores do a good job and they're easy to interface. In the Philippines, they cost around 1500 pesos which translates to around US$35.

Alternatively, you can use an ultrasonic motion detector that works on the principle of the Doppler effect. It detects movement not presence so it can be prone to false alarms from animals (or maybe even a flying paper plane).

The other device is an ultrasonic radar system. This sends out a pulse of ultrasonic sound and the returning echoes gives the system a radar "picture" of the lawn or area. If something gets into the area, the picture changes and triggers an alarm. You can set it so that it ignores anything smaller than a adult or a child. I saw this once on TV but can't remember the name, unfortunately. Try googling.

Good luck.

Sensors? Two dogs. Put chicken wire around the crocks so they won't be peed on. Or train um to their own pee crocks.