I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?

On 15/01/2004 Mortimer opined:-
What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?

No, but you could probably site them so that they wouldn't 'see' a cat
on the ground. Even a bit of black insulation tape is enough, when
placed across the lens to restrict the field of view of a PIR.

--

Regards,
Harry (M1BYT) (Lap)
http://www.ukradioamateur.org

On Thu, 15 Jan 2004 21:18:09 GMT, Harry Bloomfield
wrote:

On 15/01/2004 Mortimer opined:-
What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?

No, but you could probably site them so that they wouldn't 'see' a cat
on the ground. Even a bit of black insulation tape is enough, when
placed across the lens to restrict the field of view of a PIR.

Sorry, this is rubbish. Pet Immune sensors are readily available, from
RS for one, and they work perfectly well. I fitted several in a house
with an extremely large active cat and never had it trigger them.

Typical specs:

"1 or 2 animals up to 13.4 Kg"
"Pet immunity up to 33 Kg a dog or 4 cats"

--
Niall

Mortimer wrote:
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?

TLC do them, but no idea if they are any good

http://www.tlc-direct.co.uk/Main_Ind...mal/index.html


Jon

I'd love to tell you, I changed one in my mums house to a tlc pet
immune, still trying to get her to test it fully.

On Thu, 15 Jan 2004 21:31:33 -0000, "Jonathan Pearson"
wrote:

Mortimer wrote:
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?

TLC do them, but no idea if they are any good

http://www.tlc-direct.co.uk/Main_Ind...mal/index.html


Jon


Lawrence

usenet at lklyne dt co dt uk

Mortimer wrote:
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?

No, impossible. What "pet proof" PIR's actually do is see the area on just
one plane - horizontal from the sensor. Normal PIR's see on at least three
planes - usually 7 degrees 22 degrees and 35 degrees from horizontal. Some
have more sensitivity and include full 90 degree protection both vertically
and horizontally.

Relying on the fact that your pet will not venture higher than the height of
the unit itself it needs to be positioned at least the cat + tail (!) above
any surface that the cat could get on - and that obviously includes kitchen
worktops.

Now then... problem is that worktops are around three feet high so that
added to the cat + tail is around 5 ft. So, positioned on the wall at 5ft
high your "pet proof" PIR will probably not detect your car BUT it won't
detect anyone less than 5ft in height either and considering that many
burglars are kids you immediately have a problem.

Also consider that burglars do what they do for a living and tend to be
anything but stupid. A quick look through your window will reveal the fact
that your PIR is half way down you wall and is therefore pet proof. The
thief then simply enters the room and stays low.

In my experience pet proof detectors (sometimes called pet alley too) are a
waste of time. They offer minimal protection and should the pet venture any
higher than usual (up against a window for example) then you have a false
alarm.

Consider using alternative type of protection such as perimeter protection u
sing contacts, inertias or vibration detectors. If you don't fancy that or
if it's not feasible then consider a dual tec PIR/microwave which has
sensitivity settings and pet alley on the PIR section.

In article ,
PJO wrote:
Also consider that burglars do what they do for a living and tend to be
anything but stupid. A quick look through your window will reveal the
fact that your PIR is half way down you wall and is therefore pet proof.
The thief then simply enters the room and stays low.

The ones I've got had a choice of lenses and also allowed some adjustment
in the horizontal plane. So they're mounted in the 'conventional' place.
They seemed to cope ok with a cat when I last had one, but she was fairly
old and didn't jump that high. ;-)

--
*Shin: a device for finding furniture in the dark *

Dave Plowman London SW 12
RIP Acorn

The ones I've got had a choice of lenses and also allowed some adjustment
in the horizontal plane. So they're mounted in the 'conventional' place.
They seemed to cope ok with a cat when I last had one, but she was fairly
old and didn't jump that high. ;-)

Yes. I'm familiar with those types of PIR. Problem is that if they're
mounted in the conventional place and a pet alley lens or PCB position is
selected the overall sensitivity is quite poor in relation to a standard
setting/lens. You can't have it all ways. Pet proof always means less
coverage/sensitivity. The other common method is to use multiple pulse
count. Most PIR's have the capability to pulse count to 4 but to be honest
the average person moving at normal speed will only cause the average PIR to
actually trip once or maybe twice at a push so it would be possible to walk
through the room without activating the alarm.

So, it's either per alley dual-tec, perimeter protection or poor protection!

The other line of thought of course is does the kitchen actually need space
protection anyway. Kitchens are notoriously bad for alarms. Cookers, hobs,
hoods fridges and washing machines can all cause false alarms with space
protection whereas perimeter is OK with these. Smaller kitchens, like
bathrooms, suffer from condensation problems and that isn't good for any
sensor. OK, if there's a Hi-fi, TV, PC and a whole load of NEFF appliances
then the area may need protection but if it's just a bog standard kitchen
why bother?! Protect the "house", not "the kitchen"!

On Fri, 16 Jan 2004 13:17:29 -0000, "PJO"
wrote:




In my experience pet proof detectors (sometimes called pet alley too) are a
waste of time. They offer minimal protection and should the pet venture any
higher than usual (up against a window for example) then you have a false
alarm.


I don't think these are the same ones. There was nothing in the
instructions for the ones I installed about positioning them with
regard to animals. The method of operation you describe does not rely
on the weight or size of the animal which is quoted in the spec.

In my installation one is aimed at a flight of stairs, no way the cat
could be on the stairs and not in range of the detector, yet it does
*not* set it off, but a human anywhere in range does.

--
Niall

In my installation one is aimed at a flight of stairs, no way the cat
could be on the stairs and not in range of the detector, yet it does
*not* set it off, but a human anywhere in range does.

That's because the detector has a micro processor to analyse the IR field
and so the detector is "deciding" not to activate when it sees the cat.

What I am saying is that these type of sensors do work but are not fool
proof. If, for instance, your cat gets a fright and charges up the stairs
the detector will "probably" go into alarm. People with a dog anything
bigger than small should also avoid these sensors as the IR field from the
dog could cause an activation as the PIR has to alarm should there be any
possibility of an intruder and a medium to large dog will produce the same
amount of IR energy than a small human (kid).

the simple kind of pet resistant movement sensor uses a special lens to lift
the infra red beam above the level of the animal. fine with dogs that stay
on one level but not cats that can climb.
but the good news is there are now movement detectors (been around about
five years) that allow for one or two cats (or other animals) up to a
certain weight. They need careful siting, usually not permiting the animals
to be closer than 6 feet ie no good positioning them above a table or chair.
They do work and ive fitted a number with no trouble. they are less
sensitive than a normal sensor but do the job.

"PJO" wrote in message
...

Mortimer wrote:
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for
attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?

No, impossible. What "pet proof" PIR's actually do is see the area on just
one plane - horizontal from the sensor. Normal PIR's see on at least three
planes - usually 7 degrees 22 degrees and 35 degrees from horizontal. Some
have more sensitivity and include full 90 degree protection both
vertically
and horizontally.

Relying on the fact that your pet will not venture higher than the height
of
the unit itself it needs to be positioned at least the cat + tail (!)
above
any surface that the cat could get on - and that obviously includes
kitchen
worktops.

Now then... problem is that worktops are around three feet high so that
added to the cat + tail is around 5 ft. So, positioned on the wall at 5ft
high your "pet proof" PIR will probably not detect your car BUT it won't
detect anyone less than 5ft in height either and considering that many
burglars are kids you immediately have a problem.

Also consider that burglars do what they do for a living and tend to be
anything but stupid. A quick look through your window will reveal the fact
that your PIR is half way down you wall and is therefore pet proof. The
thief then simply enters the room and stays low.

In my experience pet proof detectors (sometimes called pet alley too) are
a
waste of time. They offer minimal protection and should the pet venture
any
higher than usual (up against a window for example) then you have a false
alarm.

Consider using alternative type of protection such as perimeter protection
u
sing contacts, inertias or vibration detectors. If you don't fancy that or
if it's not feasible then consider a dual tec PIR/microwave which has
sensitivity settings and pet alley on the PIR section.

(Mortimer) wrote in message . com...
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?


Have a look he-

http://www.pyronix.co.uk/english/pro.../petimmune.htm

and a desciption of how a person crawling along the floor is
differentiated from a pet:-

http://www.pyronix.co.uk/english/pro...mmune_spec.htm

HTH

Neil

Have a look he-

http://www.pyronix.co.uk/english/pro.../petimmune.htm

and a desciption of how a person crawling along the floor is
differentiated from a pet:-


http://www.pyronix.co.uk/english/pro...mmune_spec.htm

Yes, agreed and all very good providing your cat doesn't jump onto a worktop
within range of the PIR! These new technology PIR's are brilliant but are
far from fool proof. Expect false alarms and if you don't get any it'll be a
bonus! In any event use a dual tec unit in a kitchen as I mentioned earlier
and as illustrated on the above pyronix site.

"Mortimer" wrote in message
om...
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?

A dual-tech microwave/infra-red detector that goes by weight immunity is the
best for animals that are prone to jump about on furniture and things.
Pyronix, along with many other makers, have a range of these designs. The
Pyronix are marked with a product number which ends with PI.

"Mortimer" wrote in message
om...
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?


Hi

Few more pointers: always use a dual detection triggered control
panel. Numerous alarm systems without this feature have been fitted,
they frequently lead to repeating false alarms, and the owners give up
using them.

Second be careful where you mount door opening detectors, as door
warping or wind can set them off. They are a big source of false
alarms.

Third cover your desired area with more than one technology. Only when
both detect an intruder do you want the system to go off. Most sensors
are prone to some cause of false alarm or other.

Glass break sensors are useful (not foil strips).

There are burglar identifying paints and burglar trapping smoke bombs,
and of course CCTV if you have money to spend. Note only a high res
colour one is worth having - you cant seriously identify someone off a
junk grade picture.

If you fit all this, make sure youve got locks worth having to start
with. Night latches are mostly hopeless, and 2 lever locks are easy to
open, use 5 levers and more than one locking point.

Finally tamperproof wiring is a bonus to protect against the more
determined attackers, but you dont need this in most cases.

Of course it all costs money, hence the temptation to go for a
cheapass solution. Trouble is, 3 PIRs and a single event tripping
system isnt really a solution.


Regards, NT

Hi

Few more pointers: always use a dual detection triggered control
panel. Numerous alarm systems without this feature have been fitted,
they frequently lead to repeating false alarms, and the owners give up
using them.

I think you mean "Double Knock"?!

Second be careful where you mount door opening detectors, as door
warping or wind can set them off. They are a big source of false
alarms.

Is it? I've never heard of it. The average magnetic contact has an operating
gap in execss of 20mm. Newer ones will stretch to 80mm! That's some warped
door!!! As for wind... I have never known wind to cause a door contact to
operate. That is unless the door is blown open!

Door contacts are usually fitted in the door frame on the opening edge for
ease of wiring but can also be mounted in the head of the frame approx 6
inches from the opening edge. As a general rule the door should open a
maximum of approx 8 inches before the contact operates and the further from
the opening edge the more the door needs to open. On bolt hinged doors the
contact can also be fitted on the jamb edge.

Third cover your desired area with more than one technology. Only when
both detect an intruder do you want the system to go off. Most sensors
are prone to some cause of false alarm or other.

Usine two detectors in parrallel is another idea but is messy. Dual-tec
detectors do the job well.

Glass break sensors are useful (not foil strips).

With respect... glass breaks detectors are useless because the ultra-sonic
sound they rely one (breaking glass) can be caused be many other natural
sources. Fridge motors is a good example! I remember in the early 80's when
these bacame popular. We installed hundreds of them in schools, shops and
the like. Then the kids discovered that if they through milk bottles outside
the window the bloody alarm would activate! No, forget break glass
detectors.

As for window foil. It's outdated by many other forms of setection such as
curtain PIR's etc. You can't even buy the proper foil and blocks these days.

There are burglar identifying paints and burglar trapping smoke bombs,
and of course CCTV if you have money to spend. Note only a high res
colour one is worth having - you cant seriously identify someone off a
junk grade picture.

Smoke bombs eh?! Corr!

Burglar identifying paints?? Don't think so. You've been watching too much
007!

Maybe you mean ID spraying? In which case, as we're on a DIY group, I don't
think it's worth mentioning as the minimum cost of registration and
instalation is around £5k!

Finally tamperproof wiring is a bonus to protect against the more
determined attackers, but you dont need this in most cases.

A/T wiring has been standard since the 60's and is an absolute must. It's
not just there to warn of attack but also to give alert to damaged wiring
etc.

Of course it all costs money, hence the temptation to go for a
cheapass solution. Trouble is, 3 PIRs and a single event tripping
system isnt really a solution.

But it is if it does the job. In my time I have installed thousands of 3 PIR
systems with panels that have no more than a single knoxk circuit. They
rarely false alarms and always activated on intrusion.

I'm not having a pop at you NT. I'm just using your post as an example of
how wrong terminology and poor advice can cause more confusion that it's
worth. We're talking security here and it's not good to give outdated advice
and non-suitable idea's.

"PJO" wrote in message ...
NT wrote:


I'm not having a pop at you NT. I'm just using your post as an example of
how wrong terminology and poor advice can cause more confusion that it's
worth. We're talking security here and it's not good to give outdated advice
and non-suitable idea's.

No worries If I'm wrong keep saying, and together we all learn.



Second be careful where you mount door opening detectors, as door
warping or wind can set them off. They are a big source of false
alarms.

Is it? I've never heard of it. The average magnetic contact has an operating
gap in execss of 20mm. Newer ones will stretch to 80mm! That's some warped
door!!! As for wind... I have never known wind to cause a door contact to
operate. That is unless the door is blown open!

That sounds different to the ones I've had experience with. They didnt
have anything like 20mm to play with, and proved to be useless. They
were affected by warp, wind, you name it. The ones that were
decommissioned were magnets and reed relays. But if things have moved
on, good, I gather they have.


Third cover your desired area with more than one technology. Only when
both detect an intruder do you want the system to go off. Most sensors
are prone to some cause of false alarm or other.

Usine two detectors in parrallel is another idea but is messy. Dual-tec
detectors do the job well.

Yes, this is another way of implementing the above, rather than
implementing it at the control panel. Either way, 2 detection events
by 2 different technologies are needed to avoid false alarms.


Glass break sensors are useful (not foil strips).

With respect... glass breaks detectors are useless because the ultra-sonic
sound they rely one (breaking glass) can be caused be many other natural
sources. Fridge motors is a good example! I remember in the early 80's when
these bacame popular. We installed hundreds of them in schools, shops and
the like. Then the kids discovered that if they through milk bottles outside
the window the bloody alarm would activate! No, forget break glass
detectors.

Youre describing early ones, which were problematic as you say. Things
have moved on. All detectors have false trigger modes, these included.
What you describe is the result of using low tech detectors and using
a control panel that (wrongly) triggers from just one detection event.
If you use them with another detector type, with 2 events being
required for system trigger, you have a sound system. Or just use a
modern glass break detector with proper discrimination.

Here we go:

http://web.raex.com/~colombo/security/secmis9.htm

"Older models were plagued by false alarms. This is because they did
very little filtering and even much less audio processing to tell the
difference between a valid sound and one that is normal to the
environment. More recent designs now use microprocessors to digitize
and process the audio sounds picked up in an environment. This enables
them to discern the difference between the sound of a window breaking
and that of a broken drinking glass."

This explains why modern ones are reliable and effective, and
incorporate the tech you mentioned above:

http://web.raex.com/~colombo/security/secmis10.htm


As for window foil. It's outdated by many other forms of setection such as
curtain PIR's etc. You can't even buy the proper foil and blocks these days.

It is around, just not popular. Google. Also, copper adhesive foil
used in lead window making can be used effectively.

Handbook of Loss Prevention and Crime Prevention,
Butterworth-Heinemann:

"In the past, foil tape was the most common way that security
installers electronically secured window glass. Although it is not as
common today, foil tape is still used by alarm installers who are
skilled enough to work with it. In fact, many of them swear that it
works better than any of the electronic devices--called glass-break
detectors--used by other installers.
"Metallic foil...is widely used to detect glass breakage in show
windows, doors, and transoms. When the glass cracks and breaks the
foil, it interrupts the low voltage electrical circuit and activates
the alarm"

http://web.raex.com/~colombo/security/secmis10.htm

"The presence of foil tape on windows is an automatic sign that a
burglar alarm system is employed on the premises. Most burglars would
rather not break into a facility that has one."


Smoke bombs eh?! Corr!

Yup, they work by disorientating the burglar, and making them realise
they are out of control of the situation. If you have a large valuable
premises, using these by entrances halls stops many burglaries in
their tracks.

The disorientation makes it take a long time to simply get back out of
the building, thus improving odds of arrest, as well as being visible
to passers by.

I did say if you had money to spend: this is not really your usual 2
up 2 down kit


Burglar identifying paints?? Don't think so. You've been watching too much
007!

http://www.screwfix.com/app/sfd/cat/...52567&id=16822

cost £7:49.

There are also more technological ones available, which stain the skin
indelibly, but the simple cheap option above is suited to diy use on
drain pipes etc. They both deter and help catch afterwards.


Finally tamperproof wiring is a bonus to protect against the more
determined attackers, but you dont need this in most cases.

A/T wiring has been standard since the 60's and is an absolute must.

a must? why?

It's
not just there to warn of attack but also to give alert to damaged wiring
etc.

etc?


Of course it all costs money, hence the temptation to go for a
cheapass solution. Trouble is, 3 PIRs and a single event tripping
system isnt really a solution.

But it is if it does the job. In my time I have installed thousands of 3 PIR
systems with panels that have no more than a single knoxk circuit. They
rarely false alarms and always activated on intrusion.

My own experience with PIRs makes that hard to imagine. Perhaps either
youre using PIRs that require 2 events to trigger, or use dual
technology, or else PIRs have suddenly come a long way?

Over to you.


Regards, NT

No worries If I'm wrong keep saying, and together we all learn.

Indeed we all will.

That sounds different to the ones I've had experience with. They didnt
have anything like 20mm to play with, and proved to be useless. They
were affected by warp, wind, you name it. The ones that were
decommissioned were magnets and reed relays. But if things have moved
on, good, I gather they have.

No, basically they're still the same. A reed and a magnet. The operating gap
should always be 20mm minimum. Perhaps some cheaper makes have an
insufficient magnet though.

Some contacts have moved on a little though. ID contacts incorporate a chip
which is directly affected my a magnet. These are usually in 7/16 inch
bullet type contacts and are only suitable for use on ID systems.

Oh and we should all be using ID these days because not only is it much more
secure but it's also very easy and cheap to intall and offers much more
flexibility that conventional systems.

Third cover your desired area with more than one technology. Only when
both detect an intruder do you want the system to go off. Most sensors
are prone to some cause of false alarm or other.

Usine two detectors in parrallel is another idea but is messy. Dual-tec
detectors do the job well.

Yes, this is another way of implementing the above, rather than
implementing it at the control panel. Either way, 2 detection events
by 2 different technologies are needed to avoid false alarms.


Glass break sensors are useful (not foil strips).

With respect... glass breaks detectors are useless because the
ultra-sonic
sound they rely one (breaking glass) can be caused be many other natural
sources. Fridge motors is a good example! I remember in the early 80's
when
these bacame popular. We installed hundreds of them in schools, shops
and
the like. Then the kids discovered that if they through milk bottles
outside
the window the bloody alarm would activate! No, forget break glass
detectors.

Youre describing early ones, which were problematic as you say. Things
have moved on. All detectors have false trigger modes, these included.
What you describe is the result of using low tech detectors and using
a control panel that (wrongly) triggers from just one detection event.
If you use them with another detector type, with 2 events being
required for system trigger, you have a sound system. Or just use a
modern glass break detector with proper discrimination.

Here we go:

http://web.raex.com/~colombo/security/secmis9.htm

No, sorry, can't agree. They are still prone to false alarms. I know any
detector can false but these breakglass detectors are more prone. Put it
this way... they are almosy outlawed in the new ACPO (Association of Chief
Police Officers) policy.


"Older models were plagued by false alarms. This is because they did
very little filtering and even much less audio processing to tell the
difference between a valid sound and one that is normal to the
environment. More recent designs now use microprocessors to digitize
and process the audio sounds picked up in an environment. This enables
them to discern the difference between the sound of a window breaking
and that of a broken drinking glass."

No, still can't agree. My experience says different and I'd avoid them like
th eplague.

As for window foil. It's outdated by many other forms of setection such
as
curtain PIR's etc. You can't even buy the proper foil and blocks these
days.

It is around, just not popular. Google. Also, copper adhesive foil
used in lead window making can be used effectively.

No, what's still around is self adhesive alluminium crap. Proper window foil
was lead and not self adhesive.


Handbook of Loss Prevention and Crime Prevention,
Butterworth-Heinemann:

"In the past, foil tape was the most common way that security
installers electronically secured window glass. Although it is not as
common today, foil tape is still used by alarm installers who are
skilled enough to work with it. In fact, many of them swear that it
works better than any of the electronic devices--called glass-break
detectors--used by other installers.
"Metallic foil...is widely used to detect glass breakage in show
windows, doors, and transoms. When the glass cracks and breaks the
foil, it interrupts the low voltage electrical circuit and activates
the alarm"

And what year was that written? 1904?! Trust me, no alarm company uses foil
these days. OK odd job yes but it's just not used as a general rule. It's
not been in the course syllabus for many years.

"The presence of foil tape on windows is an automatic sign that a
burglar alarm system is employed on the premises. Most burglars would
rather not break into a facility that has one."

And again, when was that writtin? 1906?! It's true of the 70's but today all
premises are secured and foil is long ceased to be used.

Smoke bombs eh?! Corr!

Yup, they work by disorientating the burglar, and making them realise
they are out of control of the situation. If you have a large valuable
premises, using these by entrances halls stops many burglaries in
their tracks.

I was actually being sarcastic. Smoke Bombs as you call them are actually
Smoke Generators. They produce smoke by heating glycol - like a disco smoke
machine - same stuff. They are on standby when the alarm is set and activate
the pump when the alarm activates. The most well known system is Smoke Cloak
but these days theyre are "copies". Smoke Cloak was first shown around 1887.

Yes, they're bloody effective but again, we're on a DIY group here and so
it's unlikely to be of any use. I do though admit to having one installed in
my workshop/garage at home. Expect to pay upwards of £400 for one, maybe
more for a decent one. Refills of glycol are around £20 and you'll need
plenty cos you'll show it off to all your mates!

While on the subject... smoke generators are not up to much after a door or
window is left open as the smoke depletes very quickly. Better machines iave
a sensor which, when the smoke thins out, re-activated the machine to top up
the smoke. For this reason your suggestion of installing them in entrance
halls is a no-no. They're mainly used to secure area's "not yet intruded"
thus making entrance to that area very difficult. Computer rooms in office
buildings are a good example.

Burglar identifying paints?? Don't think so. You've been watching too
much
007!

http://www.screwfix.com/app/sfd/cat/...52567&id=16822

That's anti-clime paint - not identifying paint! So, it marks the burglars
hands black. Does that mean that when I next do an oil change on my car and
end up with black hands I'd better avoid being seen in public?!

There are also more technological ones available, which stain the skin
indelibly, but the simple cheap option above is suited to diy use on
drain pipes etc. They both deter and help catch afterwards.

Deter and prevent yes. Help catch - no. Not at all. A simple wip with a rag
and it's gone.

Finally tamperproof wiring is a bonus to protect against the more
determined attackers, but you dont need this in most cases.
A/T wiring has been standard since the 60's and is an absolute must.

a must? why?

How about when you have someone in your house you don't really know?
Decorator, gas man, daughters boyfriend. Wouldn't you like to know when and
if the PIR's, for example, had had their lids removed?! Or what about when
you nic a cable doing something. Wouldn't you like to know there and then
instead of waiting till you try and set the alarm and then have to wonder
where the cut may be?! How about British Standards which have stipulated A/T
wiring since 1980 when the standard was first introduced!

Or how about someone gettign a ladder up to your bell box, removing the lid
and cuting th ebell feed. Wouldn't it be nice to know?!

etc?

See above

My own experience with PIRs makes that hard to imagine. Perhaps either
youre using PIRs that require 2 events to trigger, or use dual
technology, or else PIRs have suddenly come a long way?

Over to you.

In the last 15 years alarm panels and detectors have moved on so much that
they are now very good. Ducl-tec, pulse count, double knock and ID have all
helped.

Even so, like I said I have installed systems before that which have been
nothing but well behaved. It's down to good engineering practice, common
sense and not buying cheap. In 1990 you could buy a UK made PIR for £6.
£4.50 if you bought 50 or more. I bought none, instead choosing to stick to
the old faithful ones that had been used for years previous. The company who
made the cheap £4.50 PIR's went pop after just two years! Says it all. Buy
cheap and not only will you have to buy twice but you'll have loads of grief
too.

In article ,
N. Thornton wrote:
Second be careful where you mount door opening detectors, as door
warping or wind can set them off. They are a big source of false
alarms.

The standard magnetic switch has to move a fair old way to trigger. It
would be some warping or wind movement that would cause a *properly*
fitted one to trigger.

Third cover your desired area with more than one technology. Only when
both detect an intruder do you want the system to go off. Most sensors
are prone to some cause of false alarm or other.

That was my thinking behind using door and window switches, pressure pads,
and PIRs. I don't think any one solution is the perfect one.

--
*If you try to fail and succeed, which have you done? *

Dave Plowman London SW 12
RIP Acorn

"Dave Plowman" wrote in message
...
In article ,
N. Thornton wrote:
Second be careful where you mount door opening detectors, as door
warping or wind can set them off. They are a big source of false
alarms.

The standard magnetic switch has to move a fair old way to trigger. It
would be some warping or wind movement that would cause a *properly*
fitted one to trigger.

Third cover your desired area with more than one technology. Only when
both detect an intruder do you want the system to go off. Most sensors
are prone to some cause of false alarm or other.

That was my thinking behind using door and window switches, pressure pads,
and PIRs. I don't think any one solution is the perfect one.



The perfect solution is to prevent, as far as possible, your property from
becoming a target in the first place.

"BigWallop" wrote in message ...
"Mortimer" wrote in message
om...
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?


Another approach towards security is to use laminated glass in the
openings big enough for burgers to get in through. They'll have to
bash in numerous imes to get through, each time making a breaking
glass noise. They soon give up, as every glass smashing noise is a
real risk to being caught. Repeated smashing is a dead give away. But
retrofitting this isnt really a cheapie option.


Regards, NT

Another approach towards security is to use laminated glass in the
openings big enough for burgers to get in through. They'll have to
bash in numerous imes to get through, each time making a breaking
glass noise. They soon give up, as every glass smashing noise is a
real risk to being caught. Repeated smashing is a dead give away. But
retrofitting this isnt really a cheapie option.

Yes, a good idea and there is always the option of security film too.

Problem is that if they want to get in a simple large jemmy bar will not
only remove the glass but the whole frame too!

I've mentioned security film there but please be aware that for a proper
result it's not a DIY job. Most first timers mess it up and end up with dull
patches and creases all over the gaff.

On Sat, 17 Jan 2004 11:17:36 -0000, "PJO"
wrote:

I've mentioned security film there but please be aware that for a proper
result it's not a DIY job. Most first timers mess it up and end up with dull
patches and creases all over the gaff.

I remember when my daughter was born 16 years ago I bought some
security film on a roll in Mothercare, and applied it to a low-level
window in our rear patio door - which was plain glass.

You are absolutely right about getting creases - even though I thought
I was taking care! I should have taken a bit more time.

PoP

Sending email to my published email address isn't
guaranteed to reach me.

You are absolutely right about getting creases - even though I thought
I was taking care! I should have taken a bit more time.

Yes, it's a bitch and a half to fit properly.

"N. Thornton" wrote in message
om...
"BigWallop" wrote in message
...
"Mortimer" wrote in message
om...
I wish to install a basic alarm system to protect kitchen back door,
dining room patio doors (both at rear) and front door/hallway
downstairs and just landing upstairs which should be enough for attack
via any bedroom. Only thing is we have two cats 15 and 17 years
old,not overly active but still walk about and have access to all the
house. What sort of alarm system should I go for, PIRs seem simple to
source and install but are there any that ignore cats and only react
to humans?


Another approach towards security is to use laminated glass in the
openings big enough for burgers to get in through. They'll have to
bash in numerous imes to get through, each time making a breaking
glass noise. They soon give up, as every glass smashing noise is a
real risk to being caught. Repeated smashing is a dead give away. But
retrofitting this isnt really a cheapie option.

Regards, NT

External or internal metal bars are cheaper, and are more of a deterrent
because they can be seen from further away.