Burglar Alarm Sensor Type & Placement...

[Arif110]

Hi all,

Planning on getting a burglar alarm finally. Heard an ex-burglar on Radio 4 finding it funny how many people don't bother getting burglar alarms - until they've been done!

Live in a 4-bed detached house - with at least 30 windows of other properties that can see our property from any side of the house, & vice versa - brilliant for Neighbourhood Watch!

Estate is a new-build Bellway jobbie - nothing overly flash - cars are middle-end.

Three sensor-types that can use:

a) Infra-Red movement detector (standard type). Good cos they would detect any person in the room moving - whether they've entered via window or from door inside.

b) Infra-Red 'curtain' detectors - which you place over window areas - so anything breaking this virtual 'pane' of IR light will trigger the alarm. Here the room remains habitable even with the system armed. I'd never want to do that partcularly - but wonder whether or not there are other advantages to the curtain set-up - assuming entry would only be through the window. Internal downstairs doors are locked at night.

c) Aperture-opening detectors - i.e. reed-magnet devices which you attach to door and frame - triggers when door opened, therefore.


Questions therefore...

1) Would people use both IR and reed-sensors - or is that overkill?

2) Do I need to arm more than just the downstairs? Assuming we don't 'ask' for it - with open windows, etc - is it true burglars generally don't bother with upstairs windows? Would sensors all over upstairs (& actually converted attic too) - be overkill?

3) How about security (laminated) windows to prevent entry in the first place, versus the alarm method? Anyone done this?

4) Have burglars ever been known to break through internal doors? Our new-build ones feel like you could punch through them! I'm used in my parents' house to internal doors being solid wood buggers - but they did that more because the aesthetically 'better' doors happened to be much stronger.

All advice and thoughts gratefully received.

[philthy]

There are loads of different systems about, and usually they can be tailored to your specific needs.
As a start, I would go with contact switches on every external door, and passive infra red/microwaves on covering the ground floor. If you think that it is possible for a burglar to get in through an upstairs window/roof, cover that as well.
Modern wireless kit is very good now, but you will have to keep changing batteries. Wired stuff is very good, but then you have the problem of hiding the wires. Getting somebody to do this for you, will be a significant part of the cost.
I would also recommend an auto dialler, that will phone whatever numbers you programme into it, neighbour across the road perhaps, police (who will probably ignore a recorded message), your mobile etc etc.
Put the sounder box in a very inaccesable place, where the strobe can be seen from a good distance. A good location is where the police will be able to see it, as they enter your road, if they turn out?

If you are really serious about securing your place, get a digital video recorder, and some good cameras, in very good locations. A good location may actually be inside your house, but if it gets a high quality picture of the burglar, at least it will convict him.

Something like this:

[Vee]

Some of the things sound like extra money making add ons to me.
My parents have a sensor in the living room. The only way in and out of the room is from the hallway (there is a sensor there too). So why do they need a sensor in the living room ?
Extra £100 in ADTs pocket !

One recommendation based on my experience, get an extra control panel put upstairs.
If you've armed downstairs at night and the alarm goes off you can check from upstairs what the problem is (whcih sensor(s) activated)

[Arif110]

Thanks guys. Useful pointers - esp on bell-box on back of house,and control panel siting upstairs.

[Meeja]

Arif110 said:

1) Would people use both IR and reed-sensors - or is that overkill?

Not overkill. Would always go for perimiter protection for doors, and a movement sensor inside the room.

Remember that if you rely on internal PIRs to trigger the alarm, then they will already be in by the time the alarm goes off - and thus it gives them a vital few more seconds before anyone who hears the alarm actually bothers to come and take a peek at what is happening.

Also, if you are relying on PIRs only, then your entry route means that when you walk into your entry PIR, that will just start the entry countdown (30 seconds for example) which gives burglar 30 seconds before anything goes off anyway.

With a door sensor AND PIR, if burglar breaks in through a window, and walks into your PIR, then it is instant bells rather than a 30 second delay.

Arif110 said:

2) Do I need to arm more than just the downstairs? Assuming we don't 'ask' for it - with open windows, etc - is it true burglars generally don't bother with upstairs windows? Would sensors all over upstairs (& actually converted attic too) - be overkill?

I would always arm the upstairs to a degree - usually with a PIR on the landing.

Burglars will try and get in through an upstairs window, if they think they can get in relatively un-noticed.

I have seen instances of access through an open upstairs window, with the burglar using "that old wooden ladder" that next door have been meaning to throw in a skip for a couple of years.

Arif110 said:

4) Have burglars ever been known to break through internal doors? Our new-build ones feel like you could punch through them! I'm used in my parents' house to internal doors being solid wood buggers - but they did that more because the aesthetically 'better' doors happened to be much stronger.

Once a burglar is inside the house, a locked internal door is just going to mean more damaged will be caused. Even if it is a sturdy internal door, if it is locked, it means it will just be kicked harder.

Bell box on the rear of the house can be useful - the more neighbours you can attract the better.

PIR sensors - look at using Dual sensors (PIR circuit, and ultrasonic circuit in the same unit) - basically it reduces the chance of false alarms.

I spent years installing these things, so feel qualified to comment!

Hope that helps

Edited by Meeja on Friday 5th September 23:59

[spikeyhead]

Vee said:

Some of the things sound like extra money making add ons to me.
My parents have a sensor in the living room. The only way in and out of the room is from the hallway (there is a sensor there too). So why do they need a sensor in the living room ?
Extra £100 in ADTs pocket

They have a living room with no windows?

[Meeja]

spikeyhead said:

Vee said:

Some of the things sound like extra money making add ons to me.
My parents have a sensor in the living room. The only way in and out of the room is from the hallway (there is a sensor there too). So why do they need a sensor in the living room ?
Extra £100 in ADTs pocket

They have a living room with no windows?

Could be a high-storey flat with no easy access to the windows?

[MonkeyHanger]

Vee said:

So why do they need a sensor in the living room ?
Extra £100 in ADTs pocket !

Erm..i assume the living room has windows?

Mr Scrote could be in through the window, grab whatever he fancies and out again without triggering the alarm....that's why the living room is covered.

However, ADT are not a company i would recommend.

[Arif110]

Thanks Adrian - exactly what I was after!

Any views on Visonic wireless?

[Meeja]

philthy said:

Modern wireless kit is very good now, but you will have to keep changing batteries. Wired stuff is very good, but then you have the problem of hiding the wires. Getting somebody to do this for you, will be a significant part of the cost.

Would always recommend wired over wireless.

Hiding the wires isn't difficult once you know the tricks

Modern systems will also use End Of Line wiring rather than Double Pole.

In simplistic terms this means that you only need two wires for a door reed switch, whilst still giving alarm circuit and tamper circuit protection

A PIR only needs four cables rather than six.

Technically it means you have less cables to run, but in reality it means if you run 6-core and only use 4 of them, the two spare cores can become useful in the future, without having to damage decoration if you extand the system.

philthy said:

I would also recommend an auto dialler, that will phone whatever numbers you programme into it, neighbour across the road perhaps, police (who will probably ignore a recorded message), your mobile etc etc.

Police will not respond to or even acknowledge a recorded message from an auto-dialler.

Only way to get automated police response is to have your system professionally installed, and sign up to a contract with a monitoring centre.

Even then, police response (in some forces) will only happen once the monitoring centre get a "confirmed" signal (Basically the system will have to trip TWO different sensors before the monitoring centre will call the police - If they only see one sensor tripped, there is a possibility of it being a false alarm, and they will only contact nominated keyholders)

If you go down the pro install route, and monitored systems, you are getting into rather sizeable bills.

[Meeja]

Arif110 said:

Thanks Adrian - exactly what I was after!

Any views on Visonic wireless?

I wouldn't recommend wireless.

I realise that wireless technology has improved over the years, but I prefer anything related to security to have no potential weak points - and if it is wireless, it is potentially hackable (albeit difficult)

Also changing the batteries regularly will drive you insane.