Home made alarm system regulations

[i_am_fubar]

With all the regulations coming out, and me not really 100% sure on anything, I figured I should probably ask this.

I'm an electronic engineer (specialising in embeded systems and things), and I have a real urge to make my home security system from scratch, are there any regulations regarding what specifiactions security systems must adhear to, to be installed?

Also, will it effect my insurance costs? :s

Sam.

 

[plugwash]

If you want to get a reduction in insurance for having an alarm you will have to have a proffesionally installed and monitored system. Personally I wouldn't bother, between the installation costs the monitoring costs the extra excuse it gives them to try and get out of making a payout and the small size of the typical reduction in premium it's probablly more trouble than it's worth.

 

[breezer]

agree 100% with plugwash


if you are starting from scratch there are only 3 things you need to have

20 minute bell cut off

good luck
patients to do it

as you are doing it frorm scratch you do not need to comply to any regs waht so ever, (apart form the bell cut off) but for the cost you would be better off buying in everything since its already made for you

idealy the mains should be connected via a fused connection unit

 

[i_am_fubar]

As I said, I want to do it purely because I want to make one... not because I think it'll be cheaper.... etc.

I also want to make it with an unlimited number of sensor inputs so I can have every window/door monitored. Connect it to a computer and CCTV so it logs events and video where events occur. Also things like always on tamper checks on things like the TV (cant be removed without authorisation).

All this as well as several settings, such as downstairs warnings while I'm in bed (if someone enters/exits in the night, local room alarm goes off)

Sam.

 

[breezer]

good luck then, but i am of the opinion you won't do it, nt becuse f your ability, but becuse there is more nvolved than you think to do all that you have said

 

[aptsys]

It wouldn't be very difficult, especially for an embedded systems engineer. I've had to take an alarm panel from concept to validation and verification in my first job as an engineering consultant for one of the major alarm panel manufacturers and it was one of the shorter projects we've had to work on Good luck and have fun - especially wiring up every window

 

[breezer]

especially wiring up every window

you missed a bit

............checks on things like the TV (cant be removed without authorisation).

 

[i_am_fubar]

Ah, all sensors simply transmit a 'all good' or 'sensor activcated' on a repeated loop (thus stopping removal of a sensor disabling the system).

So a door sensor or a TV alarm switch always output the same signal.

If I DO manage one, anyone instrested in the designs?

Sam.

 

[JohnD]

give the PC a UPS and hide it where it can't be stolen or damaged

have some email alerts too, or save images offsite

 

[i_am_fubar]

am considering connecting it to the GSM network too so I can recieve texts from it

And yea, it'll have a UPS.

Sam.

 

[breezer]

If I DO manage one, anyone instrested in the designs?

not really, why try and re invent the wheel

as for how the sensors work it depends on what it is and what panel it is connected to

lets ignore how the sensor picks up in the first place (for ease)

origonaly there was one continious loop, if the loop was broken then an alarm condition is raised

some one realised one single pole loop was not enogh, becuse you can "bridge it" so any thing after the bridge wont be noticed

so they came up with double pole

one pole +ve
the other -ve

bridge the + to -
shorts out alarm condition raised

then some one came up with the idea of making the 2nd loop (-) 24 hour
and so it stayed for quite a number of years

then some one (a lot of people called some one isnt there?) came up with the idea of one loop with a resitor on the end

cut it or bridge it alarm condition is raised

but it still needed a 24 hour loop, so it didnt last long in the intruder alarm industy, but the Fire alarm industry adopted it, and still use it

then some one came up with the idea of 2 resistors
one "end of line" the panel must alaways see this, and a shunt resistor

when a device is closed it shorts the shunt resistor so the panel only sees the end of line resisitor

when the device detects something the panel sees both resistors and an alarm condition is raised

if the panel sees no resistor, be it shorted or cut, the panel goes into tamper (24 hours)

this last method is quite common since it means you can use a 4 core cable to power a detector and monitor its sate, be it normal, alarm or tamper

There have been various other "fads" mostly called biscuits (seriously)

the most popular was ADE's biscuits with 3 wires, followed by Scantronics biscuits with 7 wires (think it was 7)

Scantronic's ones you had to programme it to give it an identity, but it also had an output

ADE's one was easier to use but was limited to 30 biscuits

Both did very well but were considered a bit too complicated for most alarm engineers and now neither are in production and no spares, wichi is a pain because if you do find a sytem with 30 biscuits they could all be on 1, 4 core cable, whcih means a complete re wire

Still want to continue with your idea?

 

[i_am_fubar]

Yup. I enjoy a good electronics challange. Though my inrests is in making an alarm that isn't just a 'safe' or 'tamper' but a way for every sensor to have its own ID value... A lot like some of the Apollo fire sensors, They work on a 2 wire bus, that supplies power AND data for upto 256 devices.

Sam.

 

[breezer]

as i said biscuits did that, but not up to 256.

i dont think you should attempt it, why try and reinvent the wheel?

for a challege, something to do yes, but you really do have a very long way to go, you have got to make something to give each device an id, and make it tiny, the ADE biscuit's working component was about the size of a transistor, i can up load a pic if you want as i found some id biscuits a month ago.

 

[electronicsuk]

as i said biscuits did that, but not up to 256.

i dont think you should attempt it, why try and reinvent the wheel?

for a challege, something to do yes, but you really do have a very long way to go, you have got to make something to give each device an id, and make it tiny, the ADE biscuit's working component was about the size of a transistor, i can up load a pic if you want as i found some id biscuits a month ago.

Breezer, I can see where Sam is coming from. I'm an electrical/electronic engineer and also enjoy building my own projects, even if it does prove to be more difficult and expensive.

What Sam wants to do isn't particularly complicated as far as things go, it should be quite possible to make something similae to the ADE biscuit system with a very basic 8-pin microcontroller and a couple of external components. If he has access to the right equipment then he could make the whole thing surface mount and condense it down to no bigger than a one pence piece.

Furthermore, we're assuming the system will have the necessary electronics housed within each sensor. It doesn't have to be done that way. For example, each room could have a concealed panel housing the control and ID electronics, powering all the sensors in that room and interfacing back to the main computer/panel via RS485. The possibilities really are limitless on a bespoke system.

 

[bernardgreen]

A bespoke system can include some bespoke "intruder deterants" as well as an alarm on their entry.