Garden shed alarm systems

[Jeremy Nicoll - news posts]

I've recently acquired a garden shed, which is sited about 8 feet away from my house, in an area of garden that is accessible from the street. I'm considering fitting some sort of alarm to it.

All the 'shed alarms' I've seen advertised seem to be very simple devices that one attaches to a shed's inside wall near the door. Some allow an external siren to be fitted on the shed's outside wall. But - as far as I can see - all these have the obvious disadvantage that a yob could pull the siren off the outside of the shed first, and/or break in and pull the whole unit off the inside wall.

I'd rather have a system with eg door contacts (for normal entry/exit to shed), plus internal PIR (for thief detection) and a key/keypad on the inside of the shed, but a siren in a box high up on the side of the house. Quite a few basic DIY house alarms offer that. But unfortunately they tend to have 13A plugtop PSUs that feed the keypad/controller with mains to keep the system going. That may work if such an alarm is installed inside a house with the PSU and keypad hidden inside the house, but if it's in a shed it seems to me that an enterprising thief could just unplug the system inside the shed...

Does anyone know of a cheap (eg less than 100 pounds?) but reliable system that could have the siren high on the house wall, the controller & PSU inside the house, but have detectors and keypad etc in the shed? Perhaps there'd need to be a second keypad for the system inside the house, if only so one could silence any false alarms without going outside. I think I probably want a wired system, unless anyone's prepared to guarantee that a wireless one would always work.

I'm not looking for a whole-house system, as I already have one. I can't add the shed to the existing system and have it armed/disarmed completely independently of the house zones.

[<me9]

Have an extra panel in the house feeding into the main panel. Make sure the cable to the shed zone has a tamper loop within it, perhaps also a second keypad in the shed. TLC (and prolly Screwfix) seem to have bits that would be adequate at under £100.

[Andrew Gabriel]

In a shed, a PIR is likely to be subject to false alarms due to the wide temperature variations in the sun.

What about a wireless system which is installed entirely in the house, except for the sensor in the shed? You would have to arm and disarm from the house.

I wouldn't run alarm cabling outside a house. Besides the obvious tampering issues, it will also become much more suject to spikes during thunder storms.

What about having it on a 24 hour zone, with a secret switch inside the house to bypass the shed sensor?

[Jeremy Nicoll - news posts]

I'd assumed that the rate of change of temperature would be slow enough for that not to matter. After all, normal house rooms with PIRs warm up too.

...making it much less handy for routine use, eg while gardening (eg in the front garden while shed is in the back), I think.

Also, I have bad experience of wireless routers and don't know whether to trust a wireless connection from a shed into the house.

Being what? If someone is tampering with a cable that's clearly a cause for an alarm. The cable would be in conduit under-ground so not all that accessible.

Is that a risk for a buried cable? Does it depend on how far under ground it is? Is electrical interference from storms not also a problem on wireless systems?

Interesting thought.

[Andrew Gabriel]

That's not quite the problem. Firstly depending on shed siting and shading, you could get 50C in there, which a house would never reach (except in the loft). This causes two problems - significant convection currents which can trigger PIRs (well known for doing so in garages after you parked up a car with a hot engine). Secondly, the high temp can cause the electronic components in the sensor to drift which might make the unit either more or less sensitive, or temporarily fail completely.

You might find it works fine. When I've installed alarms, I initially leave the external sounder disconnected. It's not uncommon to get some false alarms from a new installation due to people forgetting about it, or finding a sensor isn't working right or was positioned badly, or there's some other previously unknown source of false triggering. You want to get those all fixed before you have an external sounder attached to wake all the neighbours. After the first false alarm, they'll ignore it, and you don't want to waste that on a trival teething issue.

Well, I must admit I don't use wireless for alarms, but they have got considerably better than they were a few years ago. There's still the issue of a limited range of sensors, tie-in to the panel manufacture, and little chance of replacing a sensor or extending the system after the panel ceases to be a current product.

Yes, and Yes. It can't be underground everywere (e.g. in the shed). You are making the alarm wiring a larger aerial, and therefore more likely to pick up something nasty.

Wireless systems don't care about glitches, and the chance of permanent damage is less.

[fred]

In article , Jeremy Nicoll - news posts writes

My favourite panel is the Scantronic 9651 which is available from

as code SR06195 for 56.20 with the VAT.

At that price you'd struggle to get all the other bit you need for your

100quid but it's a powerful panel that could potentially take over as your in-house panel too.

The main unit is a good sized remote mounted steel box with a good quality remote keypad. Part set is particularly easy to use with four buttons programmable buttons A-D allowing any combination of zones to be set. As appears to be the case with remote keypad panels, extra keypads cost 50quid or more so could you make do with one, just in the house?

My main recommendation is for sensors to discourage entry in to the shed at all (believing that once entry is gained, the game is over).

First would be a good quality electronic shock sensor linked to a local sounder at the shed. A kick sets off the local sounder for a few seconds to discourage a further attack. The panel I mentioned can count a few shocks before sounding the main alarm if required. Texecom Impaq Plus shock sensors are good CPC code SR04710.

Second would be a microwave sensor with a sensitivity set to trigger when anyone passes close to the shed. With this linked to a subtle but noticeable beeper in the shed, any prospective attacker is warned that there is an active system in use and that it has spotted them. Consider

p-44.html (or ). This one has 2 zones and 2 outputs so you can have a core zone in the shed to trigger the main alarm but you'd need to be very careful with sensitivity settings to avoid false alarms if you linked it to a long sounding alarm. I've not used this one but it is a good price.

Lastly would be an absolutely deafening sounder in the shed itself. Elmdene internal sounders are good, CPC code SR02959. Watch out for placement, I had one so loud that it kept retriggering the shock sensor when activated.

Another tip would be to separately fuse any 12V feed to the shed sensors from the main panel.

[cj]

HI Bearing in mind all previous posts you need to consider exactly what you want to do. You can fit a stand alone alarm system to the shed (if 240v is available) and hard wire or radio link this to your house alarm on a 24hr zone. This gives a local alarm either a small sounder or a fully blown Klaxon if you wish and also sets of the house alarm. You can fit sensors to the shed and either radio link or hard wire back to a panel in the house fitting a remote keypad in the shed .A cheaper option is to fit a keyswitch on the shed to disable its sensors. Radio systems are very reliable these days and parts well stocked (Scantronics stopped supplying their 5ooo series last year after 25 years of production).Their latest series has been with us for 10yrs and the earliest models are still available). Radio range varies but expect at least 30m from most systems. As for hard wired and interference Yes it can happen but I have customer with a 20ftx10ft summer house (wooden shed) and 4mts further down the garden a 12ftx10ft shed. The shed has a door contact and Dualtec sensor the summerhouse ,remote keypad door sensor & 2 dualtec devices.Wiring is in std 8 core alarm cable buried aprox 10" in plastic tube running 12m to the panel in the house. System has been running for nearly 4 yrs through thunder storms snow sun (typical NW weather)

3 activations .1 leak in roof drowned sensor, 2&3 attempted break in both times goods recovered due to cctv footage. Whilst I am not disagreeing with previous posts this is only 1 of over 50 customers who I deal with. Most false alarms are due to faulty installation or damage rather than ELP pulses.Thunder however does play havoc with seismic sensors. As for panels as mentioned Scantronics are very good but Texecom (veritas range ) or Guardtec (Eurosec) or even ADE (optima) are a cheaper option giving almost the same quality and reliability. HTH CJ

[<me9]

I can't see any reason why not if protected by tamper zone.

Lightning would be just as likely to affect indoor upstairs wiring.

[<me9]

I wouldn't trust a wireless alarm. Either it could be blocked, causing it not to function when it should, or it would give false alarms with interference. Neither situation is acceptable for an alarm, and there's no way of protecting against it.

[ARWadworth]

"Jeremy Nicoll - news posts" wrote in message news: [e-mail]...

I did.

I used one of the zones on the house alarm for my shed and set that zone to

24 hour mode (panic/fire) or whatever the manual calls it. The shed is then controlled by a seperate switch (I used a key switch) near the back door that shorts out that zone when I want to enter the shed.

I cannot enter the shed without first entering the house if I call at home to pick something from the shed. An outside keyswitch could overcome that.

I also have a second alarm on my shed. This should go off before the main alarm. Have a search for "police and imperial measurements" on this newsgroup for the one and only time this second alarm went off.

Adam

[Huge]

I've replaced all my PIRs with "dual technology" (*) ones after a succession of false alarms due to temperature swings. And stopped using them altogether in the utility room where the boiler is. We haven't (touch wood) had a false alarm in over 2 years since, whereas we were getting 2 or 3 a year.

(* Combined microwave and PIR)

[Huge]

If you have a monitored system, you are obliged to leave it disconnected from the centrral station for 2 weeks after installtion, for this very reason.

[Andrew Gabriel]

Mine are also all dual tech.

I would be concerned about microwaves seeing through a shed wall though. This will cause the anti-masking detection in some dual-techs to trigger. (I had to return a load of Focus ones which had this issue 7 years ago.)

I would also not be surprised if high ambient temperature might cause more problems with the electronics in a dual tech, what with it being roughly twice as complex. OTOH, if it doesn't, then it would be much less likely to false trigger due to looking at a very hot area.

[Huge]

Could be. I took the dual tech one out of the utility room and put reed switches on the back door and window instead, because the huge temperature swings - over

20 degrees C (it's a very old boiler...) were causing problems in there. I would have thought a shed would have similar problems.