Simple Burglar Alarm for Workshop

[Fergie 307]

You could probably repurpose a car courtesy light switch to work on the door with a relay and big horn for something really simple, although unless you incorporate a latched relay then just shutting the door again would turn it off. And if you do use a latched relay then once activated someone would need to reset it.
Another option is just to get a flashing led, you can get 12v ones or self contained units that work off an AA battery or similar. Some "Alarmed" stickers and that may be enough to persuade them to look elsewhere.

 

[Fergie 307]

Dampdog2013 is an e bay seller who does kits. Both my alarms are based on his box. Alarm input is a 12v DC feed, so can be adapted to work with PIR, switches etc. the siren he does is pretty loud, although I have used his output to fire up a much bigger one through a relay.

 

[Chubber]

Don't forget hinge bolts, inexpensive, supplement your locks.

Internal Sonic 'bombs' on a key/hidden switch delay (like some narrowboat owners have)

Sorry, just seen above.

 

[JoeS]

Dampdog2013 is an e bay seller who does kits. Both my alarms are based on his box. Alarm input is a 12v DC feed, so can be adapted to work with PIR, switches etc. the siren he does is pretty loud, although I have used his output to fire up a much bigger one through a relay.

Great recommendation - I'm going to order the light/siren from him.

Got some great ideas on here and I'm going to put something together with a 12v key switch.

 

[JoeS]

Don't forget hinge bolts, inexpensive, supplement your locks.

Internal Sonic 'bombs' on a key/hidden switch delay (like some narrowboat owners have)

Sorry, just seen above.

Good idea on the hinge bolts - just ordered some - great idea.

 

[Fergie 307]

I would spend a couple of quid on a flashing led. You can wire that into the box and mount it on the outside of the building. That way you have a good visual indication when it's live.

 

[Fergie 307]

You can also modify PIR units by gluing a piece of tube on the dome. Reduces their sensitivity and range so they can be used like a proximity sensor. You can experiment with different sizes and lengths of tube. About 10mm ID and 20mm long range reduced to about 6-8 feet and maybe 10°.
Position somewhere that someone needs to walk past to get to whatever you are protecting. Reduced range means much less likely to have false alarms. Handy in situations where a beam isn't practicable.

 

[Stevekane]

When I first joined this forum a few years ago I posted about a motorcycle alarm bought cheaply from ebay and which is still working perfectly to this day, the make was from memory, Winoma and it is a sophiticated vibration/ movment sensor, it came with a siren and remote control, touching the shed door sets of the siren which runs through a series of whoops and police siren sounds before resetting itself if left alone. Its designed for fitting to a motorbike but I run mine from a bell transformer. In truth the siten is uncomfortable but not extreamly loud, but in the middle of the night, when your trying to creep about burgaling I would think it would make you scarper. The great thing is it does its job before they have smashed there way in.

 

[Fergie 307]

That's why I like the beams and or proximity sensors. Sets it off before they have had a chance.

 

[Dabop]

The shed I mentioned before that I made the alarm up for is my stepfathers (with some VERY nice kit inside) less than two weeks after having it built and moving everything inside, it was (successfully) broken into- by them putting a pipe wrench on the factory doorknob and simply twisting it off!!!
I went digging through my old photos and found the pics he took of his 'upgrades' after I fitted the alarm...

Being the inventive (and rather nitpicking) guy he is, this was his 'security upgrade' to the shed door...

That's shown in the 'open the door' mode- the 5mm thick metal plate slides to the left and is locked by a high security padlock in the closed position- once you get it to that 'open' position, you insert the key in the keyhole to the right, and put 'the handle' into the round hole to unlock the door...

This is what that handle does inside the door...

Yeah- seriously- thats a bloody SHED door...


All hand built, including the locking mechanism for the door- the only thing 'bought' was the key lock itself!!! (plus the entire shed is lined inside with 3mm thick steel plate!!!)

Even trying to take the hinge pins out won't work- as those 'tongues' on the right of the door lock into 'lock holes' on the inside of the door frame when closed... and the sliding tongues on the left do the same on the other side when moved by the handles...

There's an alarm on there as well (but not one on the house- guess he knows his priorities lol)

It would take you an hour to get into it with an anglegrinder...

What can I say- he is a perfectionist in everything he makes...

(After 20 years, they haven't gotten into it once since his 'upgrades' lol)