Just curious - flashing LEDs on burglar alarms

I asked the alarm engineer the exact same thing today (I thought mine was bust), its basically so people know that its a live alarm and not a dummy one. It will probably change colour if its been activated or tampered with as well.

Dummy... Or that's what the LEDs are supposed to stop the burglar thinking it is a dummy.

As you can get LED flashers for next to nothing even dummy boxes can flash these days.

Don't worry. Burglars will only nick bell boxes with flashing LEDs these days as the non-LED ones are unfashionable.

sponix

I think historically that most alarm systems were nothing more than a box on the wall to act as a deterrent because alarm systems were expensive and hard to fit. Theivs quickly learned about this plan. Then some bright spark had the idea to add flashing lights to indicate that there was actually something inside the box.

Paul

Flashing all the time, you mean? I thought they were intended as a visual indicator that the alarm had been activated (point being that the audible alarm has to stop within X minutes of activation for legal reasons.

David

Yes and no respectively. Ours flashes regardless of activation. I assume it is to warn burglars that, we have an alarm fitted as opposed to neighbours who perhaps have not, resulting in them being an easier target.

Pete

The flashing Xenon beacon (short bright flash) is to indicate the alarm has been activated (the bell times out after a short time) since you left the house.

The flashing LED's were supposed to indicate it was a real alarm rather than a dummy bell box, however most dummy boxes now come with flashing lights so it doesn't really mean anything these days. If you want to add one to yours the module costs about a couple of quid.

You can buy LEDs with the flashing IC and current limiting circuit built in - they are identical in appearance to a 'normal' 5mm type. Simply apply

On some bellboxes, ime the ones that have both a red and a green led (which are visible primarily at night through the strobe diffuser) serve an additional function, in that they indicate the status of the bellbox battery and tamper circuit.

On Tue, 27 Sep 2005 15:22:06 GMT, Lobster scrawled:

That's the strobe and the OP is on about the LED's.

On Tue, 27 Sep 2005 19:29:47 +0100, Will scrawled:

Doesn't matter what colour they are, they generally all indicate the status of the box by different methods regardless of colour.

On Tue, 27 Sep 2005 17:57:48 +0100, Peter Parry scrawled:

New one on me. I think you'll find that most dummy boxes lack LED's unless they are sopecifically requested by the installer etc... although some live boxes have no LED's.

Our "flashguard" has them to indicate powered up and ready.

It would seem a strange distribution of effort to fit a dummy bell box which included a mains supply for a flashing led.

A flashing LED could run for years on a very modest battery.

And longer if that battery was rechargeable and backed up with a small solar panel on top ;-)

T i m

No. Do the calculations.

On Tue, 27 Sep 2005 20:48:54 +0100, "Dave Plowman (News)" scrawled:

That's the general consensus, if you're going to go to the effort of fitting a dummy with LED's you may as well go for the full version or a few extrra quid. The battery powered dummy boxes won't neccesarily flash in sync with the live box anyway.

You don't, they either run off solar panels or a "C" size cell which lasts for about 18 months.