burglar deterrent - a pseudo burglar alarm with a 'noisy' LED

burglar deterrent elektor november 1984 Every week the local papers carry tales of burglaries and break-ins, sometimes in our own street or neighbourhood. Most of these crimes are the work of the "amateurs" or opportunists of the criminal world and they, unlike their "professional" counterparts, should be quite susceptible to some sort of deterrent, even if it is very simple. A popular ploy has been to mount an empty burglar alarm box on the side of the house but as the number of affordable burglar alarms has increased recently most people are now more likely to fit the full system. The problem then is the large number of alarms falsely crying "wolf, with the result that real burglaries often go unnoticed. The circuit proposed in this article does not give false alarms; in fact it gives no alarm at all. Instead it produces a light signal that will never call out the Police unnecessarily, which in itself is a distinct advantage. burglar deterrent a pseudo burglar alarm with a "nois...