Luggage/bicycle Security System

While traveling by a train or bus, we generally lock our luggage using a chain-and-lock arrangement. But, still we are under tension, apprehending that somebody may cut the chain and steal our luggage. The Luggage Security System is a simple circuit that generates an alarm when someone tries to cut the luggage chain. No. of ICs used: 1 A BC558 PNP transistor (T1) enables supply to the sound generator chip when the base current starts flowing through it. When the wire (thin enameled copper wire of 30 to 40 SWG, used for winding transformers) loop around the chain is broken by somebody, the base of transistor T1, which was earlier tied to positive rail, gets opened. As a result, transistor T1 gets forward biased to extend the positive supply to the alarm circuit. In idle mode, the power consumption of the circuit is minimum and thus it can be used for hundreds of travel hours. Learning: Application of the tone generator IC UM3561. Application of transistors as switches Brand: Kits'n'spares, Marketed by: Kits'n'spares