A burglar alarm is a simple circuit that makes an alarming sound in case a person tries to gain forced or unauthorized entrance into a building or other premises such as hospitals, banks, restaurants, etc. It is a type of security device.
Working Principle of Burglar Alarm
A burglar alarm basically works on the principle of automatic conversion of energy from one form to the other due to variation in parameters such as motion. The burglar alarm circuit typically converts electrical energy into sound energy upon sensing movement.
Construction of a Burglar Alarm
A burglar alarm is an electronic device that is a combination of various active and passive electronic components. The tools and components required for the construction of a burglar alarm include resistances, photodiodes, transistors, speaker, connecting wires, motion sensors, soldering iron, solder wire, flux, glue gun, printed circuit board, capacitor, and power supply. To make a Burglar alarm the components are arranged on the printed circuit board as per the circuit diagram and are fixed in place with the help of solder wire and soldering iron.
Working of Burglar Alarm
The working of a burglar alarm consists of a series of steps. The first step is motion detection. The motion sensors connected to a burglar alarming mechanism are placed on the surface of the premises near the doors and windows. The placement of the motion sensors is required to be done strategically. If an unauthorized person tries to enter the premises, the motion gets sensed, the sensors get triggered and the counting mechanism of the alarm gets activated. For the purpose of motion detection, detectors can also be used along with or in place of sensors. The output of the detectors or sensors is linked to the control panel of the device. The control panel of the device takes the information received by the detectors or sensors and use it to trigger the alarm. The output of the circuit is connected to a bell or a buzzer that takes electrical energy as input and convert it into mechanical or sound energy. This conversion of energy from one form to another produces a loud sound that indicates the presence of an intruder or an unauthorized person. The activation, as well as deactivation of a burglar alarm machine, is controlled by the same control panel. If the deactivating mechanism of the alarm is not activated, the device continues to make alarming sounds. The latest models of burglar alarm devices have the provision to control the activation and deactivation of sound from a distance.