Review on Alarm System Design

 History

        In 1852, Edwin Holmes invented the first electric alarm system in Boston. The basic design featured a tripwire that electrically powered a solenoid that struck a gong when it was set off. He started a business with the concept and moved to New York. In 1905, the American Telephone and Telegraph Company purchased the Holmes business. Using the advanced electrical grid that was established in New York, the company linked the personal burglar alarms to police and fire departments. This was the implementations made to the invention of the burglar alarm system made in the year 1852 by Edwin Holmes.

Previous Work

 

 Simple electric circuit for burglar alarm

Breaking the Circuit: the most basic burglar alarm is a simple electric circuit built into an entry way. In any circuit, whether it's powering a flashlight or a computer, electricity only flows when you give it a path between two points of opposite charge. To turn the electricity on or off, you open or close part of the circuit. To open or close a flashlight circuit, you simply throw a switch. In a burglar alarm, the switch detects the act of intrusion opening a door or window, for example. These sorts of alarms are divided into two categories:

• In a closed-circuit system, the electric circuit is closed when the door is shut. This means that as long as the door is closed, electricity can flow from one end of the circuit to the other. But if somebody opens the door, the circuit is opened, and electricity can't flow. This triggers an alarm.

• In an open-circuit system, opening the door closes the circuit, so electricity begins to flow. In this system, the alarm is triggered when the circuit is completed.

There are a number of ways to build this sort of circuit into an entry way. Closed circuits are normally a better choice than open circuits because an intruder can deactivate the open circuit by simply cutting the connected wires.