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The main use of the security alarm is from the point of view of
safety. Whenever a person enters a restricted area this security alarm will alert the person concerned.


A motion sensor security alarm system is designed to detect an unauthorized entry into a house or area. motion
sensor security alarm systems can be used in residential buildings,
commercial buildings, offices, industries.


Alarm systems are designed to provide cues to make operators
aware of an operational problem, so that mitigation actions can be taken
New technologies are enabling innovative designs of alarm systems
for safety-critical systems. To help better design alarm systems in
advanced control rooms of nuclear power plants (NPPs), recent
researches on alarm system design in the NPP domain are reviewed
from the following aspects:

(1) functions of an alarm system and opportunities and challenges of new

(2) effects of alarm floods and different alarm management methods;

(3) visual, educational institutes and even in military locations.
Many security alarms were designed and published in the Electronics hub. Here is the simple and efficient motion sensor security alarm using the PIR
sensor. Most of the security systems are very expensive. With the help of
this project, an inexpensive security alarm system can be implemented. presentation of alarm information;

(4) evaluation criteria for alarm systems. Through the comprehensive literature review, this article proposes research topics
related to human factors and ergonomics that are worth studying
in advanced alarm systems of NPPs


The design of the motion sensor security alarm system is easy to
understand. There are different components used to design a
motion sensor security alarm system. They are namely
● PIR sensor
● LM 7805 siren IC
● Relay 9V

  • Transistor NPN BC547
  • Resistors R1(1K ohm)
  • Buzzer – 1s


Instead of infrared or laser transmitters and receivers, PIR (Passive Infrared Radial) sensors are used in this circuit. The sensor is basically a pyroelectric device. When the device is exposed to
infrared radiation, it generates an electric charge. The device is made of
crystalline material. According to the change in the amount of infrared
striking the element, there will be a change in the voltages generated,
which is measured by an on-board amplifier. The infrared light explained here refers to the light radiating from all objects in its field of view. The reason for not having a transmitter and receiver is that the device does not emit one, but only accepts the energy emitted from objects above absolute zero in the form of radiations. Thus the temperature will be different for a human working past a sensor, and that of a wall right in front of it. Thus the word “passive” is used in PIR to explain that it does not emit a radiation and receive it, but instead accepts the incoming infrared radiation passively. When any human is detected, this PIR sensor outputs a logic high value i.e. voltage of 3.5v to 5v. This voltage is applied as input to the siren generator IC. The siren generator has an oscillator internally, to produce the sound. Thus oscillations along with selected tone are sent to the address counter. The address counter then sends the data to the ROM. ROM
then sends the tone on the output pin 3. The output is given to the NPN
transistor to amplify the siren. Thus sound produced can be heard from the
speaker when human is detected.


Whenever anyone enters the restricted area the IR rays released
by the person is sensed by the PIR sensor and it triggers the system and
the alarm starts buzzing. This indicates the concerned person that there is
someone in the concerned place.


A security alarm is a system designed to detect intrusion – unauthorized entry – into a building or other area. Security alarms are used in residential, commercial, industrial, and military properties for protection against burglary, as well as personal protection against intruders. Security alarms in residential areas show a correlation with decreased theft. Car alarms
likewise help protect vehicles and their contents. Prisons also use security systems for control of inmates Some alarm systems serve a single purpose of burglary protection; combination systems provide both fire and intrusion protection. Intrusion alarm systems may also be combined with closedcircuit television surveillance (CCTV) systems to automatically record the activities of intruders, and may interface to access control systems for electrically locked doors. Systems range from small, selfcontained noisemakers, to complicated, multirally systems with computer monitoring and control. It may even include two-way voice, which allows communication between the panel and Monitoring station.


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