Design And Construction Of PIR Motion Detector Sensor And Alarm Security System

1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The need for having home protection has always been there. But in the recent times, considering a dramatic rise in petty crimes like robbery and theft, the need has been more strongly felt to have a fool proof protection of the belongings and the family members. Home security has come a long way in the last few decades. It was in the hands of a guard who manually provided surveillance during nights in the earlier days, but it was not fool proof as it was only normal for him to have momentary lapse of concentration [1][2].
The guard was also susceptible to sleep at times. It was then that home alarm system based upon electronic circuits were developed which proved to be highly reliable and were appreciated by the people as they were relieved from constant monitoring of their homes [1].
Passive infrared sensor based security system is one of the home security alarm which is also called motion detector: The most common single-technology motion detecting sensor uses passive infrared (PIR) energy to recognize the movement of object, such as a person walking near the door. It is most effective in detecting when the heat mass moves across its field of vision of the sensor[2].
This project proposes a system of that senses object across a sensor, this is achieved with help of a PIR (Passive Infrared) sensor which is the main aim of this work.

1.2 PROBLEM STATEMENT
The need for having a constant home protection has always been there. But in the recent times, considering a dramatic rise in petty crimes like robbery and theft, the need has been more strongly felt to have a fool proof protection of the belongings and the family members. Home security has come a long way in the last few decades. It was in the hands of a guard who manually provided surveillance during nights in the earlier days, but it was not fool proof as it was only normal for him to have momentary lapse of concentration. This device brought solution to this need. It ensures adequate protection against intruders [3].

1.3 AIM AND OBJECTIVE OF THE STUDY
The main aim of this work is to build a PIR motion detector sensor and alarm security system that will trigger an alarm when an object approaches the PIR sensor which triggers an alarm indicating the presence of someone. The objectives of the study are:
i. To alert the user whenever in object or intruder is detected.
ii. To implement the circuit
iii. In increase security in our environment

1.4 SIGNIFICANCE OF THE PROJECT
This device operates with the help of passive infrared sensor which is also called optic or motion sensors. These sensors might be mounted before an entrance to a monitored place [4].
When these optic or motion sensors senses breaking of radiation, they trigger the alarm. Passive infrared sensor based security system has many useful purposes, which is why you can find them in many different types of locations. From supermarkets to airports and many types of large buildings, Passive infrared sensor based security system alerts security personnel even when they are asleep[4].

1.5 APPLICATION OF THE PROJECT
This device not just used for home security. In industrial fields, they are used on assembly lines to keep track of the number of products and to shut down dangerous equipment if a person gets too close. Here are a few other ways this device is used [3][4][[5]:
i. To open and close automatic Doors
ii. To turn on and off automatic water faucets and toilets
iii. To turn on lights when a person enters a room
iv. To control ATM displays
v. At automatic ticket gates
vi. For some parking meters

1.6 SCOPE OF THE PROJECT
Generally, in security systems, infrared or laser transmitters and receivers are used. But these methods are cost effective. This work explains about PIR based security system in which PIR. This saves the power consumption and is low cost. PIR sensor is the short form of Passive Infrared Sensor. The PIR sensors are more complicated than the other sensors as they consist of two slots. These slots are made of a special material which is sensitive to IR. The Fresnel lens is used to see that the two slots of the PIR can see out past some distance. When the sensor is inactive, then the two slots sense the same amount of IR. The ambient amount radiates from the outdoors, walls or room, etc.[5]
When a human body or any animal passes by, then it intercepts the first slot of the PIR sensor. This causes a positive differential change between the two bisects. When a human body leaves the sensing area, the sensor generates a negative differential change between the two bisects. The infrared sensor itself is housed in a hermetically sealed metal to improve humidity/temperature/noise/immunity. There is a window which is made of typically coated silicon material to protect the sensing element [5][6].
This work is based on PIR sensor with an IC that produces alarm. The PIR sensor detects the IR radiations emitted from the humans and it produces a digital output.

1.7 PROBLEM/LIMITATION OF THE PROJECT
This device sensor has some problem:
• It has a limited distance to detect the human/object
• It cannot detect the small objects such as insects.
• The reliability of a PIR sensor may also be affected by rapid environmental changes and direct sunlight. Also, things like a fireplace, and direct wind from an air conditioner or heater. This is because a PIR sensor actually detects changes in infrared energy – specifically, the “heat energy” emitted by normal human skin temperature.

1.8 METHODOLOGY
To achieve the aim and objectives of this work, the following are the steps involved:
i. Study of the previous work on the project so as to improve it efficiency.
ii. Draw a block diagram.
iii. Test for continuity of components and devices,
iv. Design of the system was carried out.
v. Studying of various component used in circuit.
vi. Construction of the system circuit.
vii. Finally, the whole device was cased and final test was carried out.

1.9 PROJECT WORK ORGANISATION
The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:
Chapter one of this work is on the introduction to a Passive infrared sensor based security system. In this chapter, the background, significance, objective limitation and problem of a passive infrared sensor based security system were discussed.
Chapter two is on literature review of a Passive infrared sensor based security system. In this chapter, all the literature pertaining to this work was reviewed.
Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.
Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.
Chapter five is on conclusion, recommendation and references.