20-09-2012, 03:25 PM
SECURITY SYSTEM USING PIR
SECURITY SYSTEM USING PIR.ppt (Size: 231 KB / Downloads: 94)
Introduction of Embedded system
An Embedded system is a special-purpose computer system designed to perform one or a few dedicated functions, sometimes with real-time computing constraints.
It is usually embedded as part of a complete device including hardware and mechanical parts.
the embedded system is dedicated to specific tasks, design engineers can optimize it, reducing the size and cost of the product, or increasing the reliability and performance.
Physically, embedded systems range from portable devices such as digital watches and MP3 players, to large stationary installations like traffic lights, factory controllers, or the systems controlling nuclear power plants.
Aim of the project:
The main aim the project is to provide security. If any persons enter into the home than automatically PIR senses the person and sends information in the form of SMS through GSM.
GSM network is composed of se:veral functional entities, whose functions and interfaces are defined.
Current scenario:
Now a day there is a lot of burglary happening across the city, the reason behind that is police can’t make out the exact location of burglary for example if burglary is happening inside any area in the city, police will get information after the incident had happened, and then they can’t find out the way the thieves had went.
Now so many alarm system and security systems are emerging in our markets using hi-tech techniques, but in our design we are implementing a home automation and security systems
PIR sensors
A PIR sensor is a passive infrared sensor which controls the switching on/off the lighting load when it detects a moving target.
The built in sensor turns on/off the connected lighting load when it detects motion in the coverage area.
PIR will actually switch off the lights when no one is present and switch it on as soon as somebody enters.
It has different working principle during the day time and the night time.
During the day,the built in photocell sensor saves electricity by deactivating the lighting load connected to the sensor.
During the night the connected lighting load is turned on.
PIR is often known as “pyroelectric”,or “IR motion “sensors.
Working principle of PIR sensor
The PIR sensor senses the motion of a human body by the change in surrounding ambient temperature when a human body passes across.
Then it turns on the lighting load to which is connected.
The lighting load remain on until it senses motion.
Once the motion is seized it switches off the lighting load.
Advantages
Flexibuility of the technique.
It will be applicable during day and night.
It will be secured.
They detect infrared light from several feet/yards away ,depending on how the device is calibrated
PIR sensors have been used turn on a light when it detects human movements.
Disadvantages
Any obstacles in between the sensor & the target will limit the sensor’s coverage area & not give the desired result.
Any kind of moving object will trigger the sensor.
PIR sensors can only receive infrared light and cannot emit it like other types of infrared sensors.
They can be expensive to purchase,install and calibrate as well.