Motion Detector using PIR Sensor :: Home Security

             We are very busy/lazy most of the time, due to which there is a chance of the burglar to sneak into your compound(House). In order to identify the suspicious activities like robbing/stealing things in the absence of us in that place, you can implement this simple circuit in our house which can be easily done with basic embedded knowledge.

Simple Description:
             This circuit finds any motion/movement and signals us using the buzzer and LED.

Components Used:

• Transformer(12V output)
• Bridge Rectifier 
• SPDT Switch
• Battery 9V
• 7805 Voltage regulator IC
• 1K ohm Resistor -2
• LED(RED-1,Yellow-1)
• BC547 Transistor
• 5V input Relay
• PIR Sensor
• Buzzer
• Wires
• General Purpose Board

Most of the components are already discussed in the earlier post of Basic Water Tank Overflow Alarm Circuit Components

So let me explain the left out components with simple description below:

PIR Sensor:

PIR - Passive Infra Red 

It is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view.

This sensor detects any infra red radiations which is emitted by animals, humans, etc.

PIR Sensor

PIR Sensor fixed at Entrance of the house or any place which has to be under surveillance

For more details refer Wikipedia :Wiki : PIR Sensor

SPDT Switch:

Single pole Double throw switch has 2 inputs but a single output.

The above switch  is PCB friendly which can be soldered along the PCB.

The middle terminal is taken as output. While the rest of the terminals are taken as inputs(1.Battery Source,2. 12V DC from Bridge Rectifier)

So the circuit is powered either with the battery source or the stepped down source using the SPDT switch.

Circuit Diagram:

Use the below schematic for Soldering the  connections among the components.

Now the circuit after soldering the components looks like,

Motion Detector Circuit after soldering the components

The circuit which is been setup inside the House.

Video :

This Video just shows the working scenario of the Circuit.

So Now we are able to find any movement around the surveillance area(PIR sensor fixed area). Now the house/things are secured :)