Introduction: Motion Sensored Security System

This is a security system using an Arduino uno and a PIR motion sensor which triggers an alarm when motion is sensed and is best in securing you house from burglars.This project is useful as, when burglars hear the alarm ring loudly they often run off!

In my project i have used a relay circuit configured to the Arduino so that 12v could be given to the buzzer for a loud buzz!!!

Step 1: The Parts You Will Need

Parts List

  1. An Arduino UNO
  2. A PIR motion Sensor
  3. Jumper pins (male to male and Male to female)
  4. A 3-242V loud buzzer (HYT-3015B)
  5. An Arduino Relay Shield or my Relay Circuit
  6. A 12v battery or Power supply
  7. Some alligator wires (if you prefer not to solder)

Step 2: Making the Relay Cicuit

Parts you will need

  • A relay (SRD-12VDC-SL-C)
  • 10K Resistor
  • IN4007 Rectifier Diode
  • BC548 Transistor


I have given the schematic below for the Relay to work with the Arduino in the word document below and after the circuit is complete you can test it using the Relay test code I made and it is too provided below.

Step 3: Connecting the PIR Motion Sensor to Arduino

Grab some jumper wires and connect the female side to the PIR motion sensor’s VCC, OUT and GND pins. Then connect the male side of VCC to 5v in Arduino, OUT to Digital pin 2 and GND to any GND pin in Arduino.

Step 4: Connecting the Relay Circuit to the Arduino

Connect the wires from the Relay circuit to the Arduino as shown in the picture leaving the Buzzer’s wires only. After that it should be something like this.In my case the buzzer's wires are the green and brown one.

Step 5: Connecting the Buzzer and Powering Up the Project

Connect any one buzzer wires from the Relay circuit to the buzzer's positive wire and the other remaining wire to a 12v positive power source.Then you connect the buzzer's negative wire to the 12v power source's negative wire.

Step 6: Finalizing the Project

After all connections are complete upload the code i have given below to the Arduino and power up the Arduino using a 9v or 12v power supply.

Further improvements
There are many improvements for this project such as adding a 12v LED to the relay while the buzzer is connected and also adding a camera would mean that the Arduino could capture images in light of the burglar or by using a Arduino GSM shield the Arduino Could send the pictures immediately to the house owner.

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