PIR Sensor Based Motion Security System Using Arduino

The need for Motion Security Systems nowadays is a serious demand. As the number of theft is increasing day by day, there has to be something that will keep us safe. We are all aware of high-end security systems present in the market not easily accessible to everyone. Therefore, we intend to build a cost-efficient electronic sensing system that has the capability of sensing the motion of intruders and setting off the alarm.

I have designed an interesting and cheap motion sensor-based motion security alarm. This Gadget helps to protect us from thieves. In this project, we are going to use an Arduino Nano, PIR Sensor, an LCD display and some other components. This Project can either be powered with a 9V battery or with a USB cable.

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Principle Behind Motion Security System

This is a basic motion-sensing alarm that detects when someone enters a security area. When an intruder is detected, it activates a siren. Our body generates heat in the form of infrared radiation which is invisible to human eyes. But it can be detected by an infrared sensor. This type of sensor is made up of crystalline material that is Pyroelectric. In this project, we are using PIR Motion Sensor Module as an infrared sensor that generates an electric charge when exposed to heat and sends a signal to the Arduino. According to the level of the infrared radiation in front of the sensor, Arduino displays the status on the LCD and starts buzzing the buzzer and glows the LED.

PIR sensors are more complicated than other sensors as there are multiple variables that affect the sensor’s input and output. PIR sensor has two slots in it, each slot is made of a special material that is sensitive to infrared radiation. The sensor is idle, both slots detect the same amount of IR, the ambient amount radiated from the room or walls or outdoors. When a warm body like a human or animal passes by, it first intercepts one-half of the PIR sensor, which causes a positive differential change between the two halves. When the warm body leaves the sensing area, the reverse happens, whereby the sensor generates a negative differential change.


Circuit Diagram

Motion Security System Circuit Diagram

Components Required

  • Arduino Nano
  • PIR Sensor HC-SR501
  • LDR Sensor (Light Dependent Resistor)
  • 16×2 LCD Display
  • Buzzer
  • Vero Board
  • Wires
  • 9V Battery

Working Principle of Motion Security System

This system works as a low light-activated switch that can measure the exact ambient light level. It can adjust the whole system depending on the ambient light threshold value. For that, we take an LDR for measuring this light level.

When a logic HIGH-level signal is detected at its sensor input terminal, the alarm will trigger. Otherwise stays in the logic LOW-level state.

Passive Infrared Sensors can do this whole process easily and efficiently. When a person passes across the PIR sensor, the motion will be detected by his ambient temperature. By this, effectively controls the switching of the motion security alarm system.

Also, we can see the result of the motion sensor using a 16×2 LCD display. When the PIR sensor is ON, LCD will display that motion is detected. And when nothing is detected, the LCD shows that Motion Stopped.

Application of Motion Security System

  • This motion security system is widely used in homes and offices as an intruder alerting system.
  • It is also used in high-alert areas where trespassing is not allowed.

Advantages of Motion Security System

  • The motion security system is very handy and portable, and thus we can easily carry it from one place to another.
  • Circuit diagram is not so complex and thus can be easily troubleshot.
  • The given system sets off a powerful buzzer, and it is effective as any other alarm system
    available on the market.

Disadvantage of Motion Security System

  • It cannot differentiate between a living thing and a non-living thing. So it is also alarming when there is a non-living obstacle in front of the sensor.
  • The motion alarm system determines the presence of the intruder only and does not determine how many persons are in there actually.
  • The alarm activates only when the person passes through the PIR sensor.

Arduino Code

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