Arduino is a technology for electronic and robotic hobbits that is easy to use since the software is available for free. This system is best for students with interests in arts, crafts, and experiments, among other things. It encompasses a computer chip on which one can copy applications. The passive infrared sensors detect light emanating from things within the range of their lens view and can be found everywhere today when employed in motion tracking.

What are Passive Infrared Sensors(PIR)?

Passive Infrared sensors(PIR) are electronic devices used to detect motion by measuring variations in infrared (IR) radiation within its surroundings. Used in security systems, and automatic lighting control systems, they are also applicable in many other instances that require motion detection facilities. PIR sensors have some key characteristics:

They are passive because they neither emit energy nor radio waves. A PIR sensor does not emit any radiation, unlike active sensors. Objects around it naturally emit infrared radiation which a PIR sensor can in turn detect. Infrared Radiation: PIR sensors are sensitive to infrared radiation. It is this form of electromagnetic wave with longer wavelengths compared to visible light. They are usually emitted by examples like humans and warm-blooded animals.

Types of PIR Sensors

Here are the different forms of passive infrared sensors: PIR sensors come in a variety of forms and are therefore classified based on their design configurations, applications, as well as the kind of motion they detect. The main types are as follows:

• Single-Pyroelectric Sensor PIR
• Dual-Pyroelectric Sensor PIR
• Ceiling-Mounted PIR
• Wall-Mounted PIR
• Outdoor PIR
• Pet-Immune PIR

Pin Diagram of PIR Sensor

PIR sensor has three pins: Vcc, OUT and GND. Connect these pins of the PIR sensor as follows −

• Connect the +Vcc to +5v of the Arduino board.
• Connect OUT to digital pin of the Arduino board.
• Connect GND with GND pin of the Arduino board.

Pins for PIR Sensor

Working Principle of PIR Sensor

The PIR sensors detect motion based on changes in the infrared radiation around them as they contain two pyroelectric sensors that are sensitive towards the IR radiation. Consequently, the sensors would change if a warm body, like human beings or animals, cross their path which leads to alteration in the amount of infrared radiation observed at these points. This signal is then converted into electricity once it’s identified as an action trigger.

Working of PIR Sensor

Components of PIR Sensor

• PIR Sensor: It is a sensor which tracks the change in heat waves and send the data back to the micro controller for further action. PIR sensor is an responseless sensor which can only track data but can not response to it.
• Lens: Lens is a concave glass which concave all the waves to the center of lens where sensor is places. Lens is responsible to manage the range and angle of vision of the sensor.
• Field of view: It is the area which is covered by the sensor. It is a certain angle with a range.

Code of PIR Sensor

// Defining the pins for the PIR sensor and the LED

const int pirPin = 2; // PIR sensor output pin connected to digital pin 2 of micro controller

const int ledPin = 13; // LED connected to digital pin 13 of micro controller

void setup() {

// Initialize the serial communication at 9600

Serial.begin(9600);

// set the PIR sensor pin

pinMode(pirPin, INPUT);

// set the LED Pin

pinMode(ledPin, OUTPUT);

}

void loop() {

//read data from pir sensor

int pirState = digitalRead(pirPin);

// motion decation code

if (pirState == HIGH) {

// LED on

digitalWrite(ledPin, HIGH);

// Print message

Serial.println(“Motion detected!”);

} else {

// LED off

digitalWrite(ledPin, LOW);

// Print message

Serial.println(“No motion.”);

}

//Wait For 0.1 second

delay(100);

}

Features of PIR Sensors

PIR sensor comes with the list of characteristics or properties, few of them are as follows:

• Wide Working Voltage Range from DC 4.5V to 20V
• Current Drain is less then 60uA
• Detection Angle is greater then 140°
• Detection Distance is from 25 cm to 20 m (can be adjusted)
• Blockade time is 2.5sec (Default)
• Work temperature is between -20 to +80°C

Advantages of PIR Sensors

PIR Sensor has a list of advantages in comparison with other sensors. Few of the main advantages are as follows:

• Small in size
• Wide lens range
• Easy to interface
• Inexpensive
• Low-power
• Easy to use
• Do not wear out

Disadvantages of PIR Sensors

PIR sensor has a few drawbacks as well, few of them are listed below:

• Lower sensitivity
• Less coverage compare to microwave sensors
• Operates in less than equal to 35 degree C
• Have problems in the corner regions
• Insensitive to very slow motion of the objects
• Not very sensitive if the room temperature itself is warm
• Snoozing problem.

Areas of Applications of PIR Sensors

PIR sensors are used in many electronic devices, few of the areas of applications are as follows:

• Home and Business Security Systems
• Automatic Lighting Systems
• Industrial Machinery Monitoring
• Structural Health Monitoring
• Manufacturing Processes
• Transportation Systems
• Aerospace Industry

What is IR Sensor?

IR infrared troubleshooting sensor module based on LM393 IC is a special electronic device used to detect troubles and use simple proximity. IR sensors detect obstacles based on the principle of reflection of infrared light waves. Generally when there is no interference, the infrared receiver will not receive the signal. However when an object comes in front of the sensor, it blocks the infrared light and returns to the sensor. This reflection is then detected by an infrared receiver, indicating interference.

Difference Between PIR and IR Sensor