Understanding Infrared Sensors

 

 we’ll be discussing the basics of infrared sensors, how they work, and their applications.

Chapter 1: Introduction to Infrared Sensors

·       What is an infrared sensor? An infrared (IR) sensor is an electronic device used to measure and detect infrared radiation in its surrounding environment An IR sensor can measure the heat of an object as well as detects the motion.

·       How does an infrared sensor work? An IR sensor can detect changes in the amount of infrared radiation impinging upon it, which varies depending on the temperature and surface characteristics of the objects in front of the sensor . These types of radiations are invisible to our eyes, which can be detected by an infrared sensor. The emitter is merely an infrared LED (Light Emitting Diode), and the detector is simply an infrared photodiode sensitive to infrared light of the same wavelength as the IR LED. When infrared light strikes a photodiode, IR source (transmitter) is used to emit radiation of required wavelength.

·       This radiation reaches the object and is reflected back.

·       The reflected radiation is detected by the IR receiver.

·       The IR Receiver detected radiation is then further processed based on its intensity. Generally, IR Receiver output is small and amplifiers are used to amplify the detected signal.

·       .

·       Types of infrared sensors There are two types of IR sensors: active and passive. Active IR sensors contain both a transmitter and receiver Examples of Active IR Sensor: Break Beam Sensor, Reflectance Sensor., while passive IR sensors only detect emitted IR radiation Example of Passive IR Sensor: Thermocouple-Thermopile, Bolometer, Pyro-Electric Detector.

The most common IR sensor has a 3-pin connector. The pin configuration is as follows:

VCC: Power Supply +5v

GND: Power Supply Ground

OUTPUT: Active High Output or 5V TTL logic output. In some IR sensors, there will be an analog output which will give you the voltage reading between 0 and 5 V

·        

Chapter 2: Infrared Radiation

·       What is infrared radiation? Infrared radiation - also known as infrared light - refers to electromagnetic radiation that has wavelengths longer than those of visible light ,  region of the electromagnetic radiation spectrum where wavelengths range from about 700 nanometers (nm) to 1 millimeter (mm).

·       Wavelength regions of the infrared spectrum The infrared spectrum is categorized into three regions based on its wavelength: Near Infrared, Mid Infrared, and Far Infrared .

·       Infrared radiation laws Infrared sensors work on three fundamental physics laws: Planck’s Radiation Law, Stephan Boltzmann Law, and Wein’s Displacement Law .

Chapter 3: Infrared Detection System

·       Key elements of an infrared detection system The key elements of an infrared detection system are the IR transmitter, transmission medium, and IR receiver .

·       IR transmitter The IR transmitter acts as a source for IR radiation .

·       Transmission medium The transmission medium provides a passage for the radiation to reach from the IR transmitter to the IR receiver .

·       IR receiver The IR receiver detects the emitted or reflected IR radiation from objects .

 

Chapter 4: Applications of Infrared Sensors

·       Security alarms IR sensors are commonly used in security alarms to detect motion or movement .

·       Automatic lighting IR sensors can also be used in automatic lighting systems to turn lights on or off based on motion detection .

·       Motion detection IR sensors can be used in motion detection systems to detect general movement, but do not give information on who or what moved .

Chapter 5 Code:

void setup()

{

  pinMode(13,INPUT);

  Serial.begin(9600);

}

void loop()

{

  if (digitalRead(13)== LOW)

  {

    Serial.println("high");   

    delay(10);

  }

  else 

  {

    

       Serial.println("low");   

    delay(10);

    

  }

  

}

Chapter 6 explanation:

This code is written in the Arduino programming language and is used to control an Arduino microcontroller. The code consists of two main functions: setup() and loop().

The setup() function is called once when the program starts. In this function, the code sets the pin mode of pin 13 to INPUT using the pinMode() function. This means that pin 13 is configured to read input signals. The Serial.begin(9600) function is also called in the setup() function, which initializes serial communication at a baud rate of 9600.

The loop() function is called repeatedly in an infinite loop. In this function, the code checks the state of pin 13 using the digitalRead() function. If the state of pin 13 is LOW, the code prints “high” to the serial monitor using the Serial.println() function and then waits for 10 milliseconds using the delay() function. If the state of pin 13 is not LOW, the code prints “low” to the serial monitor and then waits for 10 milliseconds.

In summary, this code reads the state of pin 13 and prints “high” or “low” to the serial monitor depending on whether the state of pin 13 is LOW or not. The code also includes a delay of 10 milliseconds between each iteration of the loop to prevent rapid switching between states. This can be useful for debugging or monitoring the state of a digital input pin on an Arduino microcontroller.