Infrared Temperature Sensors

Infrared Temperature  Sensor

Infrared (IR) temperature sensors, also known as non-contact temperature sensors or pyrometers, are devices that measure temperature by detecting infrared radiation emitted by an object. Unlike contact-based sensors (like thermocouples or thermistors), IR sensors can measure temperature from a distance, making them ideal for applications where physical contact is impractical or undesirable.

How Infrared Temperature Sensors Work:

Every object with a temperature above absolute zero emits infrared radiation. The amount of infrared radiation emitted by an object increases with temperature. An IR temperature sensor detects this radiation and converts it into an electrical signal, which is then used to calculate the temperature of the object.

Key Characteristics:

Non-contact measurement: Measures temperature without physical contact.

Fast response time: Provides rapid temperature readings.

Wide temperature range: Can measure extreme temperatures, both high and low.

Emissivity: 

The accuracy of an IR sensor depends on the emissivity of the object being measured. Emissivity is the effectiveness of a material in emitting thermal radiation, and it ranges from 0 to 1. Some materials (like shiny metals) have low emissivity and may require compensation or adjustment on the sensor.

Applications:

Industrial processes (e.g., monitoring furnace or kiln temperatures)

Electrical and mechanical diagnostics (e.g., detecting overheating components)

Food safety (e.g., monitoring cooking temperatures)

Medical applications (e.g., forehead thermometers)

Types of Infrared Temperature Sensors:

1. Single-point IR sensors: Measure the temperature at a specific point on the object.

2. Infrared thermographic cameras: Provide a visual representation (thermal image) showing temperature variations across an area.

3. Infrared ear thermometers: Common in medical applications for measuring human body temperature.

Using an Infrared Temperature Sensor with Arduino:

To integrate an IR temperature sensor with an Arduino, a commonly used sensor is the MLX90614, which can measure temperature from a distance and communicate using the I²C protocol.

Components Required:

Arduino board (e.g., Uno)

MLX90614 IR temperature sensor

Jumper wires

Breadboard (optional)

Procedure:

1. Wiring the MLX90614 to Arduino: The MLX90614 uses I²C communication, so you’ll connect it as follows:

VCC: Connect to the 3.3V pin on the Arduino.

GND: Connect to a GND pin on the Arduino.

SDA: Connect to the Arduino's A4 pin (I²C Data).

SCL: Connect to the Arduino's A5 pin (I²C Clock).

2. Install the Required Library:

In the Arduino IDE, go to Sketch > Include Library > Manage Libraries.

Search for the Adafruit MLX90614 library and install it.

3. Arduino Code:

Here’s an example of code to read temperature using the MLX90614 sensor:

#include <Wire.h>

#include <Adafruit_MLX90614.h>

Adafruit_MLX90614 mlx = Adafruit_MLX90614();

void setup() {

  Serial.begin(9600);

  mlx.begin();  // Initialize the sensor

}

void loop() {

  // Read the object and ambient temperature

  float objectTemp = mlx.readObjectTempC();  // Temperature of the object being measured

  float ambientTemp = mlx.readAmbientTempC(); // Temperature of the surroundings

  // Print temperatures to the Serial Monitor

  Serial.print("Object Temperature: ");

  Serial.print(objectTemp);

  Serial.println(" °C");

  Serial.print("Ambient Temperature: ");

  Serial.print(ambientTemp);

  Serial.println(" °C");

  delay(1000);  // Wait 1 second before next reading

}

4. Upload the Code:

Connect your Arduino to your computer.

In the Arduino IDE, select the correct Board and Port under the Tools menu.

Upload the code to your Arduino.

5. Monitor the Temperature:

Open the Serial Monitor to see the temperature readings from the object and ambient environment.

Advantages of Infrared Temperature Sensors:

Non-contact measurement: Ideal for objects that are moving, inaccessible, or very hot.

Quick response: Fast and real-time temperature readings.

Versatility: Can be used in many industrial, medical, and consumer applications.

Challenges:

Emissivity adjustments: Accuracy depends on the object’s emissivity, which may need to be adjusted for reflective surfaces.

Ambient conditions: May be affected by environmental factors like dust or steam, which can interfere with the IR signal.

With this setup, you can measure the temperature of an object or surface from a distance using an infrared sensor and display the results via the Arduino.