Infrared Thermometer – MLX90614 Interfacing with Arduino

ABOUT THE SENSOR

Description: Melexis’ MLX90614ESF-BAA is an infrared thermometer designed for non-contact temperature sensing. An internal 17-bit ADC and a powerful DSP contribute to the MLX90614’s high accuracy and resolution. It has a huge number of applications including body temperature measurement and movement detection.

The MLX90614 provides two methods of output: PWM and SMBus (i.e. TWI, I²C). The 10-bit PWM output provides a resolution of 0.14°C, while the TWI interface has a resolution of 0.02°C. The MLX90614 is factory calibrated in wide temperature ranges: -40 to 85°C for the ambient temperature and -70 to 382.2°C for the object temperature. The measured value is the average temperature of all objects in the Field Of View of the sensor. The MLX90614 offers a standard accuracy of 0.5°C around room temperatures.

This device comes in an industry standard TO-39 package. We’re carrying the 3V version of this sensor.

Features:

• Small size, low cost
• Easy to integrate
• Factory calibrated in wide temperature range:
  • -40 to +85°C for sensor temperature
  • -70 to +380°C for object temperature
• SMBus compatible digital interface
• Customizable PWM output for continuous reading
• High accuracy of 0.5°C over wide temperature range (0 to +50°C for both Ta and To)
• Measurement resolution of 0.02°C
• Single and dual zone versions
• Simple adaptation for 8 to 16V applications
• Power saving mode
• Different package options for applications and measurements versatility
• Automotive grade

Documents:

DATASHEET OF

Infrared Thermometer – MLX90614

 DataSheet

(clickable image)

PIN CONFIGURATION

SOFTWARE REQUIRED

ARDUINO IDE (for windows)

SCHEMATICS

ARDUINO SOURCE CODE

• /* Melexis MLX90614 infrared non contact temperature sensor
   *
   * connect MLX90614 pin 1 SCL to Arduino pin analog 5
   * connect MLX90614 pin 2 SDA to Arduino pin analog 4
   * connect MLX90614 pin 3 Vdd to Arduino pin +5V
   * connect MLX90614 pin 4 Vss to Arduino pin GND
   solder 100n capacitor between Vdd and Vss
  
   * KHM 2010 /  Martin Nawrath
   * Kunsthochschule fuer Medien Koeln
   * Academy of Media Arts Cologne
   */
  
  #include <i2cmaster.h>
  
  char st1[30];
  
  void setup()
  {
    Serial.begin(115200);
    Serial.println("Melexis MLX90614 temperature Sensor");
  
    PORTC = (1 << PORTC4) | (1 << PORTC5);  //enable internal pullup resistors on i2c ports
  
  }
  void loop()
  {
  
    long int tpl;
  
    tpl=readMLXtemperature(0); // read sensor object temperature
    tpl = tpl *10;
    tpl = tpl / 5;
    tpl=tpl-27315;
    sprintf(st1,"object temp: %03li.%li",tpl/100, abs(tpl %100) );
    Serial.print(st1);
    Serial.print("   ");
  
    tpl=readMLXtemperature(1); // read sensor ambient temperature
    tpl = tpl *10;
    tpl = tpl / 5;
    tpl=tpl-27315;
    sprintf(st1,"ambient temp: %03li.%li",tpl/100, tpl %100 );
    Serial.print(st1);
    Serial.print("   ");
    Serial.println("");
    delay(100);
  
  }
  //****************************************************************
  // read MLX90614 i2c ambient or object temperature
  long int readMLXtemperature(int TaTo) {
      long int lii;
      int dlsb,dmsb,pec;
      int dev = 0x5A<<1;
  
    i2c_init();
    i2c_start_wait(dev+I2C_WRITE);  // set device address and write mode
    if (TaTo) i2c_write(0x06); else i2c_write(0x07);                // or command read object or ambient temperature
  
    i2c_rep_start(dev+I2C_READ);    // set device address and read mode
    dlsb = i2c_readAck();       // read data lsb
    dmsb = i2c_readAck();      // read data msb
    pec = i2c_readNak();
    i2c_stop();
  
    lii=dmsb*0x100+dlsb;
    return(lii);
  }

 GITHUB LIBRARY LINK

 

HAPPY INTERFACING

SHUBHAM GUPTA-TECEX