Arduino sketch for contactless IR circuit using Melexis thermopile and ATtiny85.

ATtiny_MLX_Sensor

//INCLUDE REQUIRED LIBRARIES
#include <Adafruit_NeoPixel.h>
#include <TinyWireM.h>
#include <Adafruit_MiniMLX90614.h>
#include <SoftwareSerial.h>

int TINY_SDA   =     0;               //ATtiny SDA pin 5
int TINY_SCL   =     2;              //ATtiny SCL pin 7
int LED_PIN    =     1;              //NEOPIXEL LED ON ATtuny PIN 6
int NUMPIXELS  =     1;              //THE NEOPIXEL LIBRARY NEEDS YOU TO PASS THE NUMBER OF PIXELS AS A FUNCTION ARGUMENT

Adafruit_MiniMLX90614 mlx = Adafruit_MiniMLX90614();

SoftwareSerial mySerial(4, 3); // RX, TX

Adafruit_NeoPixel pixel = Adafruit_NeoPixel(NUMPIXELS, LED_PIN, NEO_GRB + NEO_KHZ800);

int delayval = 50; // DELAY

void setup() {
  mlx.begin();            //INITIALIZE THE MELEXIS SENSOR
  pixel.begin();          //INITIALIZE THE NEOPIXEL
  mySerial.begin(4800);   //INITIALIZE THE SOFTWARE SERIAL
}

void loop() {

  //CREATE VARIABLES TO STORE AMBIENT AND OBJECT TEMPERATURES
  float ambientTemp = mlx.readAmbientTempC();
  float objTemp = mlx.readObjectTempC();

  //CALCULATE THE DIFFERENCE BETWEEN THE TWO
  float diff = ambientTemp - objTemp;

  //UNCOMMENT THE SECTION BELOW FOR DEBUGGING
  /*
  mySerial.print("Object Temp: ");
  mySerial.print(objTemp);
  mySerial.print(" , Ambient Temp: ");
  mySerial.print(ambientTemp);
  mySerial.print("  ,  Difference: ");
  mySerial.println(diff);
 */
 
  if (diff > 2) {
    pixel.setPixelColor(0, pixel.Color(0, 0, 255)); //IF OBJECT IS COLD, SET COLOR TO BLUE
  } else if (diff < -2) {
    pixel.setPixelColor(0, pixel.Color(255, 0, 0)); //IF OBJECT IS HOT, SET COLOR TO RED
  } else {
    pixel.setPixelColor(0, pixel.Color(150, 170, 150)); //REPRESENT AMBIENT TEMP WITH WHITE LIGHT
  }

  pixel.show(); // DISPLAY COLOR ON THE PIXEL

  delay(delayval);

}