MLX90614 Infrared Thermometer Device
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Weekend at home makes you a moody person. Let’s make a mini-project to cheer up your day. Today we are going to make a contactless infrared thermometer to read body temperature. As a starter, we will be using Arduino to interface with MLX90614 to make this project.
Starter Pack
Of course, if you are new to MLX90614 sensor, visit my MLX90614 Tutorials.
- Box
- Arduino Pro Mini 3.3V 8MHz (Or other)
- MLX90614 Sensor Module
- OLED Display
- Ultrasonic Sensor HC-SR04P (3.3V – 5V)
- TP4056 Charging Module
- Lipo/Li-ion Battery
- Craft Knife
- Wire Stripper
- AWG 26 Wire
- Lens (Optional)
- Buzzer (Active or Passive)
- Switch
- FTDI FT232 USB to TTL
The Design
I got my design idea from hair wax container because throwing them away is kind of a waste. Reusing them to something else is really a great deal. But, I was facing a problem whether the container could fit all the components or not.
So as a hobbyist maker, Autodesk Fusion 360 offers a limited free version of CAD + CAM for your projects. You can unleash your design ideals to your projects. With that, I made all those components into 3D and assembled into the Fusion 360.
I have uploaded my designs at GrabCad. Feel free to use them.
The Circuit
The Codes
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_MLX90614.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>
float voltComp, objVal;
const int echoPin = 12;
const int trigPin = 13;const int buzzer = 11;
Adafruit_MLX90614 mlx = Adafruit_MLX90614();
Adafruit_SSD1306 oled(128, 64, &Wire, −1);
void setup() {
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INTPUT);
pinMode(buzzer, OUTPUT);
if(!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)){
Serial.println(F("SSD1306 allocation failed"));
for(;;);
}
oled.clearDisplay();
oled.setTextColor(WHITE);
oled.setTextSize(3);
oled.setCursor(30, 6);
oled.print("Body");
oled.setCursor(0, 35);
oled.print("Scanner");
oled.display();
mlx.begin();
delay(500);
}
void loop() {
ambVal = ambTemp();
objVal = objTemp();
oled.clearDisplay();
if(distance() <= 6 && objVal >= ambVal +0.2){
if(calibrateTemp() <= 37.5){
oled.setCursor(13, 22);
oled.setTextSize(3);
oled.print(calibrateTemp(), 1);
oled.setTextSize(1);
oled.print(" ");
oled.cp437(true);
oled.write(79);
oled.setTextSize(3);
oled.print("C");
oled.display();
tone(buzzer, 1000, 500);
}
else{
oled.setCursor(13, 22);
oled.setTextSize(3);
oled.print(calibrateTemp(), 1);
oled.setTextSize(1);
oled.print(" ");
oled.cp437(true);
oled.write(79);
oled.setTextSize(3);
oled.print("C");
oled.display();
for(int i = 0; i <= 10; i++){
tone(buzzer, 1000, 300);
delay(500);
noTone(buzzer);
delay(10);
}
}
}
else if(distance() <= 6 && objVal <= ambVal +0.2){
oled.setTextSize(2);
oled.setCursor(22, 4);
oled.print("Bye Bye");
oled.setCursor(22, 25);
oled.print("You Are");
oled.setCursor(22, 45);
oled.print("Dead!!!");
oled.display();
tone(buzzer, 1000, 2000);
}
else{
oled.setTextColor(WHITE);
oled.setTextSize(3);
oled.setCursor(30, 6);
oled.print("Body");
oled.setCursor(0, 35);
oled.print("Scanner"
oled.display();
}
delay(2500);
}float voltComp;
float readAmb, ambCompTemp;
float readObj, objCompTemp;
float tempVal;
float voltValue(){
voltComp = analogRead(A0) * (3.3 / 1023);
return voltComp;
}
float ambTemp(){
redAmb = mlx.readAmbientTempC();
ambCompTemp = readAmb − (voltValue() − 3) * 0.6;
return ambCompTemp;
}
float objTemp(){
redObj = mlx.readObjectTempC();
objCompTemp = readObj − (voltValue() − 3) * 0.6;
return objCompTemp;
}
float calibrateTemp(){
if(ambVal < 33){
tempVal = objVal + 3;
}
else if(ambVal >= 33 && ambVal < 34){
tempVal = objVal + 2;
}
else
tempVal = objVal + 1;
}
return tempVal;
}long duration;
int distanceCM;
int distance(){
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distanceCM = duration * 0.034 / 2;
return distanceCM;
}