Thermometer G

With COVID-19 still wreaking havoc globally,  medical device like IR non-contact thermometer. This project is a DIY Thermometer project.  

This project use Ameba RTL8710AF, which then connects to an OLED display to show temperature data obtained from the MLX90615 IR sensor. Pushing the push button not only perform data acquisition and visualization, but also publish the data via MQTT to all subscribers.

Section 1

Casing.  The casing made by 3D printing. The CAD files have uploaded. Just refer to the CAD file. 

Section 2

Circuit. There are 4 hardware are needed. Micro controller (RTL8710AF, third party arduino dev), OLED screen and IR sensor(MLX90615 ), and a small battery. Refer the following connections. (Reference Github, https://github.com/Realtek-AmebaApp/Ameba_Examples/tree/master/RTL8195AM/007_THERMOGUN)

Section 3

Software upload. Install Arduino IDE, go to board manager to install RTL8195 board. Then refer the following code and upload it into the micro controller. (detail instruction, refer to the web, https://www.amebaiot.com/en/ameba-arduino-getting-started/)

        #include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <WiFi.h>
#include <PubSubClient.h>

// Update these with values suitable for your network.

char ssid[] = "yourNetwork";     // your network SSID (name)
char pass[] = "secretPassword";  // your network password

int status  = WL_IDLE_STATUS;    // the Wifi radio's status

char mqttServer[] = "cloud.amebaiot.com";

char clientId[]       = "amebaClientXXX";  // replace XXX with your initial to avoid Client name collision
char clientUser[]     = "Your Username";   // Key in your www.amebaiot.com Username
char clientPass[]     = "Your Password";   // Key in your www.amebaiot.com Password
char publishTopic[]   = "outTopic";
char publishPayload[] = "thermogun ready"; 
char subscribeTopic[] = "inTopic";
char tempstring[]     = {NULL};
char celsius[]        = "*C";
#define pushbutton 2  // push button connected to pin 2

void callback(char* topic, byte* payload, unsigned int length) {
  // handle message arrived
}

WiFiClient wifiClient;
PubSubClient client(mqttServer, 1883, callback, wifiClient);


// MLX90615 Temperature sensor setup
#define MLX90615_I2C_ADDR    0x5B         // factory default address 
#define MLX90615_REG_TEMP_AMBIENT  0x26
#define MLX90615_REG_TEMP_OBJECT  0x27    // 0x27 = 0b00100111, is a command, meaning reading from sensor RAM and read object temperature
float tempdata = 0;

//SSD1306 OLED display setup
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Only 4 pins are needed 
#define OLED_RESET 10  //(RES)
#define OLED_MOSI  11  //(SDA)
#define OLED_DC    12  //(DC)
#define OLED_CLK   13  //(SCL)
#define OLED_CS    17  //(Not Connected)

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT,
  OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);


#define LOGO_HEIGHT   64
#define LOGO_WIDTH    64

char appbar[] = " Ameba              ";
char title[]  = "ThermoGun ";
char spacer[] = "                    ";

static const unsigned char PROGMEM logo_bmp[] =
{
B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,
B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,
B00000000,B01110000,B01110000,B00000000,B00000000,B00000111,B00000111,B00000000,
B00000000,B01110000,B01110000,B00000000,B00000000,B00000111,B00000111,B00000000,
B00000000,B01110000,B01110000,B00000000,B00000000,B00000111,B00000111,B00000000,
B00000000,B01111001,B11110000,B00000000,B00000000,B00000111,B11001111,B00000000,
B00000000,B01111001,B11110000,B00000000,B00000000,B00000111,B11001111,B00000000,
B00000000,B01111101,B11110000,B00000000,B00000000,B00000111,B11011111,B00000000,
B00000000,B01111111,B11110000,B00000000,B00000000,B00000111,B11111111,B00000000,
B00000000,B01111111,B11110000,B00000000,B00000000,B00000111,B11111111,B00000000,
B00000000,B01111111,B11110000,B00000000,B00000000,B00000111,B11111111,B00000000,
B00000000,B00001111,B10000000,B00000000,B00000000,B00000000,B11111000,B00000000,
B00000000,B00001111,B10000000,B00000000,B00000000,B00000000,B11111000,B00000000,
B00000000,B00001111,B10000000,B00000000,B00000000,B00000000,B11111000,B00000000,
B00000000,B00001111,B10000000,B00000000,B00000000,B00000000,B11111000,B00000000,
B00000000,B00001111,B10000000,B00111100,B00011110,B00000000,B11111000,B00000000,
B00000000,B00001111,B11000000,B00111100,B00011110,B00000001,B11111000,B00000000,
B00000000,B00001111,B11100000,B00111100,B00011110,B00000011,B11111000,B00000000,
B00000000,B00001111,B11110000,B00111100,B00011110,B00000111,B11111000,B00000000,
B00000000,B00000111,B11111000,B00011000,B00001100,B00001111,B11110000,B00000000,
B00000000,B00000011,B11111100,B00001000,B00001100,B00011111,B11100000,B00000000,
B00000000,B00000001,B11111110,B00001000,B00001100,B00111111,B11000000,B00000000,
B00000000,B00000000,B11111110,B00001000,B00001100,B00111111,B10000000,B00000000,
B00000000,B00000000,B01111110,B00001000,B00001100,B00111111,B00000000,B00000000,
B00000000,B00000000,B01111110,B00001111,B11111100,B00111111,B00000000,B00000000,
B00000000,B00000000,B01111110,B00000000,B00000000,B00111111,B00000000,B00000000,
B00000000,B00000000,B01111110,B00000000,B00000000,B00111111,B00000000,B00000000,
B00000000,B00000000,B01111110,B00000000,B00000000,B00111111,B00000000,B00000000,
B00000000,B00000000,B01111111,B11110000,B00000111,B11111100,B00000000,B00000000,
B00000000,B00000000,B00111111,B11111000,B00001111,B11111100,B00000000,B00000000,
B00000000,B11111111,B10111111,B11111100,B00011111,B11111101,B11111111,B00000000,
B00000001,B11000000,B00111111,B11111110,B00111111,B11111100,B00000011,B00000000,
B00000001,B10000000,B00111111,B11111111,B00111111,B11111000,B00000001,B10000000,
B00000011,B00011111,B10110000,B11111111,B11111110,B00000001,B11111000,B11000000,
B00000110,B00111111,B00111111,B11111111,B11111110,B00000001,B11111100,B01100000,
B00000110,B01110000,B00111111,B11111111,B11111110,B00000000,B00001110,B01100000,
B00000100,B11100000,B00111111,B11111011,B11101110,B00000000,B00000110,B00100000,
B00000100,B11000111,B10111011,B11111001,B11001110,B00000001,B11110011,B00100000,
B00000100,B10001111,B00110001,B11111000,B10001110,B00000000,B11110011,B00100000,
B00000100,B10011000,B00110001,B11111000,B00001110,B00000000,B00011001,B00100000,
B00000100,B10010001,B10110001,B11111000,B00001110,B00000001,B10001101,B00100000,
B00000100,B10010011,B10110000,B11111000,B00001111,B00000001,B11001101,B00100000,
B00000000,B10010010,B00110000,B11111000,B00001111,B11111000,B01001101,B00000000,
B00000000,B10010010,B00110000,B11111000,B00001111,B11111000,B01001101,B00000000,
B00000000,B00010010,B00000000,B00000000,B00000000,B00000000,B01001100,B00000000,
B00000000,B00010010,B00000000,B00000000,B00000000,B00000000,B01001100,B00000000,
B00000000,B00000010,B00000000,B00000000,B00000000,B00000000,B01000000,B00000000,
B00000000,B00000010,B00000000,B00000000,B00000000,B00000000,B01000000,B00000000,
B00000000,B00000010,B00000000,B00000000,B00000000,B00000000,B01000000,B00000000,
B00111111,B10000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,
B00111001,B11000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,
B00111000,B11000111,B11100000,B10000001,B10000111,B11110011,B11100011,B00001000,
B00011000,B11100110,B00000000,B11000001,B10000001,B11000011,B00000011,B00010000,
B00011000,B11000110,B00000001,B11000001,B10000000,B11000011,B00000011,B00100000,
B00011001,B11000110,B00000001,B11000001,B10000000,B11000011,B00000011,B01000000,
B00011111,B00000110,B00000000,B01100001,B10000000,B11000011,B00000011,B01000000,
B00011011,B00000111,B11000010,B01100001,B10000000,B11000011,B11100011,B11000000,
B00011011,B10000110,B00000011,B11110001,B10000000,B11000011,B00000011,B11100000,
B00011001,B11000110,B00000110,B00110001,B10000000,B11000011,B00000011,B01100000,
B00111001,B11000110,B00000100,B00110001,B10000000,B11000011,B00000011,B00110000,
B00111000,B11100110,B00001000,B00011001,B10000000,B11000011,B00000011,B00111000,
B00011000,B01100111,B11101000,B00011001,B11111000,B10000011,B11100011,B00011000,
B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,
B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000,B00000000 

};


char *dtostrf (double val, signed char width, unsigned char prec, char *sout) {
  char fmt[20];
  sprintf(fmt, "%%%d.%df", width, prec);
  sprintf(sout, fmt, val);
  return sout;
}

float get_temp(){
  
  uint16_t data;

  Wire.beginTransmission(MLX90615_I2C_ADDR);
  Wire.write(MLX90615_REG_TEMP_OBJECT);
  Wire.endTransmission(false); // false is to instruct i2c NOT to send a STOP bit 
  
  Wire.requestFrom(MLX90615_I2C_ADDR, 2); // read 3 bytes of data
  data = Wire.read();       // 1st byte is LSB
  data|= Wire.read() << 8;  // 2nd byte is MSB
  //Wire.read();              // 3rd byte is PEC, which is not of our interest here. This line is just to exhaust i2c buffer
  
//  Serial.println();
//  Serial.print("Data received is: ");
//  Serial.println(data);
//  Serial.println(data,BIN);
  
  return tempdata = data * 0.02 - 273.15; //raw temperateu data requires conversion to celsius
}


void setup() {
  char counter  = 2;

  Serial.begin(9600);
  Wire.begin();
  pinMode(pushbutton,INPUT); // push button on pin 2

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  
  drawbitmap();    // Draw a logo bitmap image
  
  while ( (status != WL_CONNECTED) && (counter > 0) ) {
    // only attempt WiFi connection twice then bypass wifi
    
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:
    status = WiFi.begin(ssid, pass);

    // wait 5 seconds for connection:
    delay(5000);
    counter--;
  }

  if (status != WL_CONNECTED) {
    display.clearDisplay();
    display.setTextSize(2); 
    display.setTextColor(SSD1306_WHITE); 
    display.println(); 
    display.println(F("WiFi fail"));
    display.println(F("Init MQTT"));
    display.display();
  } else {
    display.clearDisplay();
    display.setTextSize(2); 
    display.setTextColor(SSD1306_WHITE); 
    display.println(); 
    display.println(F("WiFi contd"));
    display.println(F("Init MQTT"));
    display.display();
  }

  if (client.connect(clientId, clientUser, clientPass)) {
    client.publish(publishTopic, publishPayload);
    client.subscribe(subscribeTopic);
  }
  //Display ThermGun interface after all init is done
  interface();
}

void loop() {
  
  while(digitalRead(pushbutton)) {
    tempdata = get_temp();
    Serial.print(" Object= ");
    Serial.print(tempdata);
    Serial.println(" *C");
    dtostrf(tempdata,4,2,tempstring);
    strcat(tempstring, celsius);
    client.publish(publishTopic, tempstring);
    interface();
  }
  client.loop();
}


void interface(void) {
  display.clearDisplay();

  display.setTextSize(1);             // Normal 1:1 pixel scale
  display.setTextColor(SSD1306_BLACK, SSD1306_WHITE);        // Draw 'inverse' text
  display.setCursor(0,0);             // Start at top-left corner
  display.println(appbar);
  display.setTextSize(2);
  display.println(title);
  display.setTextSize(1);
  display.println(spacer);
  display.println(); 

//  display.setTextSize(1); 
//  display.setTextColor(SSD1306_WHITE); 
//  display.println(F("Temperature:"));
//  display.println(); 

  display.setTextSize(2);             // Draw 2X-scale text
  display.setTextColor(SSD1306_WHITE);
  display.print(tempdata); 
  display.println(F(" C"));

  display.display();
  delay(1000);
}


void drawbitmap(void) {
  display.clearDisplay();

  display.drawBitmap(
    (display.width()  - LOGO_WIDTH ) / 2,
    (display.height() - LOGO_HEIGHT) / 2,
    logo_bmp, LOGO_WIDTH, LOGO_HEIGHT, 1);
  display.display();
}
    

Section 4

Playing. Download an MQTT app (lot of free apps in both android and ios store) for check the IoT data from thermometer.