Contactless IoT Thermometer

Introduction

The COVID-19 pandemic has spread to most parts of the world like a wildfire. One of the most telling symptoms of the infection includes fever, dry cough, and breathlessness. Now, 95% of cases of the virus have mild symptoms that can be treated and handled at home with proper quarantine precautions. For people who have mild symptoms or are still asymptomatic but fear having been in contact with the virus, the advice given by doctors is that they need to measure their temperature at least twice a day and monitor it to help determine if they are getting better or worse.

The thermometer is the most accurate way to tell if you are running a fever or not. An infrared thermometer can give you the temperature instantly. You can find a contactless infrared thermometer in the online markets but no one supports IoT functionality so keeping the record of the temperature is not easy. To solve this problem I made this IoT thermometer which sends the data to the cloud server automatically when measured and the graph can be visualized from the web dashboard.

Dashboard Graph from Adafruit.io

Features:

• 1. Contactless
• 2. Rechargeable
• 3. WiFi Enabled and store the data to the cloud
• 4. Data can be visualized from a graph
• 5. Auto power-saving mode
• 6. Dual scale and configurable

Video Demo

Step 1: 3D Designing & Printing

After collecting the components you need to print the 3D files. All the required files are attached here. The original design was collected from Thingiverse (https://www.thingiverse.com/thing:4298489). Thanks to Mr. ASHISH PARDESHI for his nice design. I modified the design using Tinkercad. The original design was made for 9V battery, I modified it for 18650 Li-ion rechargeable battery.

I printed all the files using my Anet A8 3D printer I bought from Gearbest.com before 3 years ago. It is an excellent 3D printer at a low cost.

Step 2: Making Display & Control Board

After printing all the files the first work is to prepare the control board with the display. I first soldered three mini tactile buttons for configuration and setting functionality. A perf board should be cut according to the size of the front panel which is (28mm X 48mm). Then according to the button cut solder the buttons. No pull up resistor is required because the internal pull-up resistor will be used from the program. One terminal of all the switches should be connected together which needs to be connected to the ground on a later step.

Step 3: Connecting the Display & Trigger Button

After connecting the buttons the next work is to place the display on the perf board. A separate perf board was prepared for placing the Wemos D1 board into it using female pin headers. display cable and the jumpers from the button boards need to be connected to the female headers according to the schematic. Then we need to connect another button to the board which will be used to measure and upload the data to the cloud.

Step 4: Connecting Battery Spring

We are going to use a 18650 Li-ion rechargeable battery for our thermometer. We will place the battery inside the handle of the thermometer. As we are not using an external battery case for our battery we need to place two battery spring inside the room of the battery. The springs need to be connected to a battery charger circuit through the jumper wires. The battery management circuit helps to charge and protects the battery from overcharging and protects the battery from burning.

Step 5: Placing the Battery Charger Circuit

After connecting the charger circuit to the battery spring using jumper wires the next work is to place the battery charger circuit to the right place. The figure shows the placing of the charger circuit to the right place. It also shows the placing of the spring and the wires.

Step 6: Connecting the Power Wires

To power, wires should bring out from the charger circuit to the controller circuit. Charger circuit has the OUT + and OUT - marking which will be used to provide the power to the controller board.

Step 7: Connecting Power Switch

The battery was placed to the bottom part of the case. A power button will be placed to the top part of the case. The top part has a place for fixing the power switch. An SPDT switch is placed to the top part and connected with the battery out. This switch will be used to turn on and off the device.

Step 8: Configuring & Uploading Arduino Sketch

All the soldering is completed. Now it is the right time to place and fixed all the PCB and sensor to the right part. The front panel board should be fixed with the front side of the printed part. I used hot glue to fix it tightly with the printed plate. The sensor should be placed in the front panel and should be fixed using glue. After placing all the parts we need to upload the sketch and test everything is working.

Before uploading the code you need to prepare your Adafruit IO account. Read this guide if you are new. https://learn.adafruit.com/welcome-to-adafruit-io/...

/* This code works with MLX90614 (GY906) and OLED screen
* It measures both ambient and object temperature in Fahrenheit and display it on the screen
*
*
*
*/
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Fonts/FreeSerif12pt7b.h>
#include <Fonts/FreeMono9pt7b.h>
#include <Fonts/FreeSerif9pt7b.h>
#include <Adafruit_MLX90614.h>
#include "AdafruitIO_WiFi.h"
#include <EEPROM.h>
#include "Arduino.h"
#define IO_USERNAME "Your Adafruit IO Username"
#define IO_KEY "Your Adafruit IO Key"
#define WIFI_SSID "your wifi ssid"
#define WIFI_PASS "your wifi password"
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET    -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define MENU D5
#define UP D6
#define DOWN D7
#define MEASURE D4
int menu = 0;
int celcius = 0;
int wifi = 1;
int body_temp = 1;
int patient_id = 1;
int display_on = 1;
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET); //Declaring the display name (display)
Adafruit_MLX90614 mlx = Adafruit_MLX90614();
AdafruitIO_WiFi io(IO_USERNAME, IO_KEY, WIFI_SSID, WIFI_PASS);
//AdafruitIO_Feed *temperature = io.feed("temperature");
void setup() {

pinMode(MENU, INPUT_PULLUP);
pinMode(UP, INPUT_PULLUP);
pinMode(DOWN, INPUT_PULLUP);
pinMode(MEASURE, INPUT_PULLUP);
/************************Read Configuration fromEEPROM***************************/
EEPROM.begin(512);  //Initialize EEPROM
celcius = EEPROM.read(0);
wifi = EEPROM.read(1);
body_temp = EEPROM.read(2);

mlx.begin();
display.begin(SSD1306_SWITCHCAPVCC, 0x3C); //Start the OLED display

home_page();

Serial.begin(9600);
delay(10000);
// connect to io.adafruit.com
if(wifi)connectAIO();
if(io.status() < AIO_CONNECTED){
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setFont();
display.setCursor(0,20);
display.println("No Internet Access!");
display.display();
delay(3000);
}

// we are connected
Serial.println();
Serial.println(io.statusText());

}
long time_count = millis();
void loop() {
if(!digitalRead(MENU)){
time_count = millis();
delay(200);
menu++;
if(menu>3) {
menu = 0;
EEPROM.write(0, celcius);
EEPROM.write(1, wifi);
EEPROM.write(2, body_temp);
EEPROM.commit();
}
}

if(!digitalRead(UP)){
time_count = millis();
delay(200);
if(menu==0) patient_id++;
if(menu==1) celcius = 1;
if(menu==2) wifi = 1;
if(menu==3) body_temp = 1;
}
if(!digitalRead(DOWN)){
time_count = millis();
delay(200);
if(menu==0) patient_id--;
if(menu==1) celcius = 0;
if(menu==2) wifi = 0;
if(menu==3) body_temp = 0;
}
if(wifi){
if(WiFi.status() != WL_CONNECTED){
WiFi.forceSleepWake();
delay(1);
WiFi.mode(WIFI_STA); //
WiFi.begin(WIFI_SSID, WIFI_PASS); //
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial1.print(".");
}
}
}
if(!wifi){
WiFi.disconnect(); //
WiFi.mode(WIFI_OFF);//
WiFi.forceSleepBegin();
delay(100);
}
if(menu == 0) home_page();
else if(menu == 1) scale_setup_page();
else if(menu == 2) wifi_setup_page();
else if(menu == 3) temp_setup_page();

if(!digitalRead(MEASURE)){
time_count = millis();
display.ssd1306_command(SSD1306_DISPLAYON);
display_on = 1;
Serial.println("Button Press");
delay(5000);
if(wifi){
if(io.status() >= AIO_CONNECTED){temp_write();
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setFont();
display.setCursor(0,20);
display.println("Data Sent!");
display.display();
delay(1500);
}
else{
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setFont();
display.setCursor(0,10);
display.println("No Internet access!");
display.display();
delay(1500);
}
}
//delay(3000);
}

if((millis()>= time_count + 50000) && display_on == 1){
display.ssd1306_command(SSD1306_DISPLAYOFF);
display_on = 0;
}
//display.ssd1306_command(SSD1306_DISPLAYON);
//io.run();
//temperature->save(tempF);
//delay(3000);

}
void home_page(){
float body_tempF = mlx.readObjectTempF()+ 4.5;
float ambient_tempF = mlx.readAmbientTempF();
float body_tempC = (body_tempF-32)/1.8;
float ambient_tempC = (ambient_tempF-32)/1.8;
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setFont();
display.setCursor(0,0);
if(body_temp)
display.println("Body Temperature");
else
display.println("Ambient Temp");
display.setFont(&FreeSerif12pt7b);
display.setCursor(20,40);
if(body_temp && celcius) display.println(body_tempC,2);
else if(body_temp && !celcius) display.println(body_tempF,2);
else if(!body_temp && !celcius) display.println(ambient_tempF,2);
else if(!body_temp && celcius) display.println(ambient_tempC,2);
//display.println(mlx.readObjectTempF()+4.5,2);
display.setCursor(80,40);
display.drawCircle(85, 28, 3, WHITE);
if(celcius) display.println("  C");
else display.println("  F");
display.setFont();
display.setCursor(0,55);
display.print("ID: P0");
display.println(String(patient_id));
display.setCursor(70,55);
if(WiFi.status() == WL_CONNECTED) display.println("WiFi: ON");
else display.println("WiFi: OFF");
display.display();
}

void scale_setup_page(){
display.clearDisplay();
display.setTextColor(WHITE);
display.setFont(&FreeSerif9pt7b);
display.setCursor(0,13);
display.println("Temp Scale");
display.setFont(&FreeSerif12pt7b);
display.drawCircle(65, 25, 3, WHITE);
display.drawRect(35, 25, 15, 15, WHITE);
display.setCursor(70,39);
display.println("C");
display.drawCircle(65, 45, 3, WHITE);
display.drawRect(35, 45, 15, 15, WHITE);
display.setCursor(70,60);
display.println("F");
if(celcius)
display.fillRect(37, 27, 11, 11, INVERSE);
else
display.fillRect(37, 47, 11, 11, INVERSE);
display.display();
}
void wifi_setup_page(){
display.clearDisplay();
display.setTextColor(WHITE);
display.setFont(&FreeSerif9pt7b);
display.setCursor(0,13);
display.println("WiFi Setup");
display.setFont(&FreeSerif12pt7b);
display.drawRect(10, 25, 15, 15, WHITE);
display.setCursor(40,39);
display.println("Enable");
display.drawRect(10, 45, 15, 15, WHITE);
display.setCursor(40,60);
display.println("Disable");
if(wifi)
display.fillRect(12, 27, 11, 11, INVERSE);
else
display.fillRect(12, 47, 11, 11, INVERSE);
display.display();
}
void temp_setup_page(){
display.clearDisplay();
display.setTextColor(WHITE);
display.setFont(&FreeSerif9pt7b);
display.setCursor(0,13);
display.println("Temperature");
display.setFont(&FreeSerif12pt7b);
display.drawRect(10, 25, 15, 15, WHITE);
display.setCursor(40,39);
display.println("Body");
display.drawRect(10, 45, 15, 15, WHITE);
display.setCursor(40,60);
display.println("Ambient");
if(body_temp)
display.fillRect(12, 47, 11, 11, INVERSE);
else
display.fillRect(12, 27, 11, 11, INVERSE);
display.display();
}
void power_saving_mode(){
display.ssd1306_command(SSD1306_DISPLAYOFF);
//wifi_station_disconnect();
wifi_set_opmode(NULL_MODE);
wifi_fpm_set_sleep_type(LIGHT_SLEEP_T);
wifi_fpm_open(); // Enables force sleep
//wifi_fpm_set_wakeup_cb(callback);
gpio_pin_wakeup_enable(GPIO_ID_PIN(MEASURE), GPIO_PIN_INTR_LOLEVEL); // GPIO_ID_PIN(2) corresponds to GPIO2 on ESP8266-01 , GPIO_PIN_INTR_LOLEVEL for a logic low, can also do other interrupts, see gpio.h above
wifi_fpm_do_sleep(0xFFFFFFF); // Sleep for longest possible time
}
void callback() {
display.ssd1306_command(SSD1306_DISPLAYON);
Serial1.println("Callback");
Serial.flush();
}
void temp_write(){
// set up `deepsleep` feed
String str = "P0";
str += patient_id;
int str_len = str.length() + 1;
char char_array[str_len];
str.toCharArray(char_array, str_len);
AdafruitIO_Feed *temperature = io.feed(char_array);
Serial.println("sending temperature to feed");
float body_tempF = mlx.readObjectTempF()+ 4.5;
float ambient_tempF = mlx.readAmbientTempF();
float body_tempC = (body_tempF-32)/1.8;
float ambient_tempC = (ambient_tempF-32)/1.8;
if(body_temp && celcius) temperature->save(body_tempC,2);
else if(body_temp && !celcius) temperature->save(body_tempF,2);
else if(!body_temp && !celcius) temperature->save(ambient_tempF,2);
else if(!body_temp && celcius) temperature->save(ambient_tempC,2);
// send data to deepsleep feed
//temperature->save(temp);
// write data to AIO
io.run();
}
void connectAIO() {
Serial.println("Connecting to Adafruit IO...");
io.connect();
long entering_time = millis();
// wait for a connection
while ((io.status() < AIO_CONNECTED) || (millis()> entering_time + 15000)) {
Serial.print(".");
delay(500);
}
// we are connected
Serial.println();
Serial.println(io.statusText());
}

Step 9: Assembling the Device

After uploading and testing the final work is to assemble the device. If after uploading the code everything goes well, place the battery to the battery holding unit. After placing the battery we need to connect the bottom part with the top part. Then we need to connect the sensor panel and the display panel with the body. Finally, we need to add the screw to tightly connect all the parts together. If you completed all the work then your device is ready to enjoy.