Published November 21, 2022

Wearable Human Temperature&Humidity Monitor

Through temperature and humidity Sensor and air pressure, OLED, LEDs and buzzers indicate possible acute diseases that threaten human healt

BeginnerFull instructions provided5 hours194

Wearable Human Temperature&Humidity Monitor

Things used in this project

Hardware components

Seeed Studio Seeeduino Lotus V1.1 - ATMega328 Board with Grove Interface

Seeed Studio Grove - Piezo Buzzer

Seeed Studio Grove - RED LED

Seeed Studio Grove - Temperature & Humidity Sensor (DHT11)

Seeed Studio grove Air Pressure Sensor

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Laser cutter (generic)

Story

Introduction

Temperature is a key data that affects human survival. People live in nature, and the temperature affects people's life, work and all activities every moment. So, what are the effects of temperature on human health?

In a high temperature environment, the human body loses heat through evaporation to maintain the balance of body temperature. In the process of sweating, salt in the body will be lost with sweat, blood concentration, hemoglobin, etc. will increase, blood viscosity will increase, and the burden of heart blood vessels will increase, which will cause blood pressure to drop. In order to maintain normal blood pressure, the burden of the heart will be heavier. The skin of the human body perspires a lot, reducing the water excreted by the kidney, which also affects the renal function. High temperature also affects human nervous activity and motor coordination, and even threatens life in serious cases. For example: heatstroke.

When the body cannot adapt to and tolerate high ambient temperature (>32 ℃), high humidity (>60%) and no wind, the body generates more heat than it emits, which leads to heat accumulation, temperature rise, and heatstroke.

From summer to winter, the temperature drops significantly. In a low temperature environment, the human body strengthens tissue metabolism to maintain the heat balance of the body, and the oxygen demand increases. If the above conditions cannot be met, the human body will consume the reserves of cells in the body, thus creating an irreversible environment for human tissues. In addition, because the outdoor temperature is very low in winter, the blood vessels of the human body tend to become hard and brittle, especially the middle-aged and elderly people should pay special attention to clothing and keep warm. When the temperature is lowest in the morning, the time of outdoor morning exercise should be postponed to avoid life danger caused by blood vessel rupture due to low temperature. Another threat factor is temperature loss. The famous historical event "Titanic", from hitting an iceberg to completely sinking for more than 2 hours, only 710 people managed to escape and 1514 people died. The vast majority of the 1514 victims were not directly drowned by sea water, but froze to death in - 2 ℃ sea water for a long time.

Loss of temperature, also known as hypothermia, does not mean that it can only occur in cold weather. In fact, when the temperature is below 20 ℃, the loss of temperature begins to threaten hikers. According to the accident report in North America, 0-10 ° C is the high incidence range of hypothermia. Loss of temperature means that the loss of heat in the human body is greater than the heat supply, resulting in a decrease in the temperature of the core area of the human body, and a series of symptoms such as chills, confusion, cardiopulmonary failure, and even death. Here, the so-called core area of the human body mainly refers to the heart, lungs and other vital organs in the brain and trunk. This concept is relative to the human limbs and surface skin.

How does loss of temperature cause death

When the ambient temperature is lower than the body temperature, the symptoms of temperature loss will occur, especially when the temperature is about 10 ℃. During outdoor sports, we are easily paralyzed by the ambient temperature. When we sweat heavily, wet clothes will increase the heat conduction speed of the body, which is five times that of dry clothes. The speed of body temperature reduction is greater than the speed of body heat production, and temperature loss occurs. At this time, if there is no timely treatment, the temperature loss will become more and more serious, and eventually lead to death.

Therefore, I have made a portable temperature and humidity monitoring instrument to monitor the change of human body temperature, so as to give early warning in time.

Components Required

Seeeduino Lotus V1.1 is a small update of the V1.0 version, we only changed the USB bus converter chip CH340 to CP2102N in order to make this board more compatible with Mac OS. Despite this change, the board is still based on ATMEGA328P-MU, a high performance, low power 8-Bit AVR Microcontroller. It is still Arduino compatible and has rich peripherals including digital interface, analog interface, I2C, SPI, UART.
Grove - DHT11 Temperature & Humidity Sensor is a high quality, low-cost digital temperature, and humidity sensor based on the DHT11 module.
Grove - Red LED is similar to the Grove - LED module which houses an LED light source. In addition, it also has a potentiometer on board to manage the power requirements of the LED. The PCB of this module has mounting holes which can be mounted on the required surface of your prototype. For example, it can be used as a pilot lamp for indicating power or signal presence.
Grove - Buzzer is a simple yet enjoyable twig to use. It can output noise at a volume over 85 dB and is integrated with the Grove interface, which makes it easy to connect and experiment by just plug & play. It is a perfect add-on for all kinds of Arduino projects and human-machine interfaces

Steps Required

Connect the multi-channel sensor to the Wio terminal and read

Assembling and connecting the sensor
Find a suitable box to pack

Cutting sensor interface with laser cutter

1 / 4

Done!

This project is not very complete and suitable for wearing, but as a demo, it can already realize relevant functions. There may be upgrading iterations later, such as replacing the air pressure module with VOC gas monitoring, pm2.5 sensor, etc.

Hope you guys like it.

Wearable human temperature and humidity monitor

//----- [oled] - (A) -------v
#include <U8x8lib.h>
U8X8_SSD1306_128X64_ALT0_HW_I2C
oled(/* reset=*/U8X8_PIN_NONE);
//-------------------------------------^
//----- [] - (A) -------v
#include "DHT.h"
#define DHTPIN 3  // D3
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);
float temperature;
float humidity;
//----------------------------------------------^
//---------- [] - (A) --------v
#include "Seeed_BMP280.h"
#include <Wire.h>
BMP280 bmp280;
float pressure;
float altitude;
//--------------------------------------------^
#define BUZZ_PIN 5
#define MY_LED 4


void setup() {

  // put your setup code here, to run once:
  Serial.begin(9600);
  //--------[oled] - (B) --------v
  oled.begin();
  oled.setFlipMode(1);  //01
  oled.setFont(u8x8_font_chroma48medium8_r);
  //------------------------------------------^
  //--------[] - (B) --------v
  dht.begin();
  temperature = 0;
  humidity = 0;
  //----------------------------------------------^
  //-------- [] - (B) ---------v
  if (!bmp280.init()) {
    Serial.println("Device not connected or broken!");
  }
  pressure = 0;
  //----------------------------------------^
  pinMode(MY_LED, OUTPUT);
}

void loop() 
{
  // put your main code here, to run repeatedly:

  //--------[oled] - (C) --------v
  oledPrint(0, "     WARNING" );
  oledPrint(1, "TEMP   " + String(temperature));  //
  oledPrint(2, "HUM    " + String(humidity));
  oledPrint(3, "ATM    " + String(pressure));  //
  //------------------------------------------^
  //--------[] - (C) ---------v
  //
  temperature = getTemperature();
  //
  humidity = getHumidity();
  //------------------------------------------^
  //-----------[] - (C) -----------v
  pressure = getPressure();
  altitude = getAltitude();
  //-------------------------------------------^
  

    if (temperature > 30) {
      analogWrite(BUZZ_PIN, 2000);
      delay(100);
      analogWrite(BUZZ_PIN, LOW);
      delay(100);
      digitalWrite(MY_LED, HIGH);
      delay(100);
      digitalWrite(MY_LED, LOW);
      delay(100);
      analogWrite(BUZZ_PIN, 2000);
      delay(100);
      analogWrite(BUZZ_PIN, 0);
      delay(100);
      digitalWrite(MY_LED, HIGH);
      delay(100);
      digitalWrite(MY_LED, LOW);
      delay(100);
      analogWrite(BUZZ_PIN, 2000);
      delay(100);
      analogWrite(BUZZ_PIN, 0);
      delay(100);
      digitalWrite(MY_LED, HIGH);
      delay(100);
      digitalWrite(MY_LED, LOW);
      delay(100);
      analogWrite(BUZZ_PIN, 2000);
      delay(100);
      analogWrite(BUZZ_PIN, 0);
      delay(100);
      digitalWrite(MY_LED, HIGH);
      delay(100);
      digitalWrite(MY_LED, LOW);
      delay(100);
    } 
    else if (temperature > 27) {
    analogWrite(BUZZ_PIN, 2000);
    delay(200);
    analogWrite(BUZZ_PIN, 0);
    delay(200);
    digitalWrite(MY_LED, HIGH);
    delay(200);
    digitalWrite(MY_LED, LOW);
    delay(200);
    analogWrite(BUZZ_PIN, 2000);
    delay(200);
    analogWrite(BUZZ_PIN, 0);
    delay(200);
    digitalWrite(MY_LED, HIGH);
    delay(200);
    digitalWrite(MY_LED, LOW);
    delay(200);
   }
    else {
      analogWrite(BUZZ_PIN, 0);

      digitalWrite(MY_LED, LOW);
    }
  }

  //--------[oled] - (D) --------v
  /**
 * oledPrint
 * oled_line4
 * oled_str,16
 */
  void oledPrint(int oled_line, String oled_str) {
    oled.clearLine(oled_line);  //oled_line
    oled.setCursor(0, oled_line);
    oled.print(oled_str);
  }
  //-------------------------------------^
  //--------[] - (D) ---------v
  // 250
  // 
  float getHumidity() {
    return dht.readHumidity();
  }

  float getTemperature() {
    //true == ; false == 
    return dht.readTemperature(false);
  }
  //----------------------------------------------^
  //-------------[] - (D) -----------v
  float getPressure() {
    return bmp280.getPressure();
  }

  float getAltitude() {
    return bmp280.calcAltitude(bmp280.getPressure());
  }
  //---------------------------------------------^