Measure Temperature and Humidity using M5Stack Core 2 with DHT11 and DHT22

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Project Details

Learn how to measure temperature and humidity with DHT11, DHT22, DHT21 sensor with M5Stack Core 2. First learn how to prepare Arduino IDE to work with M5Stack Core 2 ESCP3 device. Then wiring diagram for DHT11 DHT22 with PCB and bare module with resistor is shown. Actual wiring is shown next for all 3 modules. Then code is fully explained so you know how to customize it.
At the end measuring temperature and humidity is demonstrated using DHT11 and DHT22.

What values can this code show?

In the code where it says unsigned int unit=3; change the unit=0 to 5
0=C celsius
1=F fahrenheit
2=Humidity
3=C celsius and Humidity
4=F fahrenheit and Humidity
5=C celsius and F fahrenheit
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The link to use in the "preferences" of Arduino IDE
https://m5stack.oss-cn-shenzhen.aliyuncs.com/resource/arduino/package_m5stack_index.json Watch video for instructions.

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Project Code



 /*
 * file: M5Stack_DHT11_DHT22 
  Measure Temperature and Humidity using DHT11, DHT22, DHT21 Sensor and dispaly on M5Stack Core 2 ESP32 IoT board
 * Written by Ahmad Shamshiri on April 22, 2021 in Ontario, Canada
 * Watch video instruciton https://youtu.be/ZDZm_QOlCJo
 www.Robojax.com youTube http://youTube.com/robojaxTV
 
 * 
  * 
 * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.* 
 * This code has been download from Robojax.com
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see .

  
*/
#include 


const int refresh=3000;//read every 3 seconds

unsigned int unit=3;//
//              0=C celsius
//              1=F fahrenheit
//              2=Humidity
//              3=C and Humidity
//              4=F and Humidity
//              5=C and F

char *title[]={"Temperature","Temperature","Humidity"};
char *unitText[]={"C","F","%"};

//set more color. see https://docs.m5stack.com/#/en/api/lcd

unsigned int backgroundColor= YELLOW;
unsigned int temperatureTitleColor= BLACK;
unsigned int temperatureValueColor= RED;

unsigned int humidityTitleColor= BLACK;
unsigned int humidityValueColor= RED;

unsigned int background2Color= TFT_CYAN;

uint8_t titleV,unitV,degree;

uint8_t line1TitleY=3;
uint8_t line1ValueY=40;

uint8_t line2TitleY=110;
uint8_t line2ValueY=150;

#include "DHT.h"
#define DHTPIN 27 
//#define DHTTYPE DHT11   // DHT 11
#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
//#define DHTTYPE DHT21   // DHT 21 (AM2301)
DHT dht(DHTPIN, DHTTYPE);
float temperatureCValue,temperatureFValue, humidityValue,myValue1,myValue2;// 
// ****** DHT settings end (Robojax.com )

void readTemperature();
void displayTemperature(uint8_t line );
void setup() {

  M5.begin();
  M5.Lcd.setTextSize(4); 

  Serial.begin(9600);//default is 115200
  Serial.println("M5Stack DHT Test ");

 // Robojax.com code for ESP32 DHT11 DHT22
   dht.begin();  
delay(1000);
}

void loop() {
  readTemperature();//reads the temperature and humidity
  displayMyValue();//displays tempereture or humidity

  //printOnSerial();
   delay(refresh);
}


/*
 * www.robojax.com
 * see video https://youtu.be/ZDZm_QOlCJo 
 * for details
 */
void readTemperature()
{
  temperatureCValue = dht.readTemperature();// Read temperature as Celsius (the default)
  humidityValue = dht.readHumidity();// Reading humidity 
  temperatureFValue = dht.readTemperature(true);// Read temperature as Fahrenheit (isFahrenheit = true)

}//readTemperature() end

void displayMyValue()
{
  
  switch (unit) {
    case 1:
      titleV = 1;
      unitV =1; 
      myValue1= temperatureFValue;    
      displayTemperature( 1 , true);    
    break;

    case 2:
      titleV = 2;
      unitV =2;   
      myValue1= humidityValue;  
     displayTemperature( 1, false );    
    break;

    case 3:
      titleV = 0;
      unitV =0;     
      myValue1= temperatureCValue;      
      displayTemperature( 1 , true);
 
      titleV = 2;
      unitV =2;  
      myValue2= humidityValue; 
      displayTemperature( 2, false );               
    break;

    case 4:
      titleV = 1;
      unitV =1;     
      myValue1= temperatureFValue;      
      displayTemperature( 1 , true);
 
      titleV = 2;
      unitV =2;  
      myValue2= humidityValue; 
      displayTemperature( 2 , false);      
    break;

    case 5:
      titleV = 0;
      unitV =0;     
      myValue1= temperatureCValue;      
      displayTemperature( 1, true);
 
      titleV = 1;
      unitV =1;  
      myValue2= temperatureFValue; 
      displayTemperature( 2 , true);         
    break;

    default:
      titleV = 0;
      unitV =0;    
      myValue1= temperatureCValue;
      displayTemperature(1, true);    
    break;
    
  }

 
}//displayMyValue() end

/*
 * isplayTemperature(uint8_t line, bool degree)
 * Displays temperature on Core2 screen
 * See video for details
 * https://youtu.be/ZDZm_QOlCJo
 */
void displayTemperature(uint8_t line, bool degree)
{
  uint8_t Y_lineTitle,Y_lineValue;
  float valueToDisplay;
  //M5.Lcd.fillScreen(backgroundColor);
  M5.Lcd.setTextColor(temperatureTitleColor);  
 
  M5.Lcd.setTextSize(4);
  if(line ==1){
    Y_lineTitle =line1TitleY;
    Y_lineValue =line1ValueY;
    valueToDisplay=myValue1;
    //M5.Lcd.fillRect(0, 0, 340, line2TitleY, backgroundColor);            
   M5.Lcd.fillScreen(backgroundColor);     
  }else{
    //M5.Lcd.drawRect(0, line2TitleY, 340, 240-line2TitleY, background2Color);
    M5.Lcd.fillRect(0, line2TitleY, 340, 240-line2TitleY, background2Color);      
    Y_lineTitle =line2TitleY;
    Y_lineValue =line2ValueY; 
    valueToDisplay=myValue2;
  }

  M5.Lcd.setCursor(3,Y_lineTitle); 
 
  M5.Lcd.print(title[titleV]);
  M5.Lcd.setTextColor(temperatureValueColor);    
  M5.Lcd.setTextSize(7);  
  M5.Lcd.setCursor(3,Y_lineValue);  
  M5.Lcd.printf("%.1f", valueToDisplay);  
  if(degree){
   printDegree();//print degree symbol if needed
  }
  M5.Lcd.print(unitText[unitV]);    
}
/*
 * displayHumidity()
 * displays humidity from DHT11 or DHT22 on Core 2
 * written by Ahmad Shamshiri
 * on April 21, 2021 in Ajax, Ontario, Canada
 * www.Robjax.com
 */
void displayHumidity()
{

  M5.Lcd.setTextColor(humidityTitleColor);      
  M5.Lcd.setTextSize(4);    
  M5.Lcd.setCursor(3,110); 
  M5.Lcd.print(title[2]); //humidity title   
  M5.Lcd.setTextColor(humidityValueColor);    
  M5.Lcd.setTextSize(7);  
  M5.Lcd.setCursor(3,150);   
  M5.Lcd.printf("%.1f", humidityValue);       
  M5.Lcd.print(unitText[2]);    

}//displayHumidity() end


/*
 * printDegree()
 * prints degree symbol
 * Written by Ahmad Shamshiri 
 * on April 2, 2021 at 23:53
 * www.robojax.com
 */
void printDegree()
{

  M5.Lcd.setTextSize(3);  
  
  M5.Lcd.print("o");  
  M5.Lcd.setTextSize(7);    
  M5.Lcd.setCursor(M5.Lcd.getCursorX()+15,M5.Lcd.getCursorY());   
}//printDegree() end

/*
written by Ahmad Shamshiri for Robojax, Robojax.com
on April 21, 2021 in Ajax, Ontario, Canada
*/
void printOnSerial()
{
      Serial.print(title[unit]); 
      Serial.print(" "); 
      Serial.print(myValue1);  
             
      Serial.print(unitText[unit]);      
      Serial.println();  
}//printOnSerial() end
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