NodeMCU and TEMPERATURE AND HUMIDITY SENSOR with Oled display ( ESP8266 or ESP32 )

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
int DHpin = D3; // input/output pin
byte dat[5];   
byte read_data()
{
  byte i = 0;
  byte result = 0;
  for (i = 0; i < 8; i++) {
      while (digitalRead(DHpin) == LOW); // wait 50us
      delayMicroseconds(30); //The duration of the high level is judged to determine whether the data is '0' or '1'
      if (digitalRead(DHpin) == HIGH)
        result |= (1 << (8 - i)); //High in the former, low in the post
    while (digitalRead(DHpin) == HIGH); //Data '1', waiting for the next bit of reception
    }
  return result;
}
void start_test()
{
  digitalWrite(DHpin, LOW); //Pull down the bus to send the start signal
  delay(30); //The delay is greater than 18 ms so that DHT 11 can detect the start signal
  digitalWrite(DHpin, HIGH);
  delayMicroseconds(40); //Wait for DHT11 to respond
  pinMode(DHpin, INPUT);
  while(digitalRead(DHpin) == HIGH);
  delayMicroseconds(80); //The DHT11 responds by pulling the bus low for 80us;
  
  if(digitalRead(DHpin) == LOW)
    delayMicroseconds(80); //DHT11 pulled up after the bus 80us to start sending data;
  for(int i = 0; i < 5; i++) //Receiving temperature and humidity data, check bits are not considered;
    dat[i] = read_data();
  pinMode(DHpin, OUTPUT);
  digitalWrite(DHpin, HIGH); //After the completion of a release of data bus, waiting for the host to start the next signal
}
void setup()
{   display.begin(SSD1306_SWITCHCAPVCC, 0x3C);  
    display.clearDisplay();
// Display Text
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(5,0);
  display.println(" TEMPERATURE ");
  display.display();
   display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(5,28);
  display.println(" & HUMIDITY ");
  display.display();
  delay(2000);
Serial.begin(9600);
  pinMode(DHpin, OUTPUT);
}
void loop()
{
 start_test();
  Serial.print("Humdity = ");
  Serial.print(dat[0], DEC); //Displays the integer bits of humidity;
  Serial.print('.');
  Serial.print(dat[1], DEC); //Displays the decimal places of the humidity;
  Serial.println('%');
  Serial.print("Temperature = ");
  Serial.print(dat[2], DEC); //Displays the integer bits of temperature;
  Serial.print('.');
  Serial.print(dat[3], DEC); //Displays the decimal places of the temperature;
  Serial.println('C');
  byte checksum = dat[0] + dat[1] + dat[2] + dat[3];
  if (dat[4] != checksum) 
    Serial.println("-- Checksum Error!");
  else
    Serial.println("-- OK");
 
  delay(1000);
// Clear the buffer.
  display.clearDisplay(); // Display Text
  display.setTextSize(1.5);
  display.setTextColor(WHITE);
  display.setCursor(10,3);
 display.println( "Humdity = "+ String(dat[0], DEC) +"."+ String(dat[1], DEC) +"%"); display.display();
   display.setTextSize(1.9);
  display.setTextColor(WHITE);
  display.setCursor(10,28); display.println( "Temp. = "+ String(dat[2], DEC) +"."+ String(dat[3], DEC) +"C");
  display.display();
  delay(2000);
}