Interface DHT-11 with NodeMCU

In this tutorial, we will interface DHT-11 with NodeMCU. To setup NodeMCU board in Arduino software visit this post.

CONNECTIONS :

                NodeMCU              DHT11
                5v          -        5v
                Gnd         -        Gnd
                D4          -        Data pin

PROCEDURE:

Download the Dht library from https://github.com/adafruit/DHT-sensor-library
While compiling if it shows Adafruit_Sensor.h missing download it from https://github.com/adafruit/Adafruit_Sensor
Extract the libraries and paste it into the library folder of Arduino(It will be in C:/Program Files (x86)/Arduino/libraries)
You can open the example program from File–>Examples–>DHT Sensor Library–>DHTtester

PROGRAM:

 
#include "DHT.h"
#define DHTPIN D4     
#define DHTTYPE DHT11   // DHT 11
 
DHT dht(DHTPIN, DHTTYPE);
 
void setup() {
  Serial.begin(9600);
  Serial.println("DHTxx test!");
 
  dht.begin();
}
 
void loop() {
  // Wait a few seconds between measurements.
  delay(2000);
 
  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);
 
  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
 
  // Compute heat index in Fahrenheit (the default)
  float hif = dht.computeHeatIndex(f, h);
  // Compute heat index in Celsius (isFahreheit = false)
  float hic = dht.computeHeatIndex(t, h, false);
 
  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print(" %\t");
  Serial.print("Temperature: ");
  Serial.print(t);
  Serial.print(" *C ");
  Serial.print(f);
  Serial.print(" *F\t");
  Serial.print("Heat index: ");
  Serial.print(hic);
  Serial.print(" *C ");
  Serial.print(hif);
  Serial.println(" *F");
}