DHT11 sensor with ESP8266/NodeMCU using Arduino IDE

6th March 2019| 19th February 2020 20 Comments 3 min read

In this tutorial i a telling to you How to use DHT11 sensor with ESP8266/NodeMCU using Arduino IDE. First i am telling to you about DHT11 and DHT22 temperature and humidity sensor and Difference between DHT11 and DHT22.

What is DHT11 and DHT22?

The DHT11 and DH22 are both temperature and humidity sensors, but what’s the difference between the two? Let’s go through the important differences, and how they may affect which one you choose for your next project. These sensors are very basic and slow, but are great for hobbyists who want to do some basic data logging. The DHT sensors are made of two parts, a capacitive humidity sensor and a thermistor. There is also a very basic chip inside that does some analog to digital conversion and spits out a digital signal with the temperature and humidity. The digital signal is fairly easy to read using any microcontroller.

DHT11 vs DHT22

We have two versions of the DHT sensor, they look a bit similar and have the same pinout, but have different characteristics. Here are the specs:

DHT11

Ultra low cost
3 to 5V power and I/O
2.5mA max current use during conversion (while requesting data)
Good for 20-80% humidity readings with 5% accuracy
Good for 0-50°C temperature readings ±2°C accuracy
No more than 1 Hz sampling rate (once every second)
Body size 15.5mm x 12mm x 5.5mm
4 pins with 0.1″ spacing

DHT22

Low cost
3 to 5V power and I/O
2.5mA max current use during conversion (while requesting data)
Good for 0-100% humidity readings with 2-5% accuracy
Good for -40 to 80°C temperature readings ±0.5°C accuracy
No more than 0.5 Hz sampling rate (once every 2 seconds)
Body size 15.1mm x 25mm x 7.7mm
4 pins with 0.1″ spacing

As you can see, the DHT22 is a little more accurate and good over a slightly larger range. Both use a single digital pin and are ‘sluggish’ in that you can’t query them more than once every second or two.

DHT11 sensor with ESP8266/NodeMCU using Arduino IDE

Make the following connections –

Now You need to two libraries, Download these libraries.

https://drive.google.com/drive/folders/1SYM_B1k3SE0Qkxa3NFsw7W2IyVzNVJhq?usp=sharing

Arduino .ino Code


#include "DHT.h"        // including the library of DHT11 temperature and humidity sensor
#define DHTTYPE DHT11   // DHT 11

#define dht_dpin 0
DHT dht(dht_dpin, DHTTYPE); 
void setup(void)
{ 
  dht.begin();
  Serial.begin(9600);
  Serial.println("Humidity and temperature\n\n");
  delay(700);

}
void loop() {
    float h = dht.readHumidity();
    float t = dht.readTemperature();         
    Serial.print("Current humidity = ");
    Serial.print(h);
    Serial.print("%  ");
    Serial.print("temperature = ");
    Serial.print(t); 
    Serial.println("C  ");
  delay(800);
}

Output

Upload the above code to the NodeMCU and open serial monitor. Following output should be shown on the serial monitor