A simple Arduino sketch to read temperature and humidity data from a DHT11 sensor

Here is a simple Arduino sketch to read temperature and humidity data from a DHT11 sensor and display it on the Serial Monitor:

DHT11 Arduino Sketch (Using DHT Library)
Hardware Required

• Arduino board (e.g., Uno, Nano)
• DHT11 sensor
• 10kΩ resistor (optional, for pull-up on data pin)
• Jumper wires

Wiring (DHT11 with 3 pins or module)

Step 1: Install Library
In Arduino IDE:
Sketch → Include Library → Manage Libraries → Search "DHT sensor library" by Adafruit → Install

Also install:
"Adafruit Unified Sensor" library

Step 2: Arduino Code

cpp

#include <DHT.h>

// Define the pin where the DHT11 is connected
#define DHTPIN 2       
#define DHTTYPE DHT11   // DHT11 or DHT22

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  dht.begin();
  Serial.println("DHT11 Sensor Reading Started...");
}

void loop() {
  delay(2000);  // DHT11 needs 1-2 seconds delay between readings

  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature(); // Celsius

  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("Failed to read from DHT11 sensor!");
    return;
  }

  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.print("°C  |  Humidity: ");
  Serial.print(humidity);
  Serial.println("%");
}

Example Output in Serial Monitor

yaml

DHT11 Sensor Reading Started...
Temperature: 25.00°C  |  Humidity: 58.00%
Temperature: 25.10°C  |  Humidity: 59.00%