Can detect surrounding environment of the humidity and temperature

Humidity measurement range: 20 Percent Minus 95 Percent, humidity measurement error: Plus Minus 5 Percent
Temperature measurement range: 0 to 50 ;measurement error: Plus Minus 2 degrees
Working voltage 3.3 ~ 5V
Output form: digital output
Has fixed bolt hole and easy installation

DHT11 Temperature and Humidity Sensor features a temperature and humidity sensor complex with a calibrated digital signal output. By using the exclusive digital signal acquisition technique and temperature and humidity sensing technology, it ensures high reliability and excellent long term stability. This sensor includes a resistive type humidity measurement component and an NTC temperature measurement component, and connects to a high-performance 8bit microcontroller, offering excellent quality, fast response, anti interference ability 

This tutorial will help you use DHT11 Temperature and Humidity Sensor Module for Arduino:

#include "dht.h"
#define dht_apin A0 // Analog Pin sensor is connected to
 
dht DHT;
 
void setup(){
 
  Serial.begin(9600);
  delay(500);//Delay to let system boot
  Serial.println("DHT11 Humidity & temperature Sensor\n\n");
  delay(1000);//Wait before accessing Sensor
 
}//end "setup()"
 
void loop(){
  //Start of Program 
 
    DHT.read11(dht_apin);
    
    Serial.print("Current humidity = ");
    Serial.print(DHT.humidity);
    Serial.print("%  ");
    Serial.print("temperature = ");
    Serial.print(DHT.temperature); 
    Serial.println("C  ");
    
    delay(5000);//Wait 5 seconds before accessing sensor again.
 
  //Fastest should be once every two seconds.
 
}// end loop()