DHT11 is a Humidity and Temperature Sensor, which generates calibrated digital output. DHT11 can be interface with any microcontroller like Arduino, Raspberry Pi, etc. and get instantaneous results. 
 
It uses a capacitive humidity sensor and a thermistor to measure the surrounding air, and outputs a digital signal on the data pin (no analog input pins needed). Its very simple to use, and libraries and sample codes are available for Arduino and Raspberry Pi. 
 
This module makes is easy to connect the DHT11 sensor to an Arduino or microcontroller as includes the pull up resistor required to use the sensor. Only three connections are required to be made to use the sensor - Vcc, Gnd and Output. 
 
It has high reliability and excellent long-term stability, thanks to the exclusive digital signal acquisition technique and temperature & humidity sensing technology. But despite its disadvantages over DHT22, it is a smaller and less expensive sensor for temperature and humidity measurement.
 
Features :
Low power consumption.
DHT11 sensor adopts
The module can detect the surrounding environment of the humidity and temperature
High reliability and excellent long-term stability
The output from the digital output
Has fixed bolt hole and easy installation
Specifications:
Humidity Measuring Range(%)
20 to 90
Temperature Measuring Range(°C)
0 to +50
Humidity Measurement Accuracy(%)
±5.0
Temperature Measurement Accuracy(°C)
±2.0
Response Time(s)
<5
Supply Voltage (V)
5v DC