DHT11 Relative Humidity- Temperature - Sensor Module For Arduino
Can detect surrounding environment of the humidity and temperature
Humidity measurement range: 20% ~ 95%
Humidity measurement error: +/- 5%
Temperature measurement range: 0°C ~ 50°C
Temperature measurement error: +/- 2°C
Working voltage 3.3V ~ 5V
Output 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)
mode: DIGITAL OUTPUT
PCB size: 3.1 x 1.4cm
Pin connections of DHT11 Sensor : PIN1- Vcc PIN2-DATA- Signal output PIN3-Not connected PIN4-GND
Simply ignore pin 3, its not used. Place a 10K resistor between VCC and the data pin, to act as a medium-strength pull up on the data line.
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 gives out a digital signal with the temperature and humidity. The digital signal is fairly easy to read using any microcontroller.