DHT 21 temperature and humidity is a sensor unit that is able to generate calibrated digital output signals. It is very reliable and stabile for long periods of operation. It contains a 8 - bit microcontroller internally and responses clear and fast.

It is able to measure temperature between -40 and 80 degrees with -/+ 1 degrees of error margin, likewise, it is able to measure humidity between 0% RH to 100% RH with +/- 5% RH of error margin. It is possible to collect data from this breakout once in 2 seconds. DHT22 is a bit larger than the other models of DHT sensors.

Features:

• One of the highes performance products of DHT series
• Generates digital signals as output
• Operating voltage: 3.3 V to 5 V DC
• Measuring range:
       -Humidity: 0-100%RH
       -Temperature: -40 - 80 °C
• Precision:
       -Humidity: +/- %3 (Max %5) RH
       -Temperature: < +/- 1 °C

• Measuring Periaod: 2 s
• Sizes of product: 27 mm x 59 mm x 13.5 mm

Note: It is needed to wire a pull-up resistor between the Vcc and the output pins. By this reason, You will need to use is with a resistor between 4.7 k and 10 k. As the DHT11 is a similar version of this product, all the projects done with this sensor will work on the other model too.

Documents:

• Click here to see the datasheet of this product.
• Click here to see the DHT sensor page on Arduino web site.
• Click here to see the example application on Raspberry Pi.