5. DHT22 - Digital Temperature and Humidity Sensor

5.1. Description

The DHT22 is a low-cost digital temperature and humidity sensor with a single wire digital interface. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air and spits out a digital signal on the data pin (no analog input pins needed).

The sensor is calibrated and doesn’t require extra components so you can get the right to measuring relative humidity and temperature.

It is quite simple to use but requires careful timing to grab data. You can only get new data from it once every 2 seconds.


DHT22 - AM2302

5.2. How it works?

Connect the first pin on the left to 3-5V power, the second pin to your data input pin and the right most pin to ground.



Although it uses a single-wire to send data it is not Dallas One Wire compatible! If you want multiple sensors, each one must have its own data pin!

5.3. Technical details

Power supply3.3-6V DC
Output signalDigital signal via 1-wire bus
Sensing elementPolymer capacitor
Operating rangeHumidity 0-100%RH;
Temperature -40~80Celsius
AccuracyHumidity +-2%RH(Max +-5%RH);
Temperature <+-0.5Celsius
Resolution or sensitivityHumidity 0.1%RH;
Temperature 0.1Celsius
RepeatabilityHumidity +-1%RH;
Temperature +-0.2Celsius
Humidity hysteresis+-0.3%RH
Long-term stability+-0.5%RH/year
Sensing periodAverage: 2s
InterchangeabilityFully interchangeable
DimensionsSmall size 14185.5mm;
Big size 22285mm

5.4. Data sheet

4.5. Where to buy?