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.
Note
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
| Model | DHT22/AM2302 |
| Power supply | 3.3-6V DC |
| Output signal | Digital signal via 1-wire bus |
| Sensing element | Polymer capacitor |
| Operating range | Humidity 0-100%RH; Temperature -40~80Celsius |
| Accuracy | Humidity +-2%RH(Max +-5%RH); Temperature <+-0.5Celsius |
| Resolution or sensitivity | Humidity 0.1%RH; Temperature 0.1Celsius |
| Repeatability | Humidity +-1%RH; Temperature +-0.2Celsius |
| Humidity hysteresis | +-0.3%RH |
| Long-term stability | +-0.5%RH/year |
| Sensing period | Average: 2s |
| Interchangeability | Fully interchangeable |
| Dimensions | Small size 14185.5mm; Big size 22285mm |
5.4. Data sheet
4.5. Where to buy?
Updated almost 5 years ago