DHT22/AM230x/RHT0x Temperature and RH Sensor
This module interfaces with the DHT22 (also DHT21, DHT22, DHT33, DHT44, RHT01, RHT02, RHT03, RHT04, RHT05, AM2301, AM2302, AM2303 and HM2301), an inexpensive temperature and relative humidity sensor similar to the DHT11, but with higher accuracy and wider range.
|Temperature Range||-40~80 C|
|Temp. Accuracy||+/- 0.5C|
|Humidity Range||0 ~ 100%|
|Humidity Accuracy||+/- 2%|
The module will retry if it doesn’t get any response, or if other sanity checks fail. If it fails 10 times in a row, the callback will be called with an error (see below), indicating a likely problem with the sensor or wiring. The DHT22 is much more reliable than the DHT11, and it rarely fails to provide data, however, it is still important to perform your own sanity checks on the data returned.
The DHT22 is a basic, low-cost digital temperature and humidity sensor. 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). It’s fairly simple to use, but requires careful timing to grab data. The only real downside of this sensor is you can only get new data from it once every 2 seconds, so when using our library, sensor readings can be up to 2 seconds old.
- Power supply: 3- 5V.
- Current: 2.5mA max use of current during conversion (while requesting data).
- Humidity: 0 – 100%, ± 2%.
- Temperature: -40°C + 125°C, ± 0.5%.
- The sampling rate no more than 0.5 Hz (once every 2 seconds).