DHT22 temperature and humidity sensor: specs and pinout
Digital temperature and humidity sensor with a single-wire output, rated for 0 to 100 %RH and -40 to 80 °C.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage | 3.3 V to 6 V DC | source Specification table; power supply section |
| Humidity range | 0 to 100 %RH | source Specification table (range) |
| Temperature range | -40 to 80 °C | source Specification table (range) |
| Humidity accuracy | ±2 %RH typical; ±5 %RH maximum | source Specification table (accuracy) |
| Temperature accuracy | ±0.5 °C | source Specification table (accuracy) |
| Collecting period | More than 2 seconds between readings | source Communication section (collecting period) |
Power
| Value | Source | |
|---|---|---|
| Supply | 3.3 V to 6 V DC | source Specification table; power supply section |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently. Module header labels (VCC, GND, SDA, SCL…) come from the Compoden listing, not an official module schematic.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| VDD (pin 1) | Power supply | 3.3 V to 6 V DC | A 100 nF capacitor between VDD and GND is suggested | source Pin Function / Power and Pins |
| DATA (pin 2) | Signal (single bus) | Data-line voltage limits are not stated in the datasheet | source Pin Function / Power and Pins | |
| NC (pin 3) | Not connected ("NULL" in the datasheet) | source Pin Function / Power and Pins | ||
| GND (pin 4) | Ground | source Pin Function / Power and Pins |
Common mistakes
- Sending commands while the sensor is powering up: the datasheet says not to send any instruction when power is applied (source)
- Reading more often than every 2 seconds: the collecting period should be more than 2 seconds (source)
- Requesting humidity outside 0 to 100 %RH: the datasheet does not recommend operating beyond the stated RH range (source)
What we could not confirm
- Resolution row is blank in the datasheet copy. Not stated.
- Current consumption is not given in the datasheet copy. Not stated.
- The specification table in the datasheet copy is unclear. Values are taken from the adjacent lines. Confirm on the PDF.
- Pin rows are the 4-pin DHT22 / AM2302 sensor body (Aosong datasheet, a hosted copy). The listing's module header has 3 pins (VCC, GND, DATA) and omits NC; module pull-up is not from an official source.
Sources
- Aosong DHT22 / AM2302 datasheet (copy hosted by a hosted copy: link).
- Copy of the Aosong DHT22 datasheet hosted by a hosted copy (sparkfun.com/datasheets/Sensors/Temperature/DHT22.pdf).
Building with the DHT22 temperature and humidity sensor? Describe your project on Soldr: it assigns pins from the board's published pinout, checks power and logic levels, and shows how to wire every part.