Aosong ASAIR AHT1x/AHT2x
This is an Arduino library for Aosong ASAIR AHT10/AHT15/AHT20/AHT21/AHT25/AM2301B/AM2311B Digital Humidity & Temperature Sensor
- AHT1x +1.8v..+3.6v, AHT2x +2.2v..+5.5v
- AHT1x 0.25uA..320uA, AHT2x 0.25uA..980uA
- temperature range -40C..+85C
- humidity range 0%..100%
- typical accuracy T +-0.3C, RH +-2% (1)
- typical resolution T 0.01C, RH 0.024%
- normal operating range T -20C..+60C, RH 10%..80%
- maximum operating rage T -40C..+80C, RH 0%..100%
- I2C bus speed 100KHz..400KHz, 10KHz recommended minimum
- recommended measurement frequency 8sec..30sec (2)
- recommended to route VDD or GND between I2C lines to reduce crosstalk between SCL & SDA
- power supply pins must be decoupled with 100nF capacitor
Supports all sensors features:
- read humidity (3)
- read temperature (3)
- soft reset with sensor initialization
- CRC calculation for AHT2x (3)
Tested on:
- Arduino AVR
- Arduino ESP8266
- Arduino ESP32
- Arduino STM32
(1) Prolonged exposure for 60 hours at humidity > 80% can lead to a temporary drift of the signal +3%. Sensor slowly returns to the calibrated state at normal operating conditions.
(2) Measurement with high frequency leads to heating of the sensor, must be > 2 seconds apart to keep self-heating below 0.10C.
(3) Library returns 255 if a communication error occurs, calibration coefficient is off or CRC doesn't match (for AHT2x only).