This dual-purpose sensor is used to measure temperature and humidity. It operates as an I2C slave device.

WARNING: The AHT10 has a hardware bug which means it cannot share the bus with any other device.

Refer to data-sheet figure 11 comment 3: Only a single AHT10 can be connected to the I2C bus and no other I2C devices can be connected.

The actual sensor is tiny but a board is available from China with the I2C connections and power on a standard 0.1 inch header which makes it easily accessible.

AOSONG_AHT10_EN_DRAFT_0C

AHT20-DATASHEET-2020-4-16

REGISTER FILE

OFFSET		        FUNCTION		BIT
0			STATUS
1			HUMIDITY		H19 H18 H17 H16 H15 H14 H13 H12
2			HUMIDITY		H11 H10 H9  H8	H7  H6	H4  H4
3			HUMIDITY + TEMPERATURE	H3  H2	H1  H0	T19 T18 T17 T16
4			TEMPERATURE		T15 T14 T13 T12 T11 T10 T9  T8
5			TEMPERATURE		T7  T6	T5  T4	T3  T2	T1  T0

COMMANDS

SEQUENCE		FUNCTION
0xE1 0x08 0x00          INITIALISE AHT10
0xBE 0x08 0x00          INITIALISE AHT20
0xAC 0x33 0x00          TRIGGER MEASUREMENT
0xBA			RESET

STATUS REGISTER

BIT			FUNCTION
7			BUSY
6			MODE
5			MODE
4			?
3			CAL
2			?
1			?
0			?

MODE BITS		FUNCTION
00			NORMAL
01			CYCLE
10			COMMAND
11			COMMAND

AHT10 (English)

AHT10 (Chinese)

AHT20 (English)