AHT10 temperature and humidity sensor: specs and pinout
Digital I2C temperature and relative-humidity sensor (ASAIR/Aosong AHT10 chip) on a breakout. The manual covers the bare chip; the breakout is not documented.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage (VDD) | 1.8 V to 3.6 V (typ 3.3 V) | source Page 2, Table 2 Electrical characteristics |
| Absolute maximum VDD to GND | -0.3 V to 3.6 V | source Section 4.1 Table 6 |
| Interface and address | I2C, 7-bit address 0x38 | source Page 2 Table 2; Section 5.3 |
| Humidity range / resolution / accuracy | 0-100 %RH (extended range; normal range 0-80 %RH, readings drift outside it); 0.024 %RH resolution; +/-2 %RH typ at 25 C and VDD 3.3 V | source Page 2, Table 1 and footnotes 1 and 3 |
| Temperature range / resolution / accuracy | -40 C to 85 C (extended range; operating range limited to -40 C to 80 C); 0.01 C resolution; +/-0.3 C typ | source Page 2, Table 3 and footnote 3 |
| Supply current | 0.25 uA max in sleep; 320 uA typ while measuring | source Page 2, Table 2 |
| Power-up to ready | up to 20 ms (wait before sending commands) | source Section 5.1 |
| Measurement time | wait about 80 ms after the measure command (0xAC) | source Section 5.3 read flow |
| I2C clock | 0-100 kHz standard mode; 0-400 kHz fast mode | source Table 8 |
| Recommended measurement interval | once every 2 s to limit self-heating | source Section 2.4 |
Power
| Value | Source | |
|---|---|---|
| Supply | 1.8 V to 3.6 V | source Page 2, Table 2 |
| Current | 320 uA typ while measuring; 0.25 uA max sleep | source Page 2, Table 2 |
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.
These are the chip's 6 DFN pins. The breakout board (header order, regulator, pull-up resistors) is not covered by an official document.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| 1 | ADR | Described in Table 5 as connected to power ground | source Section 3 Table 5, Figure (top view) | |
| 2 | SDA | Serial data, bidirectional | source Section 3 Table 5, Figure (top view) | |
| 3 | SCL | Serial clock, bidirectional | source Section 3 Table 5, Figure (top view) | |
| 4 | VDD | Supply voltage | source Section 3 Table 5, Figure (top view) | |
| 5 | GND | Ground | source Section 3 Table 5, Figure (top view) | |
| 6 | NC | Left floating | source Section 3 Table 5, Figure (top view) |
Build with it
Project ideas for the AHT10 temperature and humidity sensor. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Temperature and humidity on an OLED: The ESP32's 3.3 V sits inside the AHT10's 1.8-3.6 V range, and both parts are I2C. The AHT10 answers at address 0x38.
- Humidity and temperature serial logger: One reading every few seconds suits the manual's advice of at most one measurement per 2 s.
- Mini weather station: The AHT10 supplies humidity and temperature and the BMP280 supplies pressure; they use different I2C addresses on the same two wires.
- Temperature and humidity web page: The NodeMCU is a 3.3 V Wi-Fi board with I2C, matching the AHT10's 1.8-3.6 V supply.
Common mistakes
- Powering the chip from 5 V: the supply range is 1.8-3.6 V and the absolute maximum VDD is 3.6 V (source: link, Table 2 and Table 6). Whether the breakout has a regulator is not in any official document
- No pull-ups on SDA and SCL: the manual shows pull-up resistors (example 4.7 kOhm) to VDD and a 10 uF decoupling capacitor near the sensor (source: link, Section 3.3 and Section 3.1)
- Reading too fast: measuring more often than every 2 s warms the sensor and skews temperature (source: link, Section 2.4)
Not covered by the official source
- Values are from pages 1-8 of the maker's manual V1.2 (Chinese-language original).
- Breakout board (regulator, pull-ups, header order, 5 V input) is not documented by any official source.
- Table 5 names the ADR pin 'connected to power ground'; its behaviour is not described further.
Sources
- link (Aosong/ASAIR AHT10 technical manual, Chinese, V1.2)