Description
Reviews
| Brand | - |
| Category | Robotics / STEM Teaching Tools / Sensors |
| Origin | - |
| Model Number | AHT21B |
| Measurement Range (Temperature) | -40°C to +85°C |
| Measurement Range (Humidity) | 0% to 100% RH |
| Accuracy (Temperature) | ±0.3°C |
| Accuracy (Humidity) | ±2% RH |
| Communication Interface | I2C |
| Supply Voltage | 2.2V to 5.5V DC |
| Response Time | < 8 seconds |
| Package Type | SMD Module |
| Application | HVAC, Smart Home, Industrial Monitoring |
Anonymous
Mar 31, 2026
Rating: 4/5
Good value, fast shipping
The module works as described. Humidity response is quick. Only giving 4 stars because the documentation could be slightly more detailed regarding register maps, but standard libraries work fine.
Anonymous
Mar 26, 2026
Rating: 5/5
Highly recommended
This is my go-to sensor for any project requiring environmental data. The integration is seamless, and the data consistency over time is impressive.
Anonymous
Mar 24, 2026
Rating: 4/5
Solid performance
Works right out of the box. The soldering pads are large enough for hand soldering if you don't have a reflow oven. Readings match my expensive benchtop unit within expected tolerance.
Anonymous
Mar 22, 2026
Rating: 5/5
Low power consumption
Great for battery-powered IoT devices. The sleep mode current is incredibly low, allowing my device to run for months on a single coin cell.
Anonymous
Mar 22, 2026
Rating: 5/5
Perfect for agricultural monitoring
We deployed twenty of these in our prototype greenhouse system. They handle the high humidity environment well without drifting. Very reliable for the price point.
Anonymous
Mar 19, 2026
Rating: 5/5
Excellent precision for hobby projects
I integrated this sensor into my home weather station and the readings are consistently accurate compared to my calibrated reference meter. The I2C communication is stable and easy to implement with Arduino.
Q: Does this module come with a protective filter?
A: The standard module includes a basic dust filter. For environments with heavy particulate matter or corrosive gases, we recommend adding an external membrane filter.
Q: What is the maximum cable length for the I2C connection?
A: For standard I2C speeds (100kHz), we recommend keeping cables under 30cm for optimal reliability without pull-up resistor adjustments. For longer distances, consider using an I2C extender or buffer.
Q: Can I use 3.3V logic levels?
A: Absolutely. The sensor operates between 2.2V and 5.5V, making it directly compatible with both 3.3V and 5V microcontroller logic levels without a level shifter.
Q: How often should I calibrate this sensor?
A: The AHT21B is factory calibrated and typically maintains accuracy for years under normal operating conditions. Recalibration is generally only necessary if the sensor is exposed to extreme conditions beyond its specifications.
Q: Is this compatible with Raspberry Pi?
A: Yes, the AHT21B uses the I2C protocol which is fully supported by Raspberry Pi GPIO pins. You will need to enable the I2C interface in the raspi-config settings.
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