Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Sensor Type	Digital Relative Humidity and Temperature
Communication Interface	I2C (Inter-Integrated Circuit)
Operating Voltage	3.3V to 5.5V DC
Humidity Range	0% to 100% RH
Temperature Range	-40°C to +125°C
Humidity Accuracy	±2% RH (at 25°C)
Temperature Accuracy	±0.3°C (at 25°C)
Response Time	5 seconds (typical)
Package Type	DFN-6 Surface Mount with Breakout Board
Compatibility	Arduino, Raspberry Pi, ESP32, STM32

6 reviews

Anonymous

Mar 31, 2026

Rating: 5/5

Exceeded expectations

Bought this as an alternative to the more expensive SHT15 and honestly cannot tell the difference in performance for my use case. Fast shipping and well-packaged too.

Anonymous

Mar 29, 2026

Rating: 5/5

Perfect replacement for older SHT sensors

I needed a reliable sensor for my home weather station project and this HTU21D module works flawlessly. The I2C communication is stable, and the readings match my calibrated reference meter almost perfectly. Much easier to solder than the bare chip.

Anonymous

Mar 26, 2026

Rating: 4/5

Great accuracy for plant monitoring

Using this to monitor humidity in my indoor grow tent. It responds quickly to changes when I mist the plants. Only giving 4 stars because the breakout board pins are a bit close together for thick jumper wires, but otherwise excellent value.

Anonymous

Mar 20, 2026

Rating: 5/5

Stable long-term performance

I have three of these running in different rooms for over six months now. Zero drift observed and no connectivity issues. Highly recommended for any serious environmental monitoring application.

Anonymous

Mar 18, 2026

Rating: 5/5

Easy library support

Plug and play with standard Arduino libraries. I had data logging up and running in less than 20 minutes. The precision is noticeably better than the cheap DHT11 modules I used previously.

Anonymous

Mar 13, 2026

Rating: 4/5

Good value, small form factor

The module is tiny which is great for compact projects. Readings are consistent. Just make sure you have a 3.3V logic level if your microcontroller doesn't tolerate 5V on the data line, though the board seems tolerant.

5 FAQ

Q: Do you provide a sample code library for ESP32?

A: Yes, we host example code for ESP32, Arduino, and Raspberry Pi on our GitHub repository. The link is included in the downloadable datasheet provided on the product page.

Q: Can I use this with a 5V Arduino Uno directly?

A: Absolutely. The module operates between 3.3V and 5.5V, making it fully compatible with 5V systems like the Arduino Uno. No logic level shifter is required.

Q: Is there a waterproof coating on the sensor element?

A: The sensor element has a protective polymer cover that resists dust and partial water immersion, but the PCB itself is not waterproof. For humid environments, conformal coating on the board is recommended.

Q: What is the sampling rate of this sensor?

A: The HTU21D can perform up to 10 measurements per second, though for high-precision applications, we recommend a interval of 1 to 2 seconds to allow the sensor to stabilize.

Q: Does this module come with pull-up resistors for the I2C lines?

A: Yes, the breakout board includes integrated 4.7kΩ pull-up resistors on both SDA and SCL lines, so you can connect it directly to your microcontroller without external components.

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