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Home / Computer Hardware, Monitors & Peripherals / GY-21-HTU21 Sensor Module for Moisture and Humidity with I2C Interface

Attributes

Brand -
Category Electronic Components / Maker DIY / Computer Hardware, Monitors & Peripherals
Origin -
Interface I²C (Inter-Integrated Circuit)
Operating Voltage 3.3V to 5V DC
Humidity Range 0% to 100% RH
Temperature Range -40°C to +125°C
Humidity Accuracy ±2% RH (typical)
Temperature Accuracy ±0.3°C (typical)
Response Time 5 Seconds (tau63%)
Board Dimensions 25mm x 20mm x 5mm
Sensor Chip HTU21D
Current Consumption 150μA during measurement

5 reviews

A

Anonymous

Mar 02, 2026

Rating: 4/5

Good accuracy, slight delay

The sensor is accurate but there is a small delay in reading updates. For most projects, this is negligible. Good value for money.

A

Anonymous

Feb 27, 2026

Rating: 4/5

Solid Performance

Does exactly what it says. Humidity readings stabilize quickly after power on. Would recommend for indoor monitoring.

A

Anonymous

Feb 26, 2026

Rating: 5/5

Reliable Module

Bought five of these for a classroom project. All worked out of the box. Pinout is clearly labeled which helps beginners.

A

Anonymous

Feb 18, 2026

Rating: 5/5

Perfect for Arduino Weather Station

Works flawlessly with my Arduino Uno. The I2C library was easy to find and implement. Readings seem consistent with my home thermometer.

A

Anonymous

Jan 22, 2026

Rating: 5/5

Compact and Easy

Small form factor fits nicely in my enclosure. Voltage regulation on the board allows 5V logic which is convenient.

5 FAQ

Q: Does it come with headers?

A: Yes, the module usually comes with pre-soldered pin headers for easy breadboard use.

Q: Is there a library for ESP32?

A: Yes, there are multiple open-source libraries available for ESP32 that support the HTU21D sensor.

Q: Is this compatible with Raspberry Pi?

A: Yes, it works with Raspberry Pi using the I2C pins. Ensure you enable I2C in the configuration.

Q: Can I use this outdoors?

A: The module itself is not waterproof. You should place it in a weatherproof enclosure if used outside.

Q: What is the I2C address?

A: The default I2C address is typically 0x40. Please refer to the datasheet for configuration options.

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