HTU21D Temperature and Humidity Sensor I2C

The HTU21D is an accurate digital sensor for humidity and temperature. Both values can be read out via the I2C interface. It is suitable for weather stations and other applications where humidity is measured.

Important: The module is marked for 3.3 V and has no voltage regulator. On a 5 V board such as the Arduino UNO, it needs the 3.3 V supply and a logic level converter for SDA and SCL.

I2C pull-up resistors: The module has two 4.7 kOhm resistors for SDA and SCL. They are not connected to VCC as standard. To activate them, the three solder pads on the top are connected with solder. With several sensors on the I2C bus, the resistors may only be active on one module.

Recommended Accessories:

• Logic Level Converter 2-Channel 5V / 3.3V
• Dupont Cable M-F 20cm 20 Pieces

Features:

• Measures humidity and temperature
• I2C interface
• Pull-up resistors can be enabled via three solder pads
• 2 mounting holes

Application Examples:

• Weather stations
• Monitoring humidity in rooms

Documentation:

• HTU21D Hookup Guide (SparkFun)
• Arduino library (GitHub)
• HTU21D datasheet (PDF)

Technical Data:

• Operating voltage: 3.3 V (marking), chip 1.5 V to 3.6 V
• Interface: I2C
• Connections: 3.3V, GND, SDA, SCL
• Humidity measuring range: 0 to 100 %RH
• Temperature measuring range: -40 °C to 125 °C
• Humidity accuracy: ±2 %RH
• Temperature accuracy at 25 °C: ±0.3 °C
• Dimensions: 15 × 15 × 2.7 mm
• Weight: 1.5 g

Scope of Delivery:

• 1× HTU21D temperature and humidity sensor I2C
• 1× Pin header 4x1