A low-cost, highly accurate digital humidity and temperature sensor breakout board based on the Silicon Labs Si7021. Communicates over I²C with just two data lines, providing relative humidity and precise temperature readings for environmental monitoring projects.

The breakout includes built-in 4.7 kΩ pull-up resistors for I²C. If connecting multiple I²C devices on the same bus, you may want to disable these resistors to avoid conflicts.

Specifications

• Sensor – Silicon Labs Si7021
• Measurements – Relative humidity and temperature
• Interface – I²C
• Pull-Up Resistors – 4.7 kΩ (built-in, can be disabled)
• Connections – VCC, GND, SDA, SCL
• Board Dimensions – 15 × 15 mm (0.6″ × 0.6″)

Key Features

• High Accuracy – Precise humidity and temperature readings
• Simple I²C Interface – Only 4 pins to connect (VCC, GND, SDA, SCL)
• Built-In Pull-Ups – Ready to use out of the box
• Low Power – Ideal for battery-powered and data-logging applications

Ideal For

• Weather stations
• Environmental data logging
• Humidor and climate control systems
• IoT sensor networks

Package Contents

• 1× SparkFun Si7021 Humidity and Temperature Sensor Breakout

Resources

• Si7021 Datasheet (PDF)
• Hookup Guide (SparkFun)
• GitHub – Design Files and Example Code
• Schematic (PDF)
• Eagle Design Files (ZIP)