Adafruit Si7021 Temperature & Humidity Sensor Breakout Board
I2C temperature and humidity sensor breakout based on the Si7021. Works at 3.3 V or 5 V with onboard level shifting and pull-ups, suitable for weather stations and HVAC monitoring.
I2C temperature and humidity sensor breakout based on the Si7021. Works at 3.3 V or 5 V with onboard level shifting and pull-ups, suitable for weather stations and HVAC monitoring.
Board power input. Adafruit states the onboard regulator accepts 3 to 5 VDC and safely converts it down for the Si7021 breakout.
3.3V output from the onboard voltage regulator. Adafruit states up to 100 mA can be drawn from this output.
Common ground for power and logic.
I2C clock pin. Connects to the microcontroller I2C clock line. Adafruit states the fixed I2C address is 0x40.
I2C data pin. Connects to the microcontroller I2C data line. Adafruit states the fixed I2C address is 0x40.
STEMMA QT / Qwiic connector carrying the board I2C and power connections for plug-and-play chaining.
| Pin | Position | Type | Function | Voltage |
|---|---|---|---|---|
| Vin | Vin | Power | Board power input. Adafruit states the onboard regulator accepts 3 to 5 VDC and safely converts it down for the Si7021 breakout. | 3-5V input |
| 3v3 | 3v3 | Power | 3.3V output from the onboard voltage regulator. Adafruit states up to 100 mA can be drawn from this output. | 3.3V output, up to 100 mA |
| GND | GND | Ground | Common ground for power and logic. | |
| SCL | SCL | I2C | I2C clock pin. Connects to the microcontroller I2C clock line. Adafruit states the fixed I2C address is 0x40. | Logic level follows host/power wiring |
| SDA | SDA | I2C | I2C data pin. Connects to the microcontroller I2C data line. Adafruit states the fixed I2C address is 0x40. | Logic level follows host/power wiring |
| STEMMA QT | STEMMA QT | Unknown | STEMMA QT / Qwiic connector carrying the board I2C and power connections for plug-and-play chaining. | 3-5V board power, I2C signals |
Board power input. Adafruit states the onboard regulator accepts 3 to 5 VDC and safely converts it down for the Si7021 breakout.
3.3V output from the onboard voltage regulator. Adafruit states up to 100 mA can be drawn from this output.
Common ground for power and logic.
I2C clock pin. Connects to the microcontroller I2C clock line. Adafruit states the fixed I2C address is 0x40.
I2C data pin. Connects to the microcontroller I2C data line. Adafruit states the fixed I2C address is 0x40.
STEMMA QT / Qwiic connector carrying the board I2C and power connections for plug-and-play chaining.
I2C · SPI · Single data line · 3.3 – 5 V · Breakout
Confirm the data interface matches your host board.
Module pins: Vin, 3v3, GND, SCL, SDA. Schematik maps them to your board in the app.
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