SHT31-D High-Accuracy Humidity Sensor
Lab-grade Sensirion sensor for precision climate logging.
Wiring & code for
SHT31 practical reference
A high-accuracy I2C sensor from Sensirion used in HVAC and data-logging projects where DHT-series drift is unacceptable. The SHT31-D combines a capacitive humidity sensor and a bandgap temperature sensor on a single chip with factory calibration and onboard signal conditioning, delivering lab-grade accuracy and long-term stability that far exceeds cheaper hobbyist sensors like the DHT11/DHT22 — ideal for precision climate control, weather stations, and any project where measurement drift over time is a real concern.
Key specifications
- Sensor type: Sensirion SHT31-D capacitive humidity + bandgap temperature sensor
- Operating voltage: 2.4V–5.5V DC
- Operating current: ~1.5 µA idle, ~600 µA during measurement (very low average power)
- Humidity accuracy: ±2% RH typical (0-100% RH range)
- Temperature accuracy: ±0.2°C typical (-40°C to +125°C range)
- Response time: ~8 seconds (humidity, 63% response)
- Interface: I2C, up to 1MHz (fast mode plus)
- I2C address: 0x44 (default) or 0x45, selectable via the ADDR pin
- Additional feature: Built-in heater element for condensation removal and self-diagnostics
Pinout and connection notes
Add standard 4.7kΩ pull-up resistors on SDA/SCL if not already present on the breakout board. The ADDR pin lets two SHT31 sensors share a single I2C bus at different addresses, which is handy for differential measurements (e.g. indoor vs outdoor) in the same project.
- VIN: Power, 2.4–5.5V DC
- GND: Ground
- SCL: I2C clock line
- SDA: I2C data line
- ADDR: I2C address select — tie LOW for 0x44, HIGH for 0x45, useful when running two SHT31 sensors on the same bus
Integration checklist
- Confirm the exact part number and breakout-board revision.
- Verify supply voltage, current demand, logic levels, and signal direction against the datasheet.
- Check controller pin assignments and bus address or interface mode against the example code.
- Power up with external loads disconnected, then test signals before full integration.
- If readings or communication fail, check power and ground first, then pin mapping, interface settings, and library initialization.
Troubleshooting and reproducibility
Record the board used, wiring, library/version, supply arrangement, and measured behavior. Use the selected board-specific wiring example as the source of truth. Never assume visually similar modules share identical voltage tolerance or pin order.