7Semi I2C Qwiic SHT40 Temperature & Humidity Sensor

Overview

The module is based on the Sensirion SHT40 digital temperature and humidity sensor, a high-accuracy, low-power environmental sensor.

• Measures:

  • Temperature

  • Relative Humidity

   

• Provides fully calibrated digital output via I2C

• Designed for compact, high-precision sensing applications

It is part of Sensirion's next-generation SHT4x series, offering improved accuracy and reliability.

Working Principle

The SHT40 integrates two sensing mechanisms:

Temperature Measurement

• Uses a bandgap temperature sensor

• Provides precise temperature readings

• Also used for humidity compensation

Humidity Measureng element

Absorbs moisture changes capacitance

Converted into digital signal via internal ADC

Both signals are processed using factory calibration data, ensuring accurate output without external calibration.

Measurement Characteristics

Temperature

• Range: 40C to +125C

• Accuracy: 0.2C (typical)

Humidity

• Range: 0% to 100% RH

• Accuracy: 1.8% RH (typical)

Resolution

• High-resolution digital output (16-bit class)

Suitable for precision environmental monitoring.

Electrical Characteristics

• Supply voltage: 1.08V to 3.6V

• Typical current consumption:

  • ~0.4 eurement)

   

Extremely low power ideal for battery-powered devices.

Communication Interface

• Interface: I2C (two-wire digital communication)

• Fixed I2C address: 0x44

• Fast communication with simple command structure

No need for complex register handling (command-based operation).

Internal Features

Fully Calibrated Output

• Factory calibration stored in sensor

• Direct output in:

  • C (temperature)

  • %RH (humidity)

   

Integrated Heater

• Built-in micro-heater

• Used for:

  • Removing condensation

  • Self-diagnostics

   

High Repeatability

• Consistent reading

Fast Measurement Time

• Typical measurement time: ~110 ms

Qwiic / STEMMA QT Compatibility

Plug-and-Play I2C Connectivity

• Uses 4-pin JST SH connector

• Pins:

  • VCC

  • GND

  • SDA

  • SCL

   

Enables:

• Easy daisy-chaining

• No soldering required

Physical Characteristics

• Sensor size: ~1.5 1.5 0.5 mm (IC)

• Breakout: mini form factor

• Designed for compact embedded systems

Environmental Characteristics

• Wide operating range:

  • Temperature: 40C to +125C

  • Humidity: 0100% RH

   

• Simplifies integration with microcontrollers

Fast & Stable Output

• Quick response to environmental changes

• Stable readings with minimal noise

Humidity Compensation

• Temperature automatically compensates humidity readings

Heater Usage

• Can periodically activate heater to:

  • Prevent moisture buildup

  • Improve long-term stability

   

Limitations

• Measures relative humidity only

• Sensitive to:

  • Condensation (without heater use)

  • Chemical contamination

   

• Requires airflow for accurate readings

Breakout Board Role (7Semi)

The mini breakout board:

• Provides:

  • Voltage compatibility

  • I2C interface access

   

• Includes:

  p

Summary

The 7Semi SHT40 mini breakout is a high-precision environmental sensor module that:

• Measures temperature and humidity with high accuracy

• Uses capacitive + bandgap sensing technology

• Provides fully calibrated digital I2C output

• Offers very low power consumption

• Includes heater and fast response capability

• Is optimized for compact, reliable environmental monitoring systems