SmartElex HTU21D-F Temperature and Humidity Sensor with Breakout Board

Overview

The SmartElex HTU21D-F Sensor Breakout is a digital temperature and relative humidity sensor module based on the HTU21D-F CMOSens sensor.

• Measures:

  • Temperature

  • Relative Humidity

   

• Provides fully calibrated digital output via I2C

• Designed for accurate environmental sensing in embedded systems

Acts as a modern replacement for older sensors like SHT15

Working Principle

• Humidity sensing: Capacitive polymer element changes with moisture

• Temperature sensing: Integrated bandgap sensor

Internal process:

• Signal conditioning

• High-resolution ADC conversion

• Digital compensation

Outputs linear, calibrated digital data direct)

Measurement Characteristics

Temperature

• Range: 30C to +90C

• Accuracy: 1C (typical)

Humidity

• Range: 0% to 100% RH

• Optimized Accuracy Range: 5% to 95% RH

• Accuracy: 2% RH (typical)

Resolution & Performance

• High-resolution digital output (1214 bit typical depending on mode)

• Fast response with stable readings

• Good long-term stability

Electrical Characteristics

• Operating Voltage (sensor): ~1.5V 3.6V

• Breakout Support: 3.3V / 5V compatible (with regulator & level shifting)

Power Consumption

• Very low (suitable for battery-powered devices)

Communi/strong> 0x40

Simple 2-wire communication:

• SDA (data)

• SCL (clock)

Breakout Board Features

• Built-in:

  • 3.3V voltage regulator

  • I2C level shifting circuit

   

• Compact PCB (~18 16 mm)

• Optional:

  • PTFE filter (protects sensor from dust/moisture)

   

Ensures safe and easy interfacing with 3.3V & 5V systems

Internal Architecture

• Capacitive humidity sensing element

• Temperature sensor

• ADC (high resolution)

• Digital signal processor

• Calibration memory

Functional Features

• Factory calibrated and linearized output

• Temperature compensation for humidity readings

• Low noise measurement

• Stable long-term operation

Functional Behavior

Relative humidity Outputs:

• Digital values via I2C

Supports:

• Periodic measurement

• On-demand measurement

Key Technical Features

• High accuracy (2% RH, 1C)

• Digital I2C interface

• Fully calibrated output

• Compact breakout design

• Wide humidity range (0100%)

• Built-in regulator & level shifting

• Low power consumption

Advantages

• Better accuracy than basic sensors (e.g., DHT series)

• Easy integration via I2C

• Stable and reliable readings

• Small size and low power

• Suitable for IoT and embedded systems

Limitations

• Not designed for extreme industrial environments

• Requires protection in:

  • Condensing environments

  • Dust-heavy areas

   

• Slightly lower accuracy pplications

  • Weather monitoring systems

  • Indoor air quality monitoring

  • IoT environmental sensing

  • Smart home automation

  • Data logging systems

  • HVAC monitoring

   

  Technical Summary

  The HTU21D-F breakout is a reliable digital temperature & humidity sensor module that:

  • Provides accurate, calibrated environmental data

  • Uses I2C for simple integration

  • Offers a good balance of accuracy, cost, and power efficiency

   

  Best suited for:

  • General-purpose environmental sensing

  • IoT and embedded applications

  • Moderate accuracy requirements