7Semi SFA40 Formaldehyde (HCHO) Sensor (0-2000ppb, ±20ppb) with I2C Qwiic interface

The 7Semi SFA40 Formaldehyde Sensor Breakout is a compact digital air-quality sensing module designed for accurate detection of formaldehyde (HCHO) in indoor environments. Built around the SFA40 electrochemical sensor, it provides formaldehyde measurements from 0 to 2000 ppb through a digital I2C interface, with a typical accuracy of +/-20 ppb or +/-20% of the measured value, whichever is greater, within the specified 0–200 ppb accuracy range.

The sensor offers excellent selectivity to formaldehyde, with only 0.3% typical cross-sensitivity to ethanol under specific conditions. Integrated relative humidity and temperature sensing enables automatic compensation of environmental effects, helping maintain reliable formaldehyde measurements under changing indoor conditions. Temperature and relative humidity readings are also accessible through the I2C interface.

Designed for convenient integration, the board features dual Qwiic-compatible connectors, breakout connections for VIN, GND, 3V3, SCL, and SDA, and an onboard power indicator. The compact 29 × 21mm PCB is suitable for indoor air-quality monitors, air purifiers, HVAC systems, smart buildings, IoT devices, and environmental monitoring applications.

Key Features

• Accurate Formaldehyde Detection: Measures formaldehyde (HCHO) concentrations from 0 to 2000 ppb digital output.

• High Measurement Accuracy: Provides typical accuracy of +/-20 ppb or +/-20% of the measured value, whichever is greater, over the specified 0–200 ppb range.

• Temperature and Humidity Compensation: Uses integrated relative humidity and temperature sensing to compensate formaldehyde measurements for changing environmental conditions.

• Digital I2C Communication: Supports 100kHz and 400kHz I2C communication with a fixed 7-bit address of 0x5D.

• Fast Measurement Updates: Provides new measurement data approximately every 0.5 seconds during continuous operation.

• Long Sensor Lifetime: Designed for more than six years of operation under standard environmental conditions.

• Dual Qwiic Connectivity: Includes two onboard Qwiic-compatible connectors for convenient I2C wiring and daisy-chaining.

• Power Status Indicator: Features an onboard PWR LED for visual indication of board power.

• Compact Breakout Design: Provides a 29 × 21mm PCB with additional VIN, GND, 3V3, SCL, and SDA connections for flexible integration.

Items included

• 1 × 7Semi SFA40 Formaldehyde Sensor I2C Qwiic Breakout Board

Note: Qwiic cable not included.