Accurately measure indoor formaldehyde (CH2O/HCHO) levels with this low-power, Qwiic-enabled SFA40 sensor from Sensirion.

The SparkFun SFA40 Qwiic Formaldehyde Sensor is a unique indoor gas sensor that measures low concentrations of formaldehyde (CH2O/HCHO) with excellent accuracy, even in the presence of other similar gases. The SFA40 communicates over I2C, so we put it on this Qwiic breakout to easily integrate it into a Qwiic circuit with no soldering necessary.

High-Accuracy Environmental Sensing

The SFA40 from Sensirion is an electrochemical sensor that maintains accurate formaldehyde measurements in environments that have other common indoor gases such as ethanol or nitrogen dioxide. This sensor also comes pre-calibrated with a unique manufacturer serial number for easy identification. To ensure your readings are as precise as possible, the SFA40 provides several key performance benefits:

• Wide Measurement Range: Detects formaldehyde gas concentrations from 0 to 2000 parts per billion (ppb).
• High Accuracy: Delivers measurements within ±20 ppb or ±20% of the total measured value, whichever is larger.
• Low Cross-Sensitivity: Highly resistant to interference, with a cross-sensitivity to ethanol of just 0.3%.
• Environmental Compensation: An integrated temperature and humidity sensor automatically adjusts for changing ambient conditions.

Operation and Qwiic Integration

While the SFA40 requires a 10-minute initialization period before it measures gas concentrations within its stated specifications, it responds to changes in under two minutes once properly warmed up. It also operates highly efficiently, consuming an average of just 80µA at 3.3V. This low power draw makes it an excellent choice for continuous monitoring thanks in part to its operational lifetime of over six years.

For hardware connections, dual Qwiic connectors offer a simple, daisy-chainable I2C interface to your main system. For a more permanent setup, a standard 0.1-inch spaced plated through-hole (PTH) header breaks out the power and I2C pins for a soldered connection. This breakout gives you a reliable, long-lasting way to track formaldehyde levels without complicated wiring.

Features & Specs:

• SFA40 Features
• Highly accurate formaldehyde (HCHO) sensor
• Low cross-sensitivity to common indoor gases
• Cross-sensitivity to ethanol: 0.3%
• Formaldehyde measurement range: 0 to 2000 ppb
• HCHO measurement accuracy: ±20 ppb or ±20%
• Low power: Average current consumption of 80µ[email protected]
• Start-up time: 10 min (until readings will be within specs)
• Long lifetime: > 6yrs
• Digital output over I2C
• Qwiic Breakout Features
• 2x Qwiic connectors
• 0.1"-spaced PTH Header (Power and I2C)
• Red power LED

Documentations:

• Schematic
• Board Dimensions
• Hookup Guide
• Datasheet (SFA40)
• SparkFun SFA40 Arduino Library
• GitHub Repository

Package Includes:

• 1 x SparkFun SEN-31669 Formaldehyde Sensor - SFA40 (Qwiic)