DFRobot
Gravity SFA40 Formaldehyde (HCHO) Sensor
· MPN: SEN0661
This Gravity-series module is a high-precision electrochemical sensor for monitoring formaldehyde (HCHO) in indoor air. It is built around Sensirion’s SFA40 ...
This Gravity-series module is a high-precision electrochemical sensor for monitoring formaldehyde (HCHO) in indoor air. It is built around Sensirion’s SFA40 sensing chip and is designed to selectively detect HCHO while reducing false readings from common household vapours such as alcohol or perfume.
An integrated SHT4x temperature and humidity sensor provides real-time environmental compensation, helping the module maintain stable readings across different indoor conditions. It can output HCHO concentration alongside temperature and humidity data for richer air-quality monitoring projects.
The Gravity I2C interface makes it straightforward to connect to Arduino-compatible boards and other microcontroller platforms. It suits smart home monitors, HVAC systems, air purifiers, ventilation controllers and experimental environmental sensing setups.
Included in the box are the Gravity: SFA40 HCHO Sensor and a Gravity 4-pin sensor cable.
Features:
- Sensirion SFA40 electrochemical formaldehyde sensing chip
- High sensitivity with detection threshold down to 20 ppb
- Measurement range up to 0–1000 ppb
- Extremely low cross‑sensitivity to ethanol (<0.3%) to prevent false alarms
- Integrated SHT4x sensor for temperature and humidity compensation
- Simultaneous output of HCHO concentration, temperature, and humidity
- Gravity I2C interface for easy integration with microcontroller platforms
- Suitable for smart home, HVAC monitoring, and environmental research
Specifications:
- Typical accuracy: ±20ppb or ±20% m.v (@0~200ppb measurement range)
- Wide measurement range: 0–1000 ppb
- Low cross-sensitivity: Cross-sensitivity to ethanol ＜0.3%
- Supply Voltage: 3.3–5V
- Operating Temperature: 0~50℃
- Operating Humidity: 10~90%R.H
- Operating Current: 80μA(Average@2Hz), 2mA(peak)
- Size: 32 * 22mm
A compact choice for makers and developers building indoor air-quality instruments, portable inspectors or automated ventilation responses.
Jargon buster
Plain-language definitions for the technical terms used above.
- Gravity
- Gravity is DFRobot’s plug-in connector system for sensors, motors and modules, using standard cables to reduce loose jumper wiring. It matters because Gravity-compatible parts can connect directly to these ports, while non-Gravity parts may need adapters or manual wiring.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
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Supplier page — dfrobot.com
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