Fermion MEMS Formaldehyde HCHO Gas Detection Sensor

What this sensor is

The Fermion MEMS Formaldehyde (HCHO) Gas Detection Sensor (DFRobot) is a compact gas sensor designed to detect:

• Formaldehyde (HCHO) a harmful indoor pollutant

It's commonly used in:

• Air purifiers

• Indoor air quality systems

• HVAC systems

Core Concept (VERY IMPORTANT)

This is a MEMS-based gas sensor

• Detects formaldehyde concentration changes

• Outputs analog signal (not direct ppm display)

Important:

• It provides qualitative measurement (trend), not highly accurate lab-grade values

Key Specifications

• Gas detected: Formaldehyde (HC/strong

• Output: Analog voltage

• Operating voltage: 3V 5V

• Current consumption: <20 mA

• Size: ~13 13 2.5 mm

• Lifespan: ~3 years

Working Principle

• Uses MEMS gas sensing technology

• Formaldehyde gas changes sensor resistance

• Circuit converts it to analog voltage output

More HCHO larger signal change

Pinout (Typical Fermion Breakout)

• VCC 3.3V / 5V

• GND Ground

• AOUT Analog output

Connect AOUT Arduino analog pin (A0)

Key Features

•  

• Low power consumption

• Compact MEMS design

• Easy to integrate with Arduino

Applications

• Indoor air quality monitoring

• Furniture emission detection (formaldehyde from wood/paint)

• Air purifiers

• HVAC systems

• Smart environment monitoring

Important Notes (VERY IMPORTANT)

1. Not highly accurate

• Provides relative readings, not exact ppm

• For precise measurement use electrochemical sensors

2. Cross-sensitivity

• May respond to:

  • Alcohol

  • VOC gases p

   

  4. Environmental sensitivity

  Avoid:

  • High humidity

  • Corrosive gases

  • Silicone vapors

   

  MEMS vs Electrochemical HCHO Sensors

  When to use this

  Use this sensor if you want:

  • Low-cost formaldehyde detection

  • Air quality trends

  • DIY air monitoring projects

   

  When NOT to use

  Avoid if:

  • You need accurate ppm measurement

  • Medical / safety-critical applications

   

  or = formaldehyde presence detector (trend-based) Good for IoT projects, not lab-grade accuracy

  Pro Tip (Very Useful)

  Best combo for air quality system:

  • SHT41 Temperature + Humidity

  • ENS160 / SGP40 VOC

  • HCHO sensor Formaldehyde

   

  Together