The AGS02MA is a MOX-based TVOC sensor equipped with a miniature ADC chip that converts the readings into I2C for gas resistance output and parts-per-billion (ppb). This resistance can be correlated with ambient volatile organic compounds (TVOC) – higher ppb means more organic compounds in the air. It’s a simple sensor and doesn’t perform any additional filtering or calculations but it’s also inexpensive and small!

Please note: this sensor runs at 20KHz I2C which is lower than many chipsets like to do! We successfully ran this sensor on RP2040, ESP32 and ATmega328 (UNO) processors but other chips like SAMD21 and SAMD51 didn’t work as they don’t support 20KHz clock rate. Verify your board can perform 20KHz with an oscilloscope or logic analyzer before trying this sensor out! It will not work at 100KHz or 400KHz.

Two 10K pullup resistors are also required to wire this to an I2C bus, but it will work with 3V or 5V so no level shifting is required.

We do have Arduino library and CircuitPython code you can use to get started.

Specifications

• Operating Voltage: 3.3~5.5 VDC
• Operating Current: 28 5mA
• Sampling Period: 2s
• Preheating Time: 120s
• Operating Temperature: 050
• Operating Humidity: 0~95%RH
• Life Span: 5 years (@25 , clean air)
• Output Mode: I2C peripheral mode (30 kHz)
• Semiconductor sensor
• Measuring Range: 099999 ppb
• Standard Test Gas: Ethanol

Resources

• AGS02MA Datasheet