The SparkFun SGP40 Air Quality Sensor measures volatile organic compound (VOC) levels in indoor environments using Sensirion's CMOSens technology. The metal oxide (MOx) sensor with a temperature-controlled micro hotplate provides humidity-compensated air quality readings via I2C with Qwiic connectors for easy integration.

Rather than returning specific gas concentrations, the SGP40 outputs a digital value based on common indoor VOCs. Combined with Sensirion's VOC Index Algorithm, it detects the relative intensity of VOC events compared to average readings over a 24-hour period — think of it as an electronic nose for your room.

Key Features

• Sensirion SGP40 Sensor – MOx-based VOC detection with humidity compensation
• Qwiic / I2C Interface – Two Qwiic connectors for daisy-chaining; I2C address 0x59
• VOC Index Output – Processed output from 0–500 VOC Index points, plus raw signal (SRAW) 0–65535 ticks
• Fast Start-Up – Reliably detects VOC events in under 60 seconds; meets full specifications within 1 hour
• Low Power – 2.6 mA during continuous operation at 3.3 V; 34 μA idle with heater off
• Long-Term Stability – Robust against contaminating gases with low drift and minimal device-to-device variation

Specifications

• Operating Voltage – 1.7–3.6 V (typical 3.3 V via Qwiic)
• Current (Active) – 2.6 mA at 3.3 V
• Current (Idle) – 34 μA (heater off)
• I2C Address – 0x59
• Recommended Sampling Interval – 1 s (VOC Index); 0.5–10 s (SRAW)

Ideal For

• Indoor air quality monitoring
• Smart home and HVAC systems
• Environmental sensing projects
• Air purifier control and ventilation feedback

Package Contents

• 1× SparkFun SGP40 Air Quality Sensor (Qwiic)

Resources

• Hookup Guide
• SGP40 Datasheet (PDF)
• Schematic (PDF)
• VOC Index for Experts (PDF)
• SGP40 Design-In Guide (PDF)
• Arduino Library (GitHub)
• Python Package (GitHub)
• Hardware Design Files (GitHub)