SCD40 I2C CO Temperature & Humidity Sensor Breakout Module - 7Semi

What this module is

The SCD40 CO2, Temperature and Humidity Sensor Breakout I2C is a 3-in-1 environmental sensor that measures:

• CO (Carbon Dioxide)

• Temperature

• Humidity

It's based on Sensirion's SCD40 sensor, using photoacoustic (NDIR-like) technology for accurate CO sensing.

Key Specifications

• CO range: 400 ppm up to 40,000 ppm (best accuracy: 4002000 ppm)

• Accuracy: (4050 ppm + 5%)

• Interface: I2C (easy for Arduino/ESP32/RPi)

• Operating voltage: ~3.3V

• Power consumption:

  • ~17 mA (fast measurement)

  < Relative Humidity

  Key Features

  • True CO sensing (not eCO) more accurate than MQ-series

  • Factory calibrated plug & play

  • Low power ideal for battery IoT

  • Compact size easy to embed

  • Long-term stability minimal recalibration needed

   

  Pinout (Typical)

  • VCC 3.3V

  • GND Ground

  • SDA I2C Data

  • SCL I2C Clock

   

  I2C address: usually 0x62

  Applications

  • Indoor air quality monitors

  Important Notes (very useful)

  • Not for outdoor harsh environments (best indoors)

  • Auto-calibration may shift readings if room never reaches fresh-air (~400 ppm)

  • Needs airflow exposure for accurate readings

   

  Why SCD40 is popular

  Compared to cheap sensors (like MQ135):

  • Much more accurate & stable

  • Gives actual CO ppm

  • Lower drift over time

   

  When you should use it

  Use this if you want:

  • Professional-quality air monitoring

  • Reliable CO data for