The SCD40 is a compact photoacoustic CO2 sensor that combines a carbon dioxide detector with integrated temperature and humidity sensing on a single chip using Sensirion's PASens® and CMOSens® technology . It's an ideal choice for indoor air quality monitoring, ventilation control, and scientific experiments .
| Parameter | Value |
|---|---|
| CO2 Range | 0 to 40,000 ppm (specified 400-2000 ppm) |
| CO2 Accuracy | ±(50 ppm + 5% m.v.) |
| Temperature Range | -10°C to +60°C |
| Temperature Accuracy | ±0.8°C (15-35°C) |
| Humidity Range | 0 to 95%RH (non-condensing) |
| Humidity Accuracy | ±6%RH (1535°C, 2065%RH) |
| I2C Address | 0x62 |
| Dimensions | 10.1 x 10.1 x 6.5mm |
Photoacoustic Sensing Principle - Direct and accurate CO2 concentration measurement
Integrated Sensor Fusion Builtin SHT4x sensor compensates readings for ambient conditions
I2C Digital Interface Simple 2wire communication with built-in CRC verification
Multiple Measurement Modes Supports periodic, lowpower, and single-shot commands
Automatic SelfCalibration Routine that automatically adjusts to its environment over time
Factory Calibrated - Ready to use with calibration certificate from Sensirion
√ Multiple Qwiic/STEMMA QT ready breakout boards available
√ Supports ESPHome and ESP-IDF via community components
The SCD40 communicates via I2C and can be powered directly from 3.3V or 5V . Breakout boards often include onboard voltage regulation and level shifting for easy integration . It supports different measurement modes:
Easy Integration - Works with many microcontroller platforms including Arduino and Raspberry Pi
ReadytoUse Factory calibrated and includes automatic selfcalibration
√ Commonly available in breakout board form factor
√ Compatible with standard I2C libraries across various platforms
√ Onboard signal compensation enhances accuracy
Sensor not communicating:
Inaccurate readings: