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Carbon dioxide is a critical indicator of indoor air quality that can affect human cognitive
abilities and well-being. The SCD40/SCD41 are Sensirion's next-generation miniaturized CO2 sensors, offering high precision and cost-effectiveness. These modules feature a 2.54mm pitch pin header interface for power supply and communication connections. On-chip temperature and humidity compensation is achieved through built-in sensors for humidity and temperature measurement. The SCD40/SCD41 can intelligently regulate indoor ventilation systems based on C02 concentration levels, thereby maintaining a healthy and efficient environment with low C02 levels over time. This makes the SCD40/SCD41 ideal for applications focused on improving indoor air quality.
Features
Specifications
What's in the box?
1 x SCD40 sensor
Resources
The SCD40 and SCD41 are high-performance "True" CO2 sensors. Unlike cheaper VOC sensors that estimate CO2 levels, these use photoacoustic technology to measure the actual concentration of CO2 in the air.
The setup for the Raspberry Pi 5 (and older models) involves the I2C interface.
1. Hardware Connections (I2C)
The module communicates via I2C, which only requires four wires. Note that while these sensors can handle 5V power, the Raspberry Pi's logic pins are 3.3V. Ensure your module's I2C lines are compatible (most breakout boards from Adafruit/PiShop have 3.3V regulators/shifters built-in).| Sensor Pin | Raspberry Pi Pin | Physical Pin # |
| VIN / VCC | 3.3V (or 5V if supported) | Pin 1 (3.3V) or Pin 2 (5V) |
| GND | Ground | Pin 6 |
| SCL | I2C Clock (GPIO 3) | Pin 5 |
| SDA | I2C Data (GPIO 2) | Pin 3 |
2. Enable I2C on the Raspberry Pi
Before you can read the data, you must enable the I2C port:Run sudo raspi-config in the terminal.
Navigate to Interface Options > I2C.
Select Yes to enable it.
Reboot your Pi.
(Optional) Check if the sensor is detected by running i2cdetect -y 1. The SCD4x should appear at address 0x62.
