CO2 Sensor SCD4x
Breaking the Size Barrier in CO2 Sensing
The SCD4x is Sensirion’s next generation miniature CO2 sensor that offers an unmatched price-to-performance ratio. Tape and reel packaging combined with its SMD assembly processing make the SCD4x ideal for high-volume applications.
This sensor builds on the photoacoustic sensing principle and Sensirion’s patented PASens® and CMOSens® Technology to enable unmatched small sensor size combined with high performance. SMD compatibility and the small footprint allow cost- and space-effective integration to boost freedom of design for customers. The integrated best-in class humidity and temperature sensor enables superior on-chip signal compensation and addition RH and T outputs. Finally, the large supply voltage (2.4 V – 5.5 V), the robustness towards external stresses and the adjustable power consumption make the SCD4x the perfect fit for varying customer needs.
Features and Applications
Features | Applications |
|
|
|
|
|
|
|
|
|
|
|
|
|
Sensor Specifications
Name | Accuracy | Specified Range | Low Power Single Shot | Available packaging type / size | Package Size | Datasheet | Buy |
---|---|---|---|---|---|---|---|
SCD40 | ±(50 ppm + 5 % of reading) | 400 ppm – 2'000 ppm | no | Tape on Reel / 600 | 10.1 x 10.1 x 6.5 mm3 | Download | Coming soon |
SCD41 | ±(40 ppm + 5 % of reading) | 400 ppm – 5'000 ppm | yes | Tape on Reel / 600 | 10.1 x 10.1 x 6.5 mm3 | Download | Coming soon |
SCD4x Features and Benefits
Features | Benefits |
---|---|
Smallest form factor | Highest freedom of design |
Integrated RH + T sensor | Lowest integration and product cost |
Reflow solderable (SMD) | Space and cost-effective assembly |
Large supply voltage range | No external circuitry required, no energy loss |
Superior mechanical robustness | Accurate readings right after assembly |
Typical NDIR CO2 Sensor vs. SCD4x
Features | Typical NDIR CO2 Sensor | SCD4x CO2, RH + T Sensor |
---|---|---|
High selectivity | ![]() | ![]() |
Small size | ![]() | ![]() |
Additional sensor Outputs | ![]() | ![]() |
Cost-effective Assembly | ![]() | ![]() |
Mechanical robustness | ![]() | ![]() |
Cost-effective BOM | ![]() | ![]() |
Start Evaluating the SCD4x Today
The SEK-SCD41 evaluation kit has been designed for easy and cost-efficient evaluation of Sensirion’s SCD4x CO2 sensor. The kit contains a SCD41 mounted on a development board with a JST connector and through-hole pins. The included adapter cable (JST-Ethernet) connects to the SEK-SensorBridge for easy evaluation of the sensor via the SEK-ControlCenter viewer software. Finally, the kit contains a 4-pin jumper wire cable that enables fast prototyping, e.g. through integration into existing platforms (like Arduino, Raspberry Pi, etc.).
More information (documentation, drivers, tutorials, etc.) can be found here: www.sensirion.com/my-scd-ek
Compile your own environmental sensing evaluation kit at: www.sensirion.com/sek

Efficient Ventilation Helps to Reduce the Risk of Virus Transmission
Pupils are back in schools all over the world. Despite the coronavirus pandemic, they are sitting side by side in closed rooms for several hours. Of course, this raises concerns about virus transmission.Tiny droplets (known as aerosols) are emitted not only when people cough or sneeze, but also during normal breathing and speech. These aerosols may contain viruses, which is why frequent and effective ventilation is more important than ever. The more fresh air there is in a closed room, the less exhaled air which may contain viruses.
Various solutions for regular and effective ventilation in enclosed rooms are currently being tested. In Germany, for example, modules equipped with CO2 sensors were used to measure air quality in school classrooms. The advantage: a CO2 warning system is easy to use, intuitively understandable thanks to the traffic light system, and measures with high accuracy. A CO2 warning system ensures regular and effective ventilation, so instructors and pupils can work together calmly and with a little more security and freedom from worry. In addition to reducing the risk of transmitting viruses such as COVID-19, CO2 reduction measures also increase concentration capacity – another positive effect.
PASens® Technology
PASens® Technology is based on the photoacoustic sensing principle. The photoacoustic sensing principle allows extreme miniaturization of the CO2 sensor without compromising sensor performance due to the fact that the sensor sensitivity is independent of the optical cavity size. The reduced size and the smaller number of integrated components result in a highly price-efficient BOM structure. Thanks to the miniaturizing and the economical BOM structure of these new CO2 sensor, the SCD4x will open up numerous possibilities for a whole new set of products and applications.
Click here to learn more about the measurement principle and key features of PASens® Technology.

Environmental Sensing
Environmental conditions have a major impact on our well-being, comfort, and productivity. Sensirion’s sensor solutions provide detailed and reliable data on key environmental parameters such as humidity, temperature, volatile organic compounds (VOCs), particulate matter (PM2.5), formaldehyde and CO2. Environmental Sensing opens up new possibilities to create smarter devices that improve our comfort and well-being as well as increase energy efficiency in a wide variety of applications.
We accompany you through the entire product development process, from the initial idea to product launch and beyond. Our expertise ranges from prototype construction, design-in support and use-case development to inline testing at the mass production stage.