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Reliably measure CO2 in indoor air:
World´s smallest selective CO2 sensors

Thanks to new energy standards and better insulation, homes and office buildings have become increasingly energy efficient. Here, active ventilation is necessary to maintain our well-being and productivity. At the same time, the indoor climate should be regulated in the most energy-efficient way possible. A decisive indicator of indoor air quality is its CO2 content.
Air exchangers and intelligent ventilation systems in commercial and residential applications use CO2 sensors. In addition, CO2 sensors play an essential role in monitoring indoor air quality and can therefore be integrated into indoor air monitors, air purifiers and smart thermostats.
SENSIRION's SCD4x are currently the world's smallest selective CO2 sensors.
Measuring only 10.1 x 10.1 x 6.5 mm³, they are smaller than a sugar cube. This makes them easy to integrate into compact applications.
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The SCD40 and SCD41 components are reflow solderable. They can be processed quickly and conveniently using placement systems. This saves time and money in production.
Despite their tiny size, both CO2 sensors already have an integrated temperature and humidity sensor. The wide operating voltage range is 2.4 V to 5.5 V.
This allows you to save on additional external components such as a level converter.
With its accuracy of ±50 ppm, SCD40 is ideal for CO2 traffic lights, for example.
The SCD41 operates with an accuracy of ±40 ppm and offers an additional low-power mode. It is the perfect component for high quality ventilation systems and battery powered devices.
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The PASens® measuring principle
The extreme miniaturization of CO2 sensors is achieved by the unique PASens® technology. It is based on the photoacoustic measuring principle, which has been known since 1880, and has now been brought into this tiny format by SENSIRION.
Narrowband light matching the absorption bands of CO2 molecules is emitted into a predominantly closed measuring cell.
The CO2 molecules in the measuring cell absorb a part of the emitted light.
The more CO2 molecules there are in the measuring cell, the greater the absorbed energy.
Other molecules, however, do not absorb this light.
The absorbed energy stimulates the molecules to oscillate, which results in an increase in pressure in the cell due to the closed measuring cell.
The modulation of the light source causes a periodic pressure change in the measuring cell, which is measured by a microphone. The signal from the microphone thus serves as a measure of the number of CO2 molecules present in the measuring cell and is then

SCD40 | SCD41 | |
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Size | 10,1 x 10,1 x 6,5 mm³ | |
Measuring range CO2 | 0…40.000 ppm | |
Accuracy CO2 | ±(50 ppm +5 % v.Mw.) @400…2.000 ppm |
±(40 ppm +5 % v.Mw.) @400…5000 ppm |
Measuring range T | -10…60 °C | |
Measuring range RH | 0…100% | |
Operating voltage | 2,4 V…5,5 V | |
Power consumption | 12 mA (Measurement rate = 5 s) 2,5 mA (Measurement rate = 30 s) |
12 mA (Measurement rate = 5 s ) 2,5 mA (Measurement rate = 30 s) 0,4 mA (Measurement rate = 5 min) |
Data sheet | SCD4x |
Get started now with the SENSIRION starter kit and GLYN-SUPPORT.
With the SEK-SCD41 sensor in combination with the SEK-SensorBridge you have a complete plug-and-play solution. With the associated viewer software, called ControlCenter, you can display and record the measured values of the sensors directly on your PC.


The SEK-SCD41 sensor can alternatively be connected to an Arduino or Raspberry PI via the included jumper cables. The corresponding software is available free of charge and completely directly from SENSIRION. As a third option, you can solder the SCD41 Development Board to your own application using the enclosed pin headers and thus test the performance of the sensor.
Rely on 20 years of sensor expertise and start your development with GLYN-SUPPORT.
We will be happy to answer your questions personally - by phone or email.
Be one of the first to start and secure your sample and starter kit today.