CDM7160/World leader in gas sensing innovation

Infra-Red(NDIR) CO2Sensor


Single IR light source, dual wavelength system ensures long-term stability in CO2 concentration output

Measurement of gas concentration by measuring the absorption ratio using two detector elements

CO2 sensors employing a single detector element typically utilize gas concentration correction software with the assumption that CO2 concentration in unoccupied space is around 400ppm. However, in an environment where many occupants are present at all times, or when CO2 gas concentration remains in excess of 400ppm, ambient CO2 concentration never falls to 400ppm, resulting in less accurate measurements due to inappropriate software corrections. The CDM7160 employs two detectors with different optical filters in front of each detector. One detector measures the intensity of transmitted infrared light of the wavelength region that is absorbed by CO2 gas (i.e. the CO2 absorption wavelength). The other detector measures the intensity of transmitted infrared light of the wavelength region that is not absorbed by CO2 (reference wavelength) and unaffected by CO2 concentrations, enabling effective correction of CO2 measurements.

Measurement principle of dual wavelength
Measuring infrared light intensities in two wavelength bands passing through each of the optical filters

The intensity of the optical light source may deteriorate over years of operation due to reduction of the infrared emittance or accumulation of dust on the optical components. CDM7160 measures infrared light intensity at the reference wavelength simultaneously, and calculates CO2 concentrations from the difference between light intensities at the CO2 absorption wavelength and the reference wavelength, resulting in reliable measurement of CO2 gas concentrations over a long period of operation.

Source of figure:
  • ・NIST Chemistry WebBook
  • ・NIST Standard Reference Database Number 69
  •  ( NIST: National Institute of Standards and Technology, U.S.Department of Commerce )

Reliable single light source, dual wavelength sensor

NDIR CO2 sensors are generally classified into three types:

  •   Single light source, single wavelength system
  •   Dual light source, dual wavelength system
  •   Single light source, dual wavelength system

The CDM7160 employs a single light source, dual wavelength system using two optical filters and measures intensities of the infrared lights at two different wavelength bands passing through each of the optical filters respectively in order to compensate for possible influences from dust or contamination, ensuring excellent long-term stability.

System Single light source, single wavelength sensor Single light source, dual wavelength sensor
Design Measures a single wavelength from a single light source Measures two wavelengths split from a single light source
  • ・Deterioration in reliability over time due to dirt and dust adhering to optical component surfaces
  • ・Short-term correction of drift by software required
  • ・Decreased accuracy when used in places where CO2 concentration remains high due to continued presence of occupants, such as small retail stores or hospitals
  • ・Excellent long-term stability achieved by utilizing the reference wavelength for drift compensation
  • ・Short-term correction of drift not required (*1)
  • ・High accuracy even when used in applications where people are continually present
  •    (*1) User recalibration is available for applications requiring higher accuracy.


Compact and Thin

Compact size with thickness of only 7.5 mm fits in well with low-profile environmental monitors or controllers.


Digital measured data are output to peripheral devices via two interfaces, UART or I2C

Measured CO2 concentration data can be output to a PC or external control device via UART (Universal Asynchronous Receiver Transmitter) interface, which is embedded into most of the latest microprocessors. The CDM7160 also incorporates an I2C (Inter-Integrated Circuit) interface for high-speed communications between the CO2 sensor and peripheral devices that are directly connected within a short distance. The I2C interface is not suitable for communication with remote devices. By connecting the CO2 sensor with an external microprocessor via the UART interface, measured data can be sent to or be received from a variety of control devices and equipment through the microprocessor. By utilizing a microcomputer with communication functions, CO2 concentration data can be transmitted wirelessly for remote control operations.


Peak current is only 60mA Enables downsizing of the external power supply circuit. Average current consumption during continuous
operation is only 10mA.

Technical Support

Technical Support

Customer and Technical Support

Based on the in-depth knowledge and expertise that Figaro has acquired through its 45+ years of experience in supplying high quality gas sensing solutions to global markets, Figaro provides sound and responsive technical support for application circuit design, selection of electronic components, detector housing design, gas detector manufacturing process, and other customer-specific technical questions.

Content-rich Technical Documents

Individual product data sheets, detailed technical information and application notes are available for customer’s reference.


From locations where measurement accuracy in constant 
operation is required (e.g. hospitals, libraries, and public facilities) to indoor 
air control systems which can be combined with Building
Energy Management Systems (BEMS) and Home Energy 
Management Systems (HEMS).

Suitable for a wide range of applications such as ventilation control equipment, air conditioning equipment, and small measuring devices for indoor environmental comfort and energy efficiency. Expected application includes input devices for environmental measurement in IoT and M2M products.

Reliable Production and Supply

High Quality CO2 Sensors

Made in Japan.
All CO2 sensors are factory calibrated to standard CO2 gas in a computer-controlled automatic calibration system. Stringent quality control processes at Figaro ensure high reliability of its gas sensors.

For VOC, CO, CO2 A single source for air quality control
gas sensor requirements

Figaro has a wide range of product lines, including semiconductor VOC sensors for detection of low concentrations and battery operable electrochemical CO sensors. Figaro is one of the few gas sensor manufacturers in the world supplying VOC, CO, and CO2 gas sensors.

MOS type Electrochemical type NDIR type

Click the model number for more details.


Click the model number for more details.


Click the model number for more details.

FIGARO Engineering inc
Learn more about FIGARO
Contact Us