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enriquezgarc edited this page Jul 6, 2021 · 2 revisions

Welcome to the PAS CO2 C++ library docs!

This software enables the usage of Infineon's PAS CO2 XENSIV™ in embedded systems and applications. You can find all the related information in this wiki.

PAS CO2 Sensor

The XENSIV™ PAS CO2 integrates on the PCB the photoacoustic (PAS) transducer, including a detector, infrared source and optical filter; a microcontroller for signal processing and algorithms; and a MOSFET chip to drive the infrared source. The integrated microcontroller runs ppm calculations as well as advanced compensation and configuration algorithms.

The sensor uses a MEMS acoustic detector. The exceptional sensitivity of this acoustic detector coupled with the integrated PCB design reduces space requirements by more than 75 percent compared to other commercially available CO2 sensors. Therefore, the XENSIV™ PAS CO2 sensor outperforms state-of-the-art NDIR sensors in terms of size and cost, without compromising on performance.

Photoacoustic Principle

The PAS principle works as follows. Pulses of light from an infrared source pass through an optical filter tuned specifically to the CO2 absorption wavelength (λ= 4.2 µm). The CO2 molecules inside the measurement chamber absorb the filtered light, causing the molecules to shake and generate a pressure wave with each pulse. This is called the photoacoustic effect. The highly sensitive MEMS acoustic detector detects the pressure change generated by CO2 molecules within the sensor cavity, and the microcontroller converts the output into a CO2 concentration reading. In order to achieve a ppm reading as accurate as possible, the acoustic detector is optimized for low frequency operation, and the absorption chamber is acoustically isolated from external noise.

For more information about the sensor visit the Infineon product site.

C++ Library Features

  • Complete sensor operation modes support
  • MCU software control support for all sensor GPIO interfaces
  • I2C, UART, and PWM interfaces
  • Platform Abstracted Architecture
  • Supported software frameworks
    • Arduino

Wiki Sections

1. Home
2. Library Details Library architecture, general API and usage information
3. Hardware Platforms List of supported sensors and microcontroller platforms
4. Software Frameworks List of supported embedded software frameworks and specific APIs
5. Related Links Useful links related to this repository