Infineon's XENSIV PAS CO2 CO2 sensor. Based on the principle of photoacoustic spectroscopy (PAS), the product uses a highly sensitive MEMS microphone to detect pressure changes generated by CO2 molecules in the sensor cavity. This method of detection can significantly reduce the size of the CO2 sensor and save more than 75% of space in the final product compared to other CO2 sensors on the market.

     The Infineon XENSIV PAS CO2 sensor integrates a photoacoustic sensor containing a detector, infrared source and optical filter, a microcontroller for signal processing and algorithms, and a MOSFET for driving the infrared source. Where the integrated microcontroller converts the output of the MEMS microphone into ppm readings and provides these readings through serial I²C, UART, or PWM interfaces. The sensor has measurements ranging from 0ppm to 10,000 PPM, with an accuracy of ±30ppm or ±3% of the reading.

     Because the sensor provides direct-readable ppm readings, allows surface mount, and is simple in design, it can be quickly integrated into a variety of low - and high-volume applications, such as smart home and building automation designs, on-demand ventilation systems, air purifiers, thermostats, weather stations, and personal assistants.