Infineon Technologies is using its MEMS-based CO 2 sensor to measure aerosols in the air.
The company is installing its XENSIV PAS CO 2 sensor in 200 conference rooms across its headquarters in Munich using engineering samples to measure the air quality, says Reinhard Ploss, CEO of Infineon. “The CO2 correlates with aerosols and triggers an alarm,” he said. “The CO 2 level is visualised in real time and this is ideal for closed spaces and in the coming weeks we will be installing the system in 200 meeting rooms at our headquarters. It could also provide simple monitoring in schools and public areas to prevent local infections.”
The sensor has started production ramp for customers. “We are in the process of ramping up this sensor for our conference rooms using engineering precursor product sand we are surprised to see how quickly this is being used,” he said. “What is measured is a CO 2 molecule that is illuminated with an infrared beam at a certain frequency which moves in a characteristic way, then stops with a ‘click’ that you can measure with a microphone – it’s much more precise than other sensors,” he said.
The sensor uses photoacoustic spectroscopy (PAS) with the XENSIV IM69D130 MEMS microphone as a detector. The single PCB (above) combines the photoacoustic transducer with the detector, the infrared source and the optical filter. It also holds a microcontroller for signal processing and algorithms as well as a MOSFET to drive an infrared source.
The integrated microcontroller converts the MEMS microphone output into a ppm reading, which is available either via the serial I²C, UART or PWM interface and covers a range from 0 ppm to 10,000 ppm with an accuracy of ± 30 ppm or ±3 percent of the reading. In a pulsed mode, the PAS is designed to have a lifetime of ten years and reduces space by 75 percent in customer end products compared to commercially