Miniature gas sensor lets smartphones measure air quality, wellness
The miniaturised gas sensor is based on Fabry-Pérot interferometers (FPI) — adjustable optical filters. Over the years, VTT has developed these for various spectroscopy-based applications, such as hyperspectral cameras for nanosatellite- and drone-based environmental monitoring, the early detection of skin cancer and fuel analysis for emission minimization.
Many sensor developers are interested in using smartphones to measure gas concentrations.
"This is probably due to the spread of the Internet of Things (IoT), which enables indirect observations of a range of environmental factors based on data gathered from single sensors or sensor networks. Many day-to-day issues, such as precision and efficiency in the workplace, can depend on carbon dioxide levels and internal air quality," says Anna Rissanen, leader of the VTT research team.
Using a mobile device to measure carbon dioxide will also enable new applications for smartphones: for example, sleep quality can be monitored by measuring the sleeper’s exhalations.
VTT has developed a gas sensor that can be connected to mobile devices. Using a mobile device to measure carbon dioxide creates the possibility of developing new kinds of mobile phone applications. For example, sleep quality can be monitored by checking the levels of carbon dioxide exhaled by the sleeper.
The tiny gas sensor developed by team’s senior scientist Rami Mannila is based on channeling light through the sample being analyzed. Penetrability at various light wavelengths can be used to determine the composition of the compound. Carbon dioxide is identified based on its strong absorption of light at a wavelength of 4.2 µm. In addition, a corresponding sensor technology can be used to simultaneously differentiate and detect other gases or substances based on the spectrum of their absorption peaks at various infra-red wavelengths.
VTT Technical Research Centre of Finland: www.vttresearch.com
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