Arne Grävemeyer

c't 2021, issue 20, page 114-117

With electronic odor sensors, smartphones could soon distinguish fresh milk from sour milk or recognize meadow flowers. In the lab, adaptive e-noses are already sniffing. Smells are everywhere and reveal a great deal about the things around us, for example about herbs, the degree of ripeness of fruits or that of cheese. Smells warn us about toxic solvents or a room fire. But so far, it has been difficult to digitize odors. Analyses in mass spectrometers, for example, are time-consuming and expensive and initially only determine chemical components. Their meaning then still has to be interpreted separately. A team led by Professor Christof Wöll at the Institute for Functional Interfaces at the Karlsruhe Institute of Technology (KIT) is taking a comparatively simple and direct approach in the laboratory. It has developed so-called quartz microbalances as odor sensors. These consist of quartz resonators, which are available today as an electronic mass product for a few cents and ensure, for example, the exact compliance of transmitting and receiving frequencies in smartphones. These components react very sensitively to changes in weight on their surface.

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