Activity: Talk or presentation › Invited talk › Science to science
Ambient air is a complex mixture of chemicals with poorly understood interactions and feedbacks. Car exhaust, secondhand smoke, factory emissions, cosmetics, glues, paints, etc. constitute the air we breathe and yes, every breath we take is an airborne chemical cocktail. After having been processed by our body, exhaled air contains numerous markers about the state of our health. Fruity odors in the breath, for example, relate to diabetics; foul ones to respiratory tract infections. Also in daily lives, we use smell to test the freshness and quality of food and beverages. For more than 30 years engineers have been working on an affordable technology to read and understand the composition of ambient air in place. Over the past years, low-cost solid-state gas sensors became available on the market. However, they not only drift over time but also suffer from cross-sensitivities and dependency on environmental conditions. In this talk, I will summarize the state of the technology, and discuss my recent research results and experience in the field. I will present solutions to the following major challenges of building networked sensing systems based on low-cost gas sensors: (1) low signal selectivity and how to improve it by constructing coherent sensor arrays, and (2) poor signal stability and inherent regular sensor re-calibration, possibly over multiple hops.