Fast Transient Classification With a Parallelized Temperature Modulated e- nose In Natural Uncontrolled Environments

In this article we introduce a novel operating principle for a temperature modulated electronic nose. The aim is to perform gas discrimination with metal oxide gas sensors in natural, uncontrolled environments where the sensor is exposed to patches of gas only for short periods of time. The proposed Parallelized Temperature Modulated e-nose (PTM e-nose) allows to speed-up discrimination of gases by measuring in parallel the response of N gas sensors of the same type but with a phase-shifted temperature modulation cycle. The basic idea is to replicate the base sensor N times with each sensor instance measuring one different Nth of the modulation cycle. In this way the response to the full modulation cycle for one sensor can be recovered from N different sensors in one Nth of the time while the chemical response of the individual sensors is not compromised by a too fast temperature change. We demonstrate the proposed operating principle with a PTM e-nose that consists of four commercially available tin oxide gas sensors, which are temperature-modulated with sinusoids of the same amplitude but phase-shifted by 90 degrees. We particularly address gas discrimination in the early stages of the transient response and demonstrate that the information contained in one entire modulation cycle can be sufficiently recovered from the responses of the individual sensors.