A Portable Odor-Tracing Instrument

In this paper, we present the design of a portable odor-tracing instrument and propose a new method for odor tracing using the instrument. The odor-tracing instrument comprises three gas sensors, a microprocessor, and a liquid crystal display. The gas sensors are placed in a regular triangle. When odor molecules reach the surface of a gas sensor, the output of the sensor changes. To obtain more features from the sensor outputs, we use a scale-space method to obtain multitime-scale information. A time series for the sensor data can then be calculated by feature-point matching. The direction of the odor source can be estimated using a graphical statistical method. The method uses relative output information from the sensors to eliminate the influence of sensor drift. Indoor and outdoor experiments showed that the instrument could indicate the odor source precisely in a windy environment. According to the guidance of the system, users can locate an odor source precisely.