Semiconductor Sensor Virtual Array: Gas Detection Strategy in Internet of Things to Suppress Humidity Interference

Semiconductor sensors are widely used in gas monitoring of living and industrial environment in the Internet of Things, but humidity interference affects the detection accuracy. The virtual array is proposed as a novel measurement method. It has the advantages of humidity suppression, low-power consumption, and simple structure, which is conducive to further research and development of intelligent sensing device with integrated sensing, memory, and computing in the Internet of Things. This method adopts the heating mode of cyclic variable temperature and extracts the stable conductance values at different temperatures as the response. In the design of a virtual array, the response difference between reducing gas and humidity at different temperatures is used to overcome humidity interference. The output information is expanded from the perspective of measurement so that the humidity interference quantity is characterized simultaneously. Cyclic variable heating voltage is applied to the sensor to obtain the response value under different heating conditions. The response values under high and low levels are displayed as coordinates in the 2-D plane. Samples with reducing gas and humidity are satisfied by the law of the approximate vector sum of their one-component responses. This method was not only confirmed in the main experiment of toluene detection but also in the detection of butanone and the detection of toluene by multiple sensors.