Exhaled Breath Ethanol Detection System Based on In₂O₃/Au-Nanorods Using STM32

The In₂O₃/Au-nanorods (NRs) ethanol sensor with a simple peripheral driver circuit has been fabricated, which has highly sensitive to ethanol biomarkers in breath. This paper firstly describes fabrication method of In₂O₃/Au-NRs and its gas-sensing characteristics under laboratory conditions, then the STM32 sensor detection system and the application of the sensor in the system in detail. The In₂O₃/Au-NRs sensor exhibits strong humidity interference resistance and can detect different concentrations of ethanol gas accurately. The main controller STM32 is applied to the ethanol sensor data acquisition system to reduce the development cost and speed up the development cycles. A 4.3-inch capacitive touchscreen with integrated functionality modules including detection, alarm, touch input, and software reset has been designed, which has extensive versatility for ethanol detection scenarios. First, the principle and process of touch buttons, system block diagrams, hardware circuit schematics, and program flowcharts were designed. Then, the program development was streamlined and made more efficient with the help of STM32cubeMx and HAL libraries, simplifying the initialization and configuration procedures. The rendered images demonstrate that the ethanol detection system designed with In₂O₃/Au-NRs based on STM32 exhibits good detection accuracy and excellent portability.