Multifunction Sensor And Its Application Systems Development

Multifunctional combined sensor is a developing trend of sensitive technology as it has many advantages, such as multifunction, compact structure, and high performance/price ratio. With the rapid progress of science and technology, information from single sensor will no longer meet actual demand, and it is requisite to employ multifunctional sensor to detect environmental variation.According to the analysis and characterization of temperature sensor, humidity sensor and oxygen sensor, a converting circuit for multifunctional combined sensor was designed. Using this circuit the output from each sensor can be converted into a unified voltage which is proportional to the change of measuring parameter. The sensitivity of the multifunctional combined sensors was also verified and analyzed.Based on the multifunctional combined sensors, application system was succeeded, which consists of multifunctional sensor data acquisition, single chip computer, data display, and controller area network (CAN)-bus protocol node unit. The data from multifunctional combined sensors was processed through 12 bits A/D conversion by microcontroller AT89S52 and displayed in real-time by liquid crystal display (LCD). Simultaneously, the obtained data was transmitted on CAN protocol. In CAN network, the information in all of the nodes could be exchanged mutually, i.e., multi-host transmitting mode was realized in CAN network.In order to reduce the volume of the hardware of the application system and enhance the stability and reliability during operation, every aspects, such as circuit design, device type, and PCB design were taken into consideration. For instance,"watchdog"to monitor the system and digital filter in software were utilized. The software programmed by C language composing of a modular structure is beneficial for reducing the volume of software as well as improving code efficiency and operational reliability.The multifunctional combined sensors and their application system studied in this work will play a crucial role in the field of environment, aerospace, medicine, food and...