An integrated sensor system is implemented using inter-integrated circuit mode (I2C) software, utilizing the PIC182585 MPLAB embedded control system utilizing hardware. The hardware implementation features high level ...An integrated sensor system is implemented using inter-integrated circuit mode (I2C) software, utilizing the PIC182585 MPLAB embedded control system utilizing hardware. The hardware implementation features high level of integration, reliability, high precision, and high speed communications. The system was demonstrated by temperature and CO2 sensors. An extension for Zigbee system is proposed to enhance the security of the integrated system. A bi-directional air/liquid flow sensor is also added to detect the flow magnitude and direction that can be applied to heating, ventilating, and air-conditioning (HVAC), local and national security within subway systems, and medical equipment. The hardware design of the flow sensor included one heating element and two sensing elements to detect the bi-directional flow. Platinum sensors were found to be of high sensitivity and linear characteristics within 0℃ to 100℃ range, and their high temperature coefficient (0.00385 Ω/Ω/℃). Polyimide thin film heater was used as the heating element due to its high throughput and good thermal efficiency. Two bridge circuits were also designed to sense the temperature distribution in the vicinity of the sensing elements. Three high precision instrumentation low power amplifiers with offset voltage ~2.5 μV (50 μV max) were used for the overall design. The system security is also enhanced with the detection of poison gas using Carbon Nanotube devices (CNT). An antenna system was designed, and a frequency shift was detected to designate the type of poison gas used for a general threat.展开更多
In this work we have designed and simulated a thermal bi-directional integrated circuit mass flow sensor. The approach used here was an extension to the gas flow model given by Mayer and Lechner [1]. The design featur...In this work we have designed and simulated a thermal bi-directional integrated circuit mass flow sensor. The approach used here was an extension to the gas flow model given by Mayer and Lechner [1]. The design features high precision response received from analog integrated circuits. An established mathematical model for the heat flow equation including CFD parameters were used within COMSOL simulation (COMSOL Multiphysics, Sweden). Heat pulses of 55°C for a period of nearly 120 seconds and 50% duty cycles were applied as thermal sources to the flowstream. The boundary conditions of the heat equations at the solid (heating element) fluid interface were set up in the software for the thermal response. The hardware design included one heating element and two sensing elements were used to detect the bi-directional mass flow. Platinum sensors were used due to their linear characteristics within 0°C to 100°C range, and their high temperature coefficient (0.00385 Ω/°C). Polyimide thin film heater was used as the element due to its high throughput and good thermal efficiency. Two bridge circuits were used to sense the temperature distribution in the vicinity of the sensing elements.展开更多
文摘An integrated sensor system is implemented using inter-integrated circuit mode (I2C) software, utilizing the PIC182585 MPLAB embedded control system utilizing hardware. The hardware implementation features high level of integration, reliability, high precision, and high speed communications. The system was demonstrated by temperature and CO2 sensors. An extension for Zigbee system is proposed to enhance the security of the integrated system. A bi-directional air/liquid flow sensor is also added to detect the flow magnitude and direction that can be applied to heating, ventilating, and air-conditioning (HVAC), local and national security within subway systems, and medical equipment. The hardware design of the flow sensor included one heating element and two sensing elements to detect the bi-directional flow. Platinum sensors were found to be of high sensitivity and linear characteristics within 0℃ to 100℃ range, and their high temperature coefficient (0.00385 Ω/Ω/℃). Polyimide thin film heater was used as the heating element due to its high throughput and good thermal efficiency. Two bridge circuits were also designed to sense the temperature distribution in the vicinity of the sensing elements. Three high precision instrumentation low power amplifiers with offset voltage ~2.5 μV (50 μV max) were used for the overall design. The system security is also enhanced with the detection of poison gas using Carbon Nanotube devices (CNT). An antenna system was designed, and a frequency shift was detected to designate the type of poison gas used for a general threat.
文摘In this work we have designed and simulated a thermal bi-directional integrated circuit mass flow sensor. The approach used here was an extension to the gas flow model given by Mayer and Lechner [1]. The design features high precision response received from analog integrated circuits. An established mathematical model for the heat flow equation including CFD parameters were used within COMSOL simulation (COMSOL Multiphysics, Sweden). Heat pulses of 55°C for a period of nearly 120 seconds and 50% duty cycles were applied as thermal sources to the flowstream. The boundary conditions of the heat equations at the solid (heating element) fluid interface were set up in the software for the thermal response. The hardware design included one heating element and two sensing elements were used to detect the bi-directional mass flow. Platinum sensors were used due to their linear characteristics within 0°C to 100°C range, and their high temperature coefficient (0.00385 Ω/°C). Polyimide thin film heater was used as the element due to its high throughput and good thermal efficiency. Two bridge circuits were used to sense the temperature distribution in the vicinity of the sensing elements.
