A generic multielement microsystem for portable wirelessapplications

An open-architecture microsystem that can be populated with a variety of sensors and actuators is described. The microsystem is designed for low-power wireless applications where small size and high sensor accuracy are important. It consists of an in-module microcontroller connected to multiple front-end transducers through an intramodule sensor bus. An external interface allows internally processed data to be output through either a hard-wired input/output port or a radio-frequency transmitter. The present microsystem is configured for environmental monitoring and measured temperature, barometric pressure, relative humidity, and acceleration/vibration. It occupies less than 10 cc, consumes an average of 530 μW from 6 V, and transmits data up to 50 m. System features such as active power management, the intramodule sensor bus, generic bus interface circuitry, and in-module sensor compensation based on bivariate polynomials are discussed     

高分子湿敏器件的耐水性

为了改善湿敏器件的耐水性能 ,在制备高分子湿敏器件过程中 ,以丙烯酰胺为交联剂并加乙基纤维素保护膜。结果使湿敏器件的耐水性增强 ,但同时也使器件阻值增高 ,湿滞增大 ,吸脱附时间增长。器件再经适当浸水老化后 ,湿滞减小 ,耐水性亦得到进一步改善。     

Recent advancements in flexible humidity sensors

Flexible electronics are attracting widespread attention due to their potential applications in wearable health monitoring and care systems[1],holding great promise in the internet of things(IoT),a fundamental concept in which devices and objects can be interconnected to form extensive networks[2].Especially,the rapid developments of various flexible humidity sensors have broadened the scope of flexible electronics for novel applications in the IoT,such as noncontact and realtime sensation,electronic skin(e-skin),telemedicine monitoring,and wearable electronic systems(Fig.1)[2–4].     

基于LabVIEW的湿敏元件性能测试分析系统

为了克服传统的传感器特性测试仪功能单一、专用性强的缺点,利用GPIB卡组建由ZL5型智能LCR测试仪与计算机构成的湿敏元件性能测试系统,并基于LabVIEW开发出系统控制软件。根据存储文件方式的不同,采用不同的图形分析方法。通过将其应用于氧化钛基薄膜的湿敏特性研究实验,结果表明该系统能够方便、直观地分析湿敏元件的性能。     

MOS structures with amorphous tungsten trioxide for capacitive humidity sensors

Electrical characteristics of the Al/a-WO₃/n-Si structure under conditions of water vapor sorption were studied. The parameters of this structure as a capacitive humidity sensor were determined.     

温湿度传感器的原理及应用

介绍了温湿度传感器DHT90的主要特点、工作原理、典型应用实例及应用程序。     

温湿度传感器的原理及应用

介绍了温湿度传感器DHT90的主要特点、工作原理、典型应用实例及应用程序。     

Uncalibrated automatic bridge-based CMOS integrated interfaces for wide-range resistive sensors portable applications

In this work the authors describe improved solutions on automatic fully-analog uncalibrated Wheatstone bridge-based interfaces suitable for wide-range resistive sensors. The proposed topologies are enhanced and integrated interfaces, based on automatic bridge configurations, completely designed in a standard CMOS technology (AMS 0.35 μm), where Voltage Controlled Resistors (VCRs), formed by MOS transistors, have been properly tuned through the use of a suitable closed feedback loop that continuously ensures the bridge equilibrium condition. The microelectronic design has been performed through the use of symmetrical Operational Transconductance Amplifiers (OTAs) with low-voltage (2 V, single supply) and low-power (63.5 μW) characteristics, so the overall system can be fabricated in a single chip suitable for portable applications. Referring to the first configuration where only one VCR has been employed for both grounded and floating resistive sensors, Orcad PSpice simulations have confirmed the interface capability to estimate the sensor resistance for about 2.7 decades variations (430 Ω; 220 kΩ), with a relative error of about ±4%. Moreover, in the second version for an extended estimation range, the interface is able to evaluate the sensor resistance for about 6.6 decades (0.1 Ω; 400 kΩ) with a reduced relative error within (−1.5%; +4%).     

Characterization of vanadyl phthalocyanine based surface-type capacitive humidity sensors

This study presents the fabrication and characterization of novel surface-type capacitive humidity sensors using vanadyl phthalocyanine (VOPc) as the active material. The devices, which comprise three different thicknesses,have been fabricated using the thermal evaporation technique. A thin film of VOPc is deposited on thoroughly cleaned glass substrates with pre-pattemed Ag electrodes. The capacitive effect of the samples under humidity has been in-vestigated. Comparison of the samples with different thicknesses shows that the thinnest device seems more sensitive towards humidity. The humidity dependent capacitance properties of the sensor make it beneficial for use in commercial hygrometers.     

Characterization of vanadyl phthalocyanine based surface-type capacitive humidity sensors

This study presents the fabrication and characterization of a novel surface-type capacitive humidity sensors using Vanadyl Phthalocyanine (VOPc) as an active material. The devices comprising three different thicknesses have been fabricated using thermal evaporator. Thin film of VOPc is deposited on thoroughly cleaned glass substrates with pre-patterned Ag electrodes. The capacitive effect of the samples under humidity has been investigated. Comparison of the samples with different thicknesses reveals the fact that the device with lesser thickness seems more sensitive towards humidity. The humidity dependent capacitance properties of the sensor make it beneficial for use in commercial hygrometers.     

Fiber-optic sensors for continuous clinical monitoring

Optical sensors are prepared by attaching an indicating layer to the distal tip of an optical fiber. Light is sent down the optical fiber and is modulated by the indicating layer. The degree of modulation of the returned light is a direct measure of the amount of a particular chemical species in contact with the fiber tip. A variety of sensor designs can be employed along with a diverse array of supporting instrumentation. An overview of the various optical transduction mechanisms, instrumentation, and problems associated with optical sensors for continuous clinical monitoring is presented     

湿敏元件在恶劣环境下的失效机理分析

介绍了电容式高分子湿敏元件的基本结构及制造工艺.分析了湿敏元件在恶劣环境下的失效机理及产生的原因,指出了感湿膜中的颗粒状缺陷是造成湿敏元件在恶劣环境下失效的主要原因.提出了在湿敏元件制作、上电极工艺制造技术和湿敏元件筛选检验的改进措施.     

The Design of Interdigitated Couplers for MIC Applications

A straightforward design procedure for microstripline interdigitated directional couplers is outlined. Based on exact, closed-form equations for coupler analysis, a design chart is developed allowing the geometry of the cross section to be found, starting from a prescribed coupling and given bounds on directivity and VSWR. A further chart yields the length of the coupled section once the center-band frequency has been fixed. In this way, a complete picture of coupler performance is made available to the designer so that the necessary tradeoffs between coupling, directivity, and impedance match can be predicted and understood. The accuracy of the design procedure is also discussed in relation with the most important parasitic affecting coupler behavior, such as launching-discontinuity effects and bonding-wire reactances.     

Wireless magnetoresistive microsystem for magnetic field measurements

The design and technology of magnetic semiconductor elements of wireless magnetoresistive microsystems for magnetic field measurements are proposed and the results of the investigations of a highly sensitivity magnetoresistive converter with magnetic field concentrators are presented. The characteristics of the developed measuring amplifier for operation with a signal from a low-resistance magnetoresistive bridge with a certain unbalance value are reported. The technology for fabricating magnetic semiconductor ICs based on thin-film magnetoresistive structures is described.     

A multitransducer microsystem for insect monitoring and control

This paper reports the development and in-vivo testing of a compact multitransducer microsystem intended for neuroethology experiments, including studies of gait dynamics in free-running insects. The system incorporates a combination of custom and off-the-shelf components. Its suite of measurement devices comprises leg-mounted strain gauges, electromyogram (EMG) and extracellular electrodes for the central nervous system, and a two-axis accelerometer. For signal conditioning and selection, the microsystem implements off-the-shelf electronics in a custom chip-on-board configuration. The microsystem measures 16 mm x 19 mm, supports 40 components and 56 I/O leads, and is assembled on a four-layer printed-circuit board. The entire system occupies only 0.65 cm3 and weighs less than 5 g. It has been successfully used to monitor leg-strain and EMG signals on walking cockroaches and for stimulation in the insect central nervous and muscular systems.     

应用于微系统封装的激光局部加热键合技术

阐述了利用激光与物质相互作用的热效应实现微系统器件的局部加热键合原理 ,提出了激光键合塑料芯片和激光辅助加热阳极键合的思想 ,建立了半导体激光键合实验装置 ,并实现了聚甲基丙烯酸甲酯 (PMMA)之间的键合     

应用于微系统封装的激光局部加热键合技术

阐述了利用激光与物质相互作用的热效应实现微系统器件的局部加热键合原理，提出了激光键合塑料芯片和激光辅助加热阳极键合的思想，建立了半导体激光键合实验装置，并实现了聚甲基丙烯酸甲酯(PMMA)之间的键合。     

Capacitive humidity sensors based on MWCNTs/polyelectrolyte interfaces deposited on flexible substrates

Inexpensive humidity sensors operating at room temperature are developed by casting on glossy paper linearly shaped carbon nanotubes electrodes, spaced by few hundreds microns, and sensitive layers consisting of iron oxide nanopowder dispersed in a polyelectrolyte host. The electrical behaviour of the devices, investigated by using triangular voltage inputs, is found to be mainly capacitive. The humidity sensing functionality is demonstrated by a reversible change of the devices’ capacitance, from few tens pF to hundreds pF, as the relative humidity level changes from 35% to 60%. The average response and recovery time of the devices is found to be of the order of a few min.     

A programmable microsystem using system-on-chip for real-time biotelemetry

A telemetry microsystem, including multiple sensors, integrated instrumentation and a wireless interface has been implemented. We have employed a methodology akin to that for System-on-Chip microelectronics to design an integrated circuit instrument containing several "intellectual property" blocks that will enable convenient reuse of modules in future projects. The present system was optimized for low-power and included mixed-signal sensor circuits, a programmable digital system, a feedback clock control loop and RF circuits integrated on a 5 mm x 5 mm silicon chip using a 0.6 microm, 3.3 V CMOS process. Undesirable signal coupling between circuit components has been investigated and current injection into sensitive instrumentation nodes was minimized by careful floor-planning. The chip, the sensors, a magnetic induction-based transmitter and two silver oxide cells were packaged into a 36 mm x 12 mm capsule format. A base station was built in order to retrieve the data from the microsystem in real-time. The base station was designed to be adaptive and timing tolerant since the microsystem design was simplified to reduce power consumption and size. The telemetry system was found to have a packet error rate of 10(-3) using an asynchronous simplex link. Trials in animal carcasses were carried out to show that the transmitter was as effective as a conventional RF device whilst consuming less power.