呼吸率传感器的智能化设计

本文针对生理参数-呼吸率的检测问题,具体阐述了智能化呼吸率检测系统的硬件组成,工作原理以及软件分析.     

温度不敏感的柔性氧化石墨烯湿度传感器研究

本文设计并制作了一种氧化石墨烯(GO)柔性湿度传感器,通过阻抗分析测试法,分别比较了温度对其电阻和电容湿敏特性的影响,并研究了其动态响应特性。结果表明,电阻工作模式的GO柔性湿度传感器湿敏特性受温度影响较大,而电容工作模式则几乎对温度不敏感。当湿度为50%时,传感器的响应时间和恢复时间分别约为1.7s和8.4s。同时,验证了该传感器可实现穿戴式人体呼吸频率的监测。     

多传感器数据融合技木在汽轮机排汽湿度监测系统中的应用

在湿度监测系统中,由于各温度、压力传感器所处的方位不同以及受传感器自身在实际环境中一些无法控制的随机因素影响,使得测量数据不能完全反映汽轮机排汽湿度的真实状态。对此,需要汽轮机排汽湿度监测系统通过数据     

基于单片机的蜂箱蜜蜂监测系统设计

针对蜜蜂养殖业及科学研究中存在的蜂箱内蜜蜂数量监测困难的问题,提出一种用于监测蜂箱中蜜蜂数量的监测系统。系统采用STC89C52单片机作为控制核心,用光电传感器H42B6感应外界光线的变化,通过触发单片机的外部中断识别蜜蜂的经过,根据触发顺序判断蜜蜂的进出方向,通过单片机进行数据处理,并将处理后的数据送入串口,最终通过串口调试工具显示在上位机界面上。实验结果证明:该系统能精确地统计出蜂箱中蜜蜂的进出数目,给养蜂者的管理提供准确依据。     

基于多孔氧化铝湿度传感器的土壤湿度监测系统

针对对土壤湿度的自动监测,以微型处理器为核心控制单元,设计了温度检测、测量放大电路、控制电路、显示电路、执行电路等;通过参考元件的选用及测量电路的优化来改善土壤环境对测量精度的影响,以实现高效地、便捷地土壤湿度监测系统。     

湿度传感器响应时间校准规范的制订

湿度传感器响应时间在不同的环境温度、环境风速下,其测量结果会有很大的差别,特别是环境温度对湿度传感器响应时间的影响更大,在-20℃条件下与+50℃条件下其响应时间相差达四倍多。因此,有必要制订用于统一湿度传感器响应时间校准的技术标准,并对湿度传感器响应时间校准时的测量环境条件与校准方法做出规定。     

湿度传感器在防护性能检测中实现动态湿度测量的探讨

防护器材的防护性能受湿度的影响很大,用干、湿球温度计来测量湿度的方法早已无法满足现代科技发展的需要.笔者对湿度传感器在防护性能检测中实现动态湿度测量进行了探讨,并结合实际工作经验,从湿度传感器的特点、性能、主要参数以及如何选型,介绍了自己的体会.     

基于LabVIEW的湿度传感器自动测试系统设计

本文介绍了湿度传感器自动测试系统的组成和工作原理,以及利用LabVIEW图形化编程语言设计实现的自动测试系统软件的方法和思路,重点阐述了状态机程序设计思想以及串口信号采集、数据存储、报表生成等编程技术.本文设计的自动测试系统实现了湿度传感器自动数据采集、存储、报表生成等基本功能,具有操作方便、易于二次开发等特点.     

测量介质湿度的频域传感器的研究

介绍了一种新型的测量介质湿度的频域传感器。利用介质的介电常数随介质湿度的变化关系,通过测量传感器极间的电容和电阻,来实时测量介质湿度及离子电导率;研制了传感器的实验装置;研究了介质的介电常数随温度,介质中盐分等的变化关系。通过实验所得的实际值进行了温度和离子电导率等的补偿。     

Study of a fiber optic humidity sensor based on agarose gel

An optical fiber humidity sensor was fabricated using a hydrophilic gel (agarose) deposited on the tapered plastic optical fiber (POF). The sensing element, agarose, can absorb and exude moisture from/to the ambience, thereby altering its refractive index and changing its ability to modulate the intensity of light that propagates through the fiber. Thus, the operating principle of the sensor is based on the intensity modulation technique, which utilizes a tapered POF probe coated with agarose that is sensitive to humidity. The POF, which was fabricated using an etching method, has a waist diameter of 0.45 mm and tapering length of 10 mm. As the relative humidity varies from 50% to 80%, the output voltage of the sensor with agarose gel of 0.5% weight content decreases linearly from 2.24 mV to 1.55 mV. The agarose-based sensor produces a sensitivity of 0.0228 mV/%, with a slope linearity of more than 98.36%. The tapered fiber with agarose gel of 1% weight content produces a sensitivity of 0.0103 mV/% with a slope linearity of more than 94.95% and a limit of detection of 2.635%, while the tapered fiber with agarose gel of 1.5% weight content produces a sensitivity of 0.0079 mV/% with a slope linearity of more than 98.53% and a limit of detection of 6.853%. The fiber with agarose gel of 0.5% weight content shows higher sensitivity compared to that of 1% and 1.5% due to the effect of pore size, which changes with concentration. The results demonstrate that agarose-based optical fiber sensors are both sensitive and efficient for economical and flexible measurements of humidity.     

基于无线传感器网络的社区保健监测系统

以躯域传感网络技术为载体,结合无线传感器网络在社区的合理安置,研究人体生理参数的无创连续监测技术以及穿戴式医疗仪器开发,设计了一个适用于慢性病人(如糖尿病人)的社区无线医疗保健监测网络系统;同时设计出一种新的无线传感器网络低能量数据汇聚模型——集合汇聚模型,把此模型应用于本系统以期达到降低能耗延长网络生命周期目的.最后,提出了在人体生理数据处理过程中需考虑的数据分级处理和安全问题.     

Photocatalytic ozone sensor based on mesoporous indium oxide: Influence of the relative humidity on the sensing performance

Mesoporous In₂O₃, synthesized by a nanocasting procedure, is used as a resistive gas sensor for ozone in very low concentrations (from 20 ppb to 2.4 ppm) at room temperature. Its sensing performance is substantially increased by illumination with blue light (460 nm, 2.7 eV). For low ozone concentrations the sensor response increases with increasing humidity. However, higher humidity also results in the occurrence of a saturation of the response at lower ozone concentrations; this is rationalized by assuming a poisoning of surface active sites by hydroxyl groups.     

Experimental investigations on barium titanate nanocomposite thin films as an opto-electronic humidity sensor

This article reports the synthesis and characterisation of Barium titanate (BaTiO₃) nanocomposite and its application as opto-electronic humidity sensor. Titanium tetrachloride and barium hydroxide were mixed in molar ratio 1?:?1 in deionised water under continuous stirring at room temperature. Later, sodium hydroxide solution was added to above solution with continuous stirring. Finally, BaTiO₃ gel was obtained. The synthesised nano-composite material was characterised using a scanning electron microscope, X-ray diffraction (XRD) and UV-Visible spectrophotometer. SEM image of the composite film shows that the film is porous having uniform grains. From XRD the minimum crystallite size of BaTiO₃ was found to be 8?nm using Debye–Scherer formula. UV-Visible absorption spectroscopy was used for optical characterisation of the film. It was found that the optical band gap of the composite material was 3.50?eV. Barium titanate thin film was deposited on the base of an equilateral prism using sol–gel spin coating process at 4000?rpm. The humidity sensing properties of the film was investigated at different angles of incidence. It was observed that the intensity of reflected light increased with an increase in relative humidity (%RH) in the range 5–95% at a particular angle of incidence. Sensing element has maximum sensitivity ～6?µW/%RH, which is quite significant for sensor fabrication purposes.     

ZigBee技术的汽车胎压监测系统设计

针对目前直接主动式汽车胎压监测系统处理器与射频芯片分开设计、433 MHz无线频率造成的系统体积大、无组网、抗干扰能力弱等关键技术问题,设计了一种基于无线传感器网络的直接主动式汽车胎压监测系统.其中系统采用ZigBee首款SOC单芯片CC2430,无线通信频率为2.4 GHz.软件设计上改进了ZigBee通讯协议CSMA/CA机制,这样既能有效避免各轮胎监测节点发送数据的冲突,又能降低系统能耗、延长网络寿命.该系统能够实时自动监测轮胎内部压力、温度等状态信息,从而有效地保障了汽车行驶安全.     

MEMS传感器输电线路舞动轨迹监测

中国部分地区输电线路舞动事故频繁发生,为提供舞动预警及理论分析数据,提出一种基于MEMS六轴惯性传感器的输电线路舞动轨迹监测算法.算法给出舞动轨迹监测一般解算流程,以MEMS六轴惯性传感器敏感输电线路舞动的角速度、加速度信息可有效解决仅用三轴加速度计所存在的线路空间扭转问题,为有效抑制MEMS传感器中陀螺仪误差随时间累...     

基于ZigBee无线传感网的泥石流多发地数据采集系统

针对有线传感网数据采集系统布线成本高以及无法在环境恶劣的野外放置等问题,介绍一种基于ZigBee无线传感网的数据采集系统。该系统由基于MSP430单片机的主机、子机组成,子机由太阳能供电连接传感器,放置在户外采集数据,主机连接PC机放置在室内,主机和子机通过ZigBee无线网络通信。该系统实现了野外数据的采集和无线传输,具有实时性、稳定性等特点,可用于地质分析和泥石流预警等系统,以及各种无线传感网数据采集系统。     

泰州大桥结构健康监测系统设计

依托泰州大桥工程概略论述了特大悬索桥梁结构的健康监测系统设计。泰州大桥结构健康监测系统由传感器子系统、数据采集与传输子系统、数据处理与控制子系统3个子系统构成。其中,泰州大桥数据采集与传输系统将传统的有线采集模式和新型的无线采集模式进行了融合,是国内外首次大规模应用。     

恒温恒湿空调系统设计中的几点体会

结合近年来典型工程实践,对高精度恒温恒湿空调系统设计中的一些问题进行分析,总结恒温恒湿空调系统设计中必要的技术措施和体会,以供设计参考。