Thick films of copper-titanate resistive humidity sensor

The humidity-sensitive TiO₂-Cu₂O-Na₂O thick films were prepared by screen printing on alumina substrates and subsequent firing. Pastes for screen printing were obtained by adding an organic vehicle and binder to TiO₂-Cu₂O-Na₂CO₃ powders. The microstructure of the films changed with the content of the sodium oxide and the firing temperatures. When the resistance characteristics of the sensors obtained from TiO₂-Cu₂O-Na₂O, 10-2-1 were measured, the resistance changed linearly in its semi-logarithmic graph. The resistance varied from 10⁷ to 10⁴ Ω between 20 and 95%RH, which was required for a common humidity sensor. Temperature dependence, frequency dependence and response time were also measured and estimated.     

谐振式MEMS磁传感器接口电路设计

介绍了一种谐振式微系统（MEMS）磁传感器的接口电路,电路由驱动电路和信号检测处理电路组成。驱动电路采用直接数字频率合成器（DDS）产生磁传感器驱动信号,同时为检测电路提供同步信号;信号检测处理电路对磁传感器输出信号和 DDS 产生的同步信号进行同步解调,最终得到所需的磁场信号。最后对电路的性能和测试结果进行分析和总结。     

一种宽量程气压传感器的接口电路设计与测试标定

高空探测气压传感器,其特点是测量量程宽,满足常压到极低压(10 hPa)测量,因此,专用型压阻式气压传感器输出信号检测与数模转换接口电路的设计,是推广高空探测气压传感器应用的关键技术之一,具有十分重要的现实意义和广阔的使用前景。本文针对宽量程检测特点设计了压阻式气压传感器专用接口电路,解决了传感器微小电阻变化量的检测问题,并对传感器性能进行测试分析与标定,可实现传感器全量程误差不超过2.6 hPa,并实现数字化输出,完成传感器接口电路设计。     

Ecological interface design and sensor noise

This paper investigates the effects of the presence and magnitude of sensor noise on operators' performance and control stability when they use an Ecological Interface Design (EID) interface and a non-EID interface. Sensor noise was gradually increased in selected low-level physical sensors of DURESS III, a representative thermal-hydraulic process simulation. There are two important findings. First, participants in the EID condition achieved target goals significantly faster across all magnitudes of sensor noise. Second, participants in the EID condition exhibited more stable control; experiencing fewer and shorter oscillations around the target goals. This is the first study to empirically investigate the impact of the presence and magnitude of sensor noise on the robustness and effectiveness of an EID interface. These findings are important if EID is to be applied in industrial settings.     

A CMOS integrated interface circuit for metal-oxide gas sensors

This paper presents an integrated gas-sensor interface circuit that includes a high-efficiency temperature control loop, with a switching power stage and a digital set-point, as well as a wide-dynamic range read-out circuit. The temperature control loop adjusts the temperature of the sensor over a range of 250 °C with an accuracy better than 1.5 °C and with a maximum peak-to-peak ripple of 1.0 °C. The read-out circuit achieves, without calibration, a precision in sensor resistance measurement of 2.65%, over a range of 5.3 decades, leading to an equivalent dynamic range of 138 dB. The overall system is flexible and can be interfaced to sensors with different fabrication parameters. The interface circuit chip, realized with a 0.35 m CMOS technology, includes on the same 10-mm² die the high-accuracy read-out circuit and the switching power stage. In spite of the interferences produced by the power stage, the read-out circuit maintains always a dynamic range performance above 130 dB. The proposed interface circuit, together with a micromachined metal-oxide gas sensor, can detect 3 ppm of CO in air.     

基于无线传感器技术的人机接口系统设计

在综合研究脑电和眼电信号采集理论和方法的基础上,研制出一种基于无线传感器技术的新型多通道人机接口系统,包括无线传感器部分、信号处理和控制电路部分.该系统实时采集受试者垂直眼电和水平眼电,将其数字化,通过短距离无线技术传送给主机,主机信号处理系统根据眼电幅值判断受试者眼球转动方向,由此控制遥控汽车做相应的移动.实验结果表...     

一体化小桥式称重传感器的设计

电子称量系统在各个称量领域的应用极为广泛,而桥式称重传感器是电子称量系统的核心元器件。一体化小桥式称重传感器是将底座与弹性体合为一体来大大缩小传感器的几何形体,并将传感器的自重大幅度降低的一种设计方法。这样更便于电子称量系统的安装和维护,缩短电子称量系统的安装和维护周期。     

磁阻传感器在转速测量中的应用

介绍了一种以磁阻传感器为磁敏元件,以单片机为控制核心的高精度转速测量方法。论述了测量系统工作原理、各硬件部分功能。传感器探头由激励线圈和磁阻传感器构成,输入的电流在激励线圈周围产生交变磁场,当齿轮转动时,激励线圈的磁场发生变化,位于线圈中央的磁阻传感器将其转变成电信号,在单片机的控制下进行放大处理和显示。该转速传感器具有准确度高、测量范围宽、安装调试方便等优点。     

一种基于有源电桥的电容式粮食水分传感器

在传统电桥电路的基础上,设计了一种有源电桥的电容式检测电路。该电路具有灵敏度高、线性范围宽的特点。将其用于粮食水分的检测,实现了一种具有线性特性的粮食水分传感器。通过试验测试粮食的电阻抗特性,尤其是电容特性与粮食水分之间的关系,确定了电路的工作频率。试验结果表明:这种粮食水分传感器的输出电压与粮食水分之间呈良好的线性关系,可满足粮食水分在线检测的要求。     

网络传感器接口设计与验证

以ADuC812微控制器为核心,依据网络智能传感器接口标准IEEE 1451.2,探索了智能传感器接口模块(STIM)的设计思想与实现方法,用PC机编制程序实现网络匹配处理器(NCAP)的功能,在线存储、修改电子数据表单(TEDS),实现传感器/执行器的即插即用。     

磁致伸缩位移传感器的应用

简单介绍磁致伸缩传感器的原理及特点,同时介绍了磁致伸缩传感器在高精度位移检测中的应用实例。     

霍尔式传感器的信号调理电路

根据霍尔传感器的特性和MAX14 5 7的工作原理 ,提出将MAX14 5 7应用于霍尔传感器信号调理的方案。可对传感器进行自动校准 ,实现对多达 12 0个点的热零点漂移、热灵敏度漂移的自动数字化补偿和非线性误差修正 ,大幅度减小测量误差     

Low-cost colorimetric sensor for the quantitative detection of gaseous hydrogen sulfide

A simple, rapid and low-cost method for differentiating a wide range of concentrations of gaseous hydrogen sulfide (H₂S) is described. A large dynamic range (50 ppb to 50 ppm) was successfully classified at ambient temperature using a colorimetric sensor array comprised of chemoresponsive dyes coupled to a commercially available 8-bit flatbed scanner. Principle component analysis of the composite magnitude and kinetics of color change for the array of dye spots over the entire dynamic range resulted in 100% classification. This was achieved by including chemoresponsive dyes which reacted specifically with H₂S at different detection thresholds.     

Nano particulate SnO2 based resistive films as a hydrogen and acetone vapour sensor

SnCl₂ (solution) was spin coated on soda lime glass and Al₂O₃ substrate to obtain nano-particulate tin oxide film, directly by sintering at 550 °C for 40 minutes (min). The surface morphology and crystal structure of the tin oxide films were analyzed using atomic force microscopy (AFM) and X-ray diffraction (XRD). The size of SnO₂ nanostructure was determined from UV-vis and found to be ?3 nm. These films were tested for sensing H₂ concentration of 0.1-1000 ppm at optimized operating temperature of 265 °C. The results showed that sensitivity (R_air/R_gas per ppm) goes on increasing with decreasing concentration of test gas, giving concentration dependent changes. Special studies carried out at low concentration levels (0.1-1 and 1-10 ppm) of H₂, give high sensitivity (200 × 10⁻³/ppm) for lowest concentration (0.1-1 ppm) of H₂. The selectivity for H₂ against relative humidity (RH), CO₂, CO and LPG gases is also good. The sensor, at operating temperature of 200 °C, is showing nearly zero response to 300 ppm of H₂, and offering response to acetone vapour of 11 ppm. Selectivity for acetone against RH% and CO₂ was also studied. These sensors can be used as H₂ sensor at an operating temperature of 265 °C, and as an acetone sensor at the operating temperature of 200 °C.     

具有负载电流检测的高速固态继电器接口电路设计

在姿轨控发动机地面试验中,需要控制快响应电磁阀的开闭,同时准确地测量负载电流。针对应用中的问题,实现了一种高速固态继电器接口电路。设计了用于各路控制信号隔离、逻辑判断和放大的数字控制电路,可切换共正/共负的负载模式,抑制感性负载反电势的负载电路,以及具有隔离输出的电流检测电路。误差分析和测试校准证明本电路对控制信号传输延时不超过150ns,电流检测精度达到0.2074%,可广泛适用于各种控制器与固态继电器的接口以及电流检测应用中。     

无线传感器网络的设计与部署

首先分析了无线传感器网络与传统无线自组织网络的区别,从侧面阐述了无线传感器网络的特点。接着,讨论了对无线传感器网络设计与部署具有指导意义的无线传感器网络的评价指标。最后,从无线传感器节点到无线传感器网络、从个体到整体、从微观到宏观,较为全面地讨论了无线传感器网络的设计与部署问题,为无线传感器网络的实际应用提供了有价值的参考。     

嵌入DeviceNet总线接口的智能差压传感器系统

介绍了一种具有DeviceNet现场总线通信功能的智能差压传感器的设计,探讨了传感器输入输出特性曲线的非线性校正方法。通过内嵌的总线控制器(SJA1000)、报文收发器(82C251)和P89C668单片机等,该传感器可直接作为一个DeviceNet从节点工作;对传感器的输入输出特性曲线进行了建模,以软件手段实现高精度的非线性自校正功能。测试结果表明:该智能差压传感器不但具有DeviceNet现场总线输出功能,且经过多项式或神经网络建模的传感器非线性误差分别可达0.04%FS和0.02%FS。这为高精度传感器的制作提供了一种可行的方法。     

调幅式电容位移传感器开关检波电路设计

针对调幅式电容位移传感器乘法器检波存在的速度慢、功耗大和热噪声大问题,设计了一种基于模拟开关的全波检波电路.首先,对开关全波检波和开关半波检波原理进行分析,根据分析结果选择了全波检波方法.在此基础上,完成开关全波检波电路设计与测量系统其它部分设计.最后,利用八位半数字表3458A对检波电路与测量系统性能指标进行测试.测试结果表明:检波电路可以实现0.1mV的分辨率,测量系统在150 ～650 μm范围内分辨率达30 nm,系统示值稳定性0.1mV/30 min,电容测量系统最大测量偏差为20 nm.该测量系统满足电容测微系统稳定性好、准确性高的要求.     

一种光纤传感器光源驱动电路的设计

半导体激光器作为光纤传感器的光源,其输出功率的稳定度直接影响着光纤传感器的准确度。根据光源的工作原理和输出特性,设计了一种应用于低温环境下的光源驱动电路。该电路基于自动功率控制(APC)原理,并引入了慢启动电路,有效防止了电源电压带来的干扰,延长了激光器的使用寿命。通过实验验证,该电路解决了激光器在使用中输出功率不稳定的问题,其稳定度优于0.5%,达到了较好的稳流效果。     

电路系统设计中电感式位移传感器的应用

十八世纪六十年代,第一次工业革命在英国发生,第一次工业革命不止是在英国社会工业上的一次变革,更代表着世界科学技术的一次重大变革.科学技术在不断发展,而在科学技术日益发达的当今社会,科学家开创了一个现代科技发达的社会,而传感器则是现代科技的领先者.对众多学科技术有着重大影响的一门高新技术.传感器的种类颇多、而且各类传感器是各具特点,选择的时候应该根据实际测量情况抉择,而设计一种合格的电感式传感器的要求也是很高的,由于各类传感器有着细微上的差别所以顾客购买时还需要注意一些事项.电感式位移传感器的发展迅速,现在广泛应用于各种测量检测仪器上.