Development of a microelectromechanical system (MEMS)-based multisensor platform for environmental monitoring

Recent progress in data processing, communications and electronics miniaturization is now enabling the development of low-cost wireless sensor networks (WSN), which consist of spatially distributed autonomous sensor modules that collaborate to monitor real-time environmental conditions unobtrusively and with appropriate levels of spatial and temporal granularity. Recent and future applications of this technology range from preventative maintenance and quality control to environmental modelling and failure analysis. In order to fabricate these low-cost, low-power reliable monitoring platforms, it is necessary to improve the level of sensor integration available today. This paper outlines the microfabrication and characterization results of a multifunctional multisensor unit. An existing fabrication process for Complementary Metal Oxide Semiconductor CMOS-compatible microelectromechanical systems (MEMS) structures has been modified and extended to manufacture temperature, relative humidity, corrosion, gas thermal conductivity, and gas flow velocity sensors on a single silicon substrate. A dedicated signal conditioning circuit layer has been built around this MEMS multisensor die for integration on an existing low-power WSN module. The final unit enables accurate readings and cross-sensitivity compensation thanks to a combination of simultaneous readings from multiple sensors. Real-time communication to the outside world is ensured via radio-frequency protocols, and data collection in a serial memory is also made possible for diagnostics applications

Miniaturised multi-MEMS sensor development

This paper describes the design, fabrication and initial characterisation of a MEMS-based environmental monitoring system. Intended for use with miniaturised Wireless Sensor Network (WSN) motes, the die measures 3 × 3 mm and incorporates humidity, temperature, corrosion, gas and gas flow velocity sensors on a single substrate. Fabricated using a combination of surface and bulk micromachining technologies, the sensor system is designed to replace discrete components on WSN module boards, thereby minimising space consumption and enabling smaller, cheaper wireless motes. Sensors have been characterised over a wide range of environmental conditions. An analysis of the effects of changes in environmental parameters other than the measurand of interest on the performance of the temperature and humidity sensors has been carried out, and corrections applied where necessary. A variety of corrosion monitors have been demonstrated. A gas flow velocity sensor, based on forced convective heat transfer and which has been thermally isolated from the silicon substrate in order to reduce power consumption and improve sensitivity at low flow-rates, has also been presented. The paper also outlines the design of the next generation sensing platform using the novel 10 mm wireless cube developed at Tyndall

Wireless Sensor Network for Forest Fire Detection

 Forest fires are one of problems that threaten sustainability of the forest. Early prevention system for indications of forest fires is absolutely necessary. The extent of the forest to be one of the problems encountered in the forest condition monitoring. To overcome the problems of forest extent, designed a system of forest fire detection system by adopting the Wireless Sensor Network (WSN) using multiple sensor nodes. Each sensor node has a microcontroller, transmitter/receiver and three sensors. Measurement method is performed by measuring the temperature, flame, the levels of methane, hydrocarbons, and CO2 in some forest area and the combustion of peat in a simulator. From results of measurements of temperature, levels of methane, a hydrocarbon gas and CO2 in an open area indicates there are no signs of fires due to the value of the temperature, methane, hydrocarbon gas, and CO2 is below the measurement in the space simulator

Toward a unified PNT, Part 1: Complexity and context: Key challenges of multisensor positioning

The next generation of navigation and positioning systems must provide greater accuracy and reliability in a range of challenging environments to meet the needs of a variety of mission-critical applications. No single navigation technology is robust enough to meet these requirements on its own, so a multisensor solution is required. Known environmental features, such as signs, buildings, terrain height variation, and magnetic anomalies, may or may not be available for positioning. The system could be stationary, carried by a pedestrian, or on any type of land, sea, or air vehicle. Furthermore, for many applications, the environment and host behavior are subject to change. A multi-sensor solution is thus required. The expert knowledge problem is compounded by the fact that different modules in an integrated navigation system are often supplied by different organizations, who may be reluctant to share necessary design information if this is considered to be intellectual property that must be protected

The CLARITY modular ambient health and wellness measurement platform

Emerging healthcare applications can benefit enormously from recent advances in pervasive technology and computing. This paper introduces the CLARITY Modular Ambient Health and Wellness Measurement Platform:, which is a heterogeneous and robust pervasive healthcare solution currently under development at the CLARITY Center for Sensor Web Technologies. This intelligent and context-aware platform comprises the Tyndall Wireless Sensor Network prototyping system, augmented with an agent-based middleware and frontend computing architecture. The key contribution of this work is to highlight how interoperability, expandability, reusability and robustness can be manifested in the modular design of the constituent nodes and the inherently distributed nature of the controlling software architecture.Emerging healthcare applications can benefit enormously from recent advances in pervasive technology and computing. This paper introduces the CLARITY Modular Ambient Health and Wellness Measurement Platform:, which is a heterogeneous and robust pervasive healthcare solution currently under development at the CLARITY Center for Sensor Web Technologies. This intelligent and context-aware platform comprises the Tyndall Wireless Sensor Network prototyping system, augmented with an agent-based middleware and frontend computing architecture. The key contribution of this work is to highlight how interoperability, expandability, reusability and robustness can be manifested in the modular design of the constituent nodes and the inherently distributed nature of the controlling software architecture

Application of Smart Solid State Sensor Technology in Aerospace Applications

Aerospace applications require a range of chemical sensing technologies to monitor conditions in both space vehicles and aircraft operations. One example is the monitoring of oxygen. For example, monitoring of ambient oxygen (O2) levels is critical to ensuring the health, safety, and performance of humans living and working in space. Oxygen sensors can also be incorporated in detection systems to determine if hazardous leaks are occurring in space propulsion systems and storage facilities. In aeronautic applications, O2 detection has been investigated for fuel tank monitoring. However, as noted elsewhere, O2 is not the only species of interest in aerospace applications with a wide range of species of interest being relevant to understand an environmental or vehicle condition. These include combustion products such as CO, HF, HCN, and HCl, which are related to both the presence of a fire and monitoring of post-fire clean-up operations. This paper discusses the development of an electrochemical cell platform based on a polymer electrolyte, NAFION, and a three-electrode configuration. The approach has been to mature this basic platform for a range of applications and to test this system, combined with "Lick and Stick" electronics, for its viability to monitor an environment related to astronaut crew health and safety applications with an understanding that a broad range of applications can be addressed with a core technology

A Low Cost Multi-sensor Strategy for Early Warning in Structural Monitoring Exploiting a Wavelet Multiresolution Paradigm

AbstractThis paper deals with a novel approach to validate alerts provided by an early warning system (EWS) for structural monitoring implemented through low cost multi-sensor nodes. In particular, a dedicated wavelet multiresolution methodology is presented to implement a reliable assessment of the structural behavior. Such strategy allows to discriminate the structural response to seismic sources from other exogenous inertial components. Results obtained demonstrate the suitability of the proposed solution in the framework of the development of low cost multi-sensor strategies for the early warning of anomalous structural behaviors

InContexto: Multisensor Architecture to Obtain People Context from Smartphones

The way users intectact with smartphones is changing after the improvements made in their embedded sensors. Increasingly, these devices are being employed as tools to observe individuals habits. Smartphones provide a great set of embedded sensors, such as accelerometer, digital compass, gyroscope, GPS, microphone, and camera. This paper aims to describe a distributed architecture, called inContexto, to recognize user context information using mobile phones. Moreover, it aims to infer physical actions performed by users such as walking, running, and still. Sensory data is collected by HTC magic application made in Android OS, and it was tested achieving about 97% of accuracy classifying five different actions (still, walking and running).This work was supported in part by Projects CICYT TIN2011-28620-C02-01, CICYT TEC2011-28626-C02-02, CAM CONTEXTS (S2009/TIC-1485), and DPS2008-07029- C02-02.Publicad

Ceramic MEMS Designed for Wireless Pressure Monitoring in the Industrial Environment

This paper presents the design of a wireless pressure-monitoring system for harsh-environment applications. Two types of ceramic pressure sensors made with a low-temperature cofired ceramic (LTCC) were considered. The first type is a piezoresistive strain gauge pressure sensor. The second type is a capacitive pressure sensor, which is based on changes of the capacitance values between two electrodes: one electrode is fixed and the other is movable under an applied pressure. The design was primarily focused on low power consumption. Reliable operation in the presence of disturbances, like electromagnetic interference, parasitic capacitances, etc., proved to be contradictory constraints. A piezoresistive ceramic pressure sensor with a high bridge impedance was chosen for use in a wireless pressure-monitoring system and an acceptable solution using energy-harvesting techniques has been achieved. The described solution allows for the integration of a sensor element with an energy harvester that has a printed thick-film battery and complete electronics in a single substrate packaged inside a compact housing