Prognostics is seen as a key component of health usage monitoring systems, where prognostics algorithms can both detect anomalies in the behavior/performance of a micro-device/system, and predict its remaining useful life when subjected to monitored operational and environmental conditions. Light Emitting Diodes (LEDs) are optoelectronic micro-devices that are now replacing traditional incandescent and fluorescent lighting, as they have many advantages including higher reliability, greater energy efficiency, long life time and faster switching speed. For some LED applications there is a requirement to monitor the health of LED lighting systems and predict when failure is likely to occur. This is very important in the case of safety critical and emergency applications. This paper provides both experimental and theoretical results that demonstrate the use of prognostics and health monitoring techniques for high power LEDs subjected to harsh operating conditions. Full article

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. Full article