Selected examples of intelligent (micro) sensor systems: state-of-the-art and tendencies

The capability of intelligent sensors to have more intelligence built into them continues to drive their application in areas including automotive, aerospace and defense, industrial, intelligent house and wear, medical and homeland security. In principle It is difficult to overestimate the importance of intelligent (micro) sensors or sensor systems within advanced societies but one characteristic feature is the global market for sensors, which is now about $20 billion annually. Therefore sensors or sensor systems play a dominant role in many fields from the macro sensor in manufacturing industry down to the miniaturized sensor for medical applications. The diversity of sensors precludes a complete description of the state-of-the-art; selected examples will illustrate the current situation. MEMS (microelectromechanical systems) devices are of special interest in the context of micro sensor systems. In past the main requirements of a sensor were in terms of metrological performance. The electrical (or optical) signal produced by the sensor needed to match the measure relatively accurately. Such basic functionality is no longer sufficient. Data processing near the sensor, the extraction of more information than just the direct sensor information by signal analysis, system aspects and multi-sensor information are the new demands. A shifting can be observed away from aiming to design perfect single-function transducers and towards the utilization of system-based sensors as system components. In the ideal case such systems contain sensors, actuators and electronics. They can be realized in monolithic, hybrid or discrete form-which kind is used depends on the application. In this article the state-of-the-art of intelligent sensors or sensor systems is reviewed using selected examples. Future trends are deduced.