Understanding Smart Sensors - Nomads.usp

The Next Phase of Sensing Systems 327Design synthesisMask and processsynthesisShape synthesisfloor planningFabricationprocessMASKFabricationPhysicalrealizationSHAPEUseDesignedbehaviorFUNCTIONProcess simulation(extrusion)DistributedelementanalysisModel extractionLumpedelementanalysisDesign validationFigure 14.7 Combined electromechanical and mixed signal IC modeling. (After: [22].)One prior view of smart sensing proposed that a “smart sensor is definedas one that is capable of: (i) providing a digital output; (ii) communicatingthrough bi-directional digital bus; (iii) being accessed through a specificaddress; and (iv) executing commands and logical functions” [25]. The smartsensor also has desirable functions such as compensation of secondary parameters(e.g., temperature), failure prevention and detection, self-testing, autocalibration,and various computationally intensive operations. The emphasis oncomputing attributes in this definition necessitates a microcontroller as a minimumrequirement for a smart sensor.Another proposed definition stated that “a smart sensor consists of atransducer combined with other signal conditioning and other circuitry to produceoutput information signals that have been logically operated on toincrease the value of the information to the system” [26]. The aspects given inthis definition of added signal conditioning and increased information valueare noteworthy. The author lists sensor characteristics that take several sensorsfrom the simplest to smartest version, as illustrated in Figure 14.8.It is doubtful that either author of those two definitions would be satisfiedwith the definition proposed by the IEEE. However, the key to smart sensingwill be in the ability to satisfy users, not those making definitions. Sensor