Wireless Ad Hoc and Sensor Networks

Background on Networking 43TABLE 1.4Physical Principles and MeasurandsMeasurements of Wireless Sensors NetworksMeasurandPrinciplePhysical properties Pressure Piezoresistive, capacitiveTemperature Thermistor, thermomechanical,thermocoupleHumidityResistive, capacitiveFlowPressure change, thermistorMotion properties Position E-mag, GPS, contact sensorVelocityDoppler, Hall effect, optoelectronicAngular velocity Optical encoderAcceleration Piezoresistive, piezoelectric, optical fiberContact properties Strain PiezoresistiveForcePiezoelectric, piezoresistiveTorquePiezoresistive, optoelectronicSlipDual torqueVibrationPiezoresistive, piezoelectric, optical fiber,sound, ultrasoundPresence Tactile/contact Contact switch, capacitiveProximityHall effect, capacitive, magnetic, seismic,acoustic, RFDistance/range E-mag (sonar, radar, lidar), magnetic,tunnelingMotionE-mag, IR, acoustic, seismic (vibration)Biochemical Biochemical agents Biochemical transductionIdentification Personal features VisionPersonal ID Fingerprints, retinal scan, voicethe Web sites of SUNX Sensors, Schaevitz, Keyence, Turck, Pepperl &Fuchs, National Instruments, UE Systems (ultrasonic), Leake (IR), CSI(vibration). Table 1.4 shows which physical principles may be used tomeasure various quantities. MEMS sensors are by now available for mostof these measurands.1.5.4 Commercially Available Wireless Sensor SystemsMany wireless communication nodes are commercially available, includingLynx technologies, and various Bluetooth kits, including the Casiradevices from Cambridge Silicon Radio, CSR.Crossbow Berkley Motes: They may be the most versatile WSNdevices on the market for prototyping purposes. Crossbow