Sensors and wireless Sensor networks
Sensors and Wireless Sensor Networks
Roadmap Motivation for a network of wireless sensor nodes Definitions and background Challenges and constraints Overview of topics covered
Roadmap • Motivation for a Network of Wireless Sensor Nodes • Definitions and background • Challenges and constraints • Overview of topics covered
Sensing and sensors Sensing: technique to gather information about physical objects or areas Sensor(transducer): object performing a sensing task; converting one form of energy in the physical world into electrical energy Examples of sensors from biology: the human body eyes: capture optical information(light) ears: capture acoustic information(sound) nose: captures olfactory information(smell) skin: captures tactile information(shape, texture
Sensing and Sensors • Sensing: technique to gather information about physical objects or areas • Sensor (transducer): object performing a sensing task; converting one form of energy in the physical world into electrical energy • Examples of sensors from biology: the human body • eyes: capture optical information (light) • ears: capture acoustic information (sound) • nose: captures olfactory information (smell) • skin: captures tactile information (shape, texture)
Sensing Data Acquisition Conditioning Analog-to-Digital Converter Sensing Actuator ;. Conditioning ;. Digital-to-analog y Actuation Sensors capture phenomena in the physical world(process, system, plant Signal conditioning prepare captured signals for further use( amplification, attenuation filtering of unwanted frequencies etc Analog-to-digital conversion (ADC) translates analog signal into digital sign Digital signal is processed and output is often given via digital-analog converter and signal conditioner) to an actuator device able to control the physical world
Sensing (Data Acquisition) • Sensors capture phenomena in the physical world (process, system, plant) • Signal conditioning prepare captured signals for further use (amplification, attenuation, filtering of unwanted frequencies, etc.) • Analog-to-digital conversion (ADC) translates analog signal into digital signal • Digital signal is processed and output is often given (via digital-analog converter and signal conditioner) to an actuator (device able to control the physical world)
Sensor classifications Physical property to be monitored determines type of required sensor Type Examples Temperature hermistors, thermocouples Pressure Pressure gauges, barometers, ionization gauges Optical Photodiodes, phototransistors, infrared sensors, CCD sensors Acoustic Piezoelectric resonators, microphones Mechanical Strain gauges, tactile sensors, capacitive diaphragms, piezoresistive cells Motion vibration Accelerometers mass air flow sensors Position GPS, ultrasound-based sensors infrared-based sensors inclinometers Electromagnetic Hall-effect sensors magnetometers Chemical pH sensors, electrochemical sensors, infrared gas sensors Humidity Capacitive and resistive sensors hygrometers, mEMs-based humidity sensors Radiation lonization detectors, Geiger-Mueller counters
Sensor Classifications • Physical property to be monitored determines type of required sensor Type Examples Temperature Thermistors, thermocouples Pressure Pressure gauges, barometers, ionization gauges Optical Photodiodes, phototransistors, infrared sensors, CCD sensors Acoustic Piezoelectric resonators, microphones Mechanical Strain gauges, tactile sensors, capacitive diaphragms, piezoresistive cells Motion, vibration Accelerometers, mass air flow sensors Position GPS, ultrasound-based sensors, infrared-based sensors, inclinometers Electromagnetic Hall-effect sensors, magnetometers Chemical pH sensors, electrochemical sensors, infrared gas sensors Humidity Capacitive and resistive sensors, hygrometers, MEMS-based humidity sensors Radiation Ionization detectors, Geiger-Mueller counters