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
Sensors Enabled by recent advances in mems technology Integrated Wireless Battery CPU Transceiver Limited in Energy Wireless Computation Transceiver ° Storage Transmission range Memory Bandwidth Sensing Hardware
Sensors • Enabled by recent advances in MEMS technology • Integrated Wireless Transceiver • Limited in • Energy • Computation • Storage • Transmission range • Bandwidth Battery Memory CPU Sensing Hardware Wireless Transceiver
Sensors M odern sensor nodes 1 32nds UC Berkeley: COTS Dust UC Berkeley: Smart Dust UC Berkeley: COTS Dust UCLA: WINS Rockwell: WINS JPL: Sensor Webs
Sensors
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Sensor Nodes
Sensors(contd The overall architecture of a sensor node consists of The sensor node processing subsystem running on sensor node main CPU The sensor subsystem and The communication subsystem The processor and radio board includes TI MSP430 microcontroller with 10kB RAM 16-bit RISC with 48K Program Flash IEEE 802. 15. 4 compliant radio at 250 Mbps 1MB external data flasl Runs Tinyos 1.1.10 or higher Two aa batteries or USB Crossbow mote 1.8 mA active); 5.1uA(sleep) TPR2400CA-TelosB
Sensors (contd.) • The overall architecture of a sensor node consists of: • The sensor node processing subsystem running on sensor node main CPU • The sensor subsystem and • The communication subsystem • The processor and radio board includes: • TI MSP430 microcontroller with 10kB RAM • 16-bit RISC with 48K Program Flash • IEEE 802.15.4 compliant radio at 250 Mbps • 1MB external data flash • Runs TinyOS 1.1.10 or higher • Two AA batteries or USB • 1.8 mA (active); 5.1uA (sleep) Crossbow Mote TPR2400CA-TelosB
Overall architecture of a sensor node Application Layer、 ensor Communication SubSystem Sensor node cpu Network Layer Slow serial link MAC Layer Physical layer Radio board Forward Packet path Wireless channe l
Overall Architecture of a Sensor Node Application Layer Network Layer MAC Layer Physical Layer Communication SubSystem Wireless Channel Slow Serial Link Sensor Sensor Node CPU Radio Board Forward Packet Path
