c8: sensor and sensor technology
TRANSCRIPT
8. 0 Sensor and sensing Technology
1.0 Objective
At the end of the lesson, student will be able to describe:
• Recognize sensor terminologies
• Types of sensor and sensor technology design consideration
• Function and application of sensor
Introduction A device which senses and detects the physical quantity of measurand and
converts to electrical form.• Example of sensors:• Mechanical : Bourdon tube pressure meter.• Electrical : Potentiometer• Optical : Photon counter• Chemical : Thermocouples
*All sensors are transducers but not all transducers are sensorsIn this lecture we also discuss
I. Sensors and the Environment
II. Sensor Development
III. Current Sensors – Terrestrial / Aquatic
IV. The next phase of In-Situ Sensors
V. Current Opportunities / Future Outlook
Sensor Technology - TerminologySensor Technology - Terminology
• Transducer is a device which transforms energy from one type to another, even if both energy types are in the same domain.– Typical energy domains are mechanical, electrical,
chemical, magnetic, optical and thermal.
• Transducer can be further divided into Sensors, which monitors a system and Actuators, which impose an action on the system.– Sensors are devices which monitor a parameter of a
system, hopefully without disturbing that parameter.
Sensor in control system
• In a simplified definition - an input of the required value of some variable and an output of the variable at the desired value.
CONTROL SYSTEM
INPUT
The required value of a variable
OUTPUT
The variable at the desired value
The Basic ElementsControl systems consist of the following essential elements, or components. • A measuring device which reacts to the machinery or process parameter to
be controlled, such as temperatures, pressure or rotational speed. • In its simplest form, where only a single measurement value is required, this
could be a temperature, pressure or centrifugal switch. For measurement throughout a whole range of values a transducer would be employed having all or some of the following components: – A sensing element which possesses some property which varied with changes in
the parameter to be measured. For instance, increasing temperature causes mechanical bending of a bi-metallic strip, increase in the electrical resistance of a coil of platinum wire and increase or decrease in the electrical resistance of a thermistor, depending on its type.
– A conversion device to produce an output signal in a form that the control system can use. There are standardised ranges of output signal so, in the above examples, a pneumatic signal in the pressure range 0.2 – 1.0 bar could be produced by the movement of the bi-metallic strip against a nozzle, or the resistance values could be converted to 4 – 20 mA current signals, or voltages in the 0 – 10 V resistance or thermocouple devices.
The Basic Elements• Conversion devices usually involve some degree of amplification of the
signal from the sensor and produce output signals which can be transmitted for some distance without loss of accuracy. For long distance transmission the signal must be converted to a form which does not loose accuracy even though the signal strength is diminished. This could be a frequency modulated (FM) voltage signal or a serial digital transmission.
– Compensation arrangements to protect the output signal from variation due to changes in parameters other than the one being measured. For instance, pressure transducers which employ strain gauges on diaphragms or tubes are provided with dummy gauges to compensate for changes in ambient temperature.
• A controller, which evaluates the deviation, i.e. the difference between the measured value and the desired value of the controlled condition (the set point value) and determines the output control signal, i.e. the setting of the actuator at any given time. Types and actions of controllers are discussed later.
• An actuator or other similar final controlling element, which performs the necessary correcting action, such as an electric motor to open or close a valve.
SensorsSensors
Definition: a device for sensing a physical variable of a physical system or an environment
Classification of Sensors• Mechanical quantities: displacement, Strain, rotation velocity, acceleration, pressure, force/torque, twisting, weight, flow• Thermal quantities: temperature, heat.• Electromagnetic/optical quantities: voltage, current, frequency phase; visual/images, light; magnetism.• Chemical quantities: moisture, pH value
Sensors
• USE: To understand and interpret the environment.• IN-SITU (vs. Remote): a) detectors at sight
b) higher resolution c) means to ground
truth
• DETECTION:a) physical – heat, pressure, humidity, light, sound
b) chemical – gas, liquid, solid, organics / inorganics
c) biological – gas signature, DNA, protein, acoustics
Categorization of SensorCategorization of Sensor
• Classification based on physical phenomena– Mechanical: strain gage, displacement (LVDT), velocity (laser
vibrometer), accelerometer, tilt meter, viscometer, pressure, etc.– Thermal: thermal couple– Optical: camera, infrared sensor– Others …
• Classification based on measuring mechanism– Resistance sensing, capacitance sensing, inductance sensing,
piezoelectricity, etc.
• Materials capable of converting of one form of energy to another are at the heart of many sensors. – Invention of new materials, e.g., “smart” materials, would permit
the design of new types of sensors.
Paradigm of Sensing System DesignParadigm of Sensing System Design
Zhang & Aktan, 2005
Instrumentation ConsiderationsInstrumentation Considerations
• Sensor technology;
• Sensor data collection topologies;
• Data communication;
• Power supply;
• Data synchronization;
• Environmental parameters and influence;
• Remote data analysis.
MeasurementMeasurement
Physical phenomenon
Measurement Output
Measurement output:• interaction between a sensor and the environment surrounding the sensor• compound response of multiple inputs
Measurement errors:• System errors: imperfect design of the measurement setup and the approximation, can be corrected by calibration• Random errors: variations due to uncontrolled variables. Can be reduced by averaging.
Specifications of SensorSpecifications of Sensor
• Accuracy: error between the result of a measurement and the true value being measured.
• Resolution: the smallest increment of measure that a device can make.
• Sensitivity: the ratio between the change in the output signal to a small change in input physical signal. Slope of the input-output fit line.
• Repeatability/Precision: the ability of the sensor to output the same value for the same input over a number of trials
Accuracy vs. PrecisionAccuracy vs. Precision
Precision without accuracy
Accuracy without precision
Precision and accuracy
Specifications of SensorSpecifications of Sensor
• Dynamic Range: the ratio of maximum recordable input amplitude to minimum input amplitude, i.e. D.R. = 20 log (Max. Input Ampl./Min. Input Ampl.) dB
• Linearity: the deviation of the output from a best-fit straight line for a given range of the sensor
• Transfer Function (Frequency Response): The relationship between physical input signal and electrical output signal, which may constitute a complete description of the sensor characteristics.
• Bandwidth: the frequency range between the lower and upper cutoff frequencies, within which the sensor transfer function is constant gain or linear.
• Noise: random fluctuation in the value of input that causes random fluctuation in the output value
Attributes of SensorsAttributes of Sensors• Operating Principle: Embedded technologies that make
sensors function, such as electro-optics, electromagnetic, piezoelectricity, active and passive ultraviolet.
• Dimension of Variables: The number of dimensions of physical variables.
• Size: The physical volume of sensors.• Data Format: The measuring feature of data in time;
continuous or discrete/analog or digital.• Intelligence: Capabilities of on-board data processing and
decision-making.• Active versus Passive Sensors: Capability of generating
vs. just receiving signals.• Physical Contact: The way sensors observe the
disturbance in environment.• Environmental durability: is the sensor robust enough
for its operation conditions
Consideration for Strain Gauges sensor Consideration for Strain Gauges sensor technolologytechnolology
• Foil strain gauge– Least expensive– Widely used– Not suitable for long distance– Electromagnetic Interference– Sensitive to moisture & humidity
• Vibration wire strain gauge– Determine strain from freq. of AC signal– Bulky
• Fiber optic gauge– Immune to EM and electrostatic noise– Compact size– High cost– Fragile
Strain SensingStrain Sensing
• Resistive Foil Strain Gage– Technology well developed; Low cost – High response speed & broad frequency
bandwidth– A wide assortment of foil strain gages
commercially available– Subject to electromagnetic (EM) noise,
interference, offset drift in signal. – Long-term performance of adhesives used for
bonding strain gages is questionable• Vibrating wire strain gages can NOT be
used for dynamic application because of their low response speed.
• Optical fiber strain sensor
Strain SensingStrain Sensing• Piezoelectric Strain Sensor
– Piezoelectric are ceramic-based or Piezoelectric polymer-based (e.g., PVDF)
– Very high resolution (able to measure nanostrain)– Excellent performance in ultrasonic frequency range, very high
frequency bandwidth; therefore very popular in ultrasonic applications, such as measuring signals due to surface wave propagation
– When used for measuring plane strain, can not distinguish the strain in X, Y direction
– Piezoelectric ceramic is a brittle material (can not measure large deformation)
Courtesy of PCB Piezotronics
Acceleration SensingAcceleration Sensing
• Piezoelectric accelerometer– Nonzero lower cutoff frequency (0.1 – 1 Hz for 5%)– Light, compact size (miniature accelerometer weighing
0.7 g is available)– Measurement range up to +/- 500 g– Less expensive than capacitive accelerometer– Sensitivity typically from 5 – 100 mv/g– Broad frequency bandwidth (typically 0.2 – 5 kHz)– Operating temperature: -70 – 150 C
Photo courtesy of PCB Piezotronics
Acceleration SensingAcceleration Sensing
• Capacitive accelerometer– Good performance over low frequency range, can measure
gravity!– Heavier (~ 100 g) and bigger size than piezoelectric
accelerometer– Measurement range up to +/- 200 g– More expensive than piezoelectric accelerometer– Sensitivity typically from 10 – 1000 mV/g– Frequency bandwidth typically from 0 to 800 Hz– Operating temperature: -65 – 120 C
Photo courtesy of PCB Piezotronics
AccelerometerAccelerometer
Force SensingForce Sensing
• Metal foil strain-gage based (load cell)– Good in low frequency response– High load rating– Resolution lower than piezoelectricity-based– Rugged, typically big size, heavy weight
Courtesy of Davidson Measurement
Force SensingForce Sensing
• Piezoelectricity based (force sensor)– lower cutoff frequency at 0.01 Hz
• can NOT be used for static load measurement
– Good in high frequency– High resolution– Limited operating temperature (can not be used for high
temperature applications)– Compact size, light
Courtesy of PCB Piezotronics
Displacement SensingDisplacement Sensing
• LVDT (Linear Variable Differential Transformer):– Inductance-based electromechanical
sensor– “Infinite” resolution
• limited by external electronics– Limited frequency bandwidth (250 Hz
typical for DC-LVDT, 500 Hz for AC-LVDT)– No contact between the moving core and
coil structure • no friction, no wear, very long operating
lifetime– Accuracy limited mostly by linearity
• 0.1%-1% typical– Models with strokes from mm’s to 1 m
available
Photo courtesy of MSI
Displacement SensingDisplacement Sensing
• Linear Potentiometer
– Resolution (infinite), depends on?– High frequency bandwidth (> 10 kHz)– Fast response speed– Velocity (up to 2.5 m/s)– Low cost– Finite operating life (2 million cycles) due to contact
wear– Accuracy: +/- 0.01 % - 3 % FSO– Operating temperature: -55 ~ 125 C
Photo courtesy of Duncan Electronics
Displacement TransducerDisplacement Transducer
• Magnetostrictive Linear Displacement Transducer– Exceptional performance for long stroke position measurement
up to 3 m– Operation is based on accurately measuring the distance from a
predetermined point to a magnetic field produced by a movable permanent magnet.
– Repeatability up to 0.002% of the measurement range. – Resolution up to 0.002% of full scale range (FSR)– Relatively low frequency bandwidth (-3dB at 100 Hz)– Very expensive– Operating temperature: 0 – 70 C
Photo courtesy of Schaevitz
Displacement SensingDisplacement Sensing
• Differential Variable Reluctance Transducers – Relatively short stroke– High resolution– Non-contact between the measured object and sensor
Type of Construction Standard
tubular
Fixing Modeby 8mm
diameter
Total Measuring Range
2(+/-1)mm
Pneumatic Retraction No
Repeatability 0.1um
Operating Temperature Limits
-10 to +65 degrees C
Courtesy of Microstrain, Inc.
Velocity SensingVelocity Sensing
• Scanning Laser Vibrometry – No physical contact with the test object; facilitate remote,
mass-loading-free vibration measurements on targets – measuring velocity (translational or angular)– automated scanning measurements with fast scanning speed – However, very expensive
Photo courtesy of Bruel & Kjaer
Photo courtesy of Polytec
Shock (high-G) SensingShock (high-G) Sensing
• Shock Pressure Sensor– Measurement range up to 69 MPa (10 ksi)– High response speed (rise time < 2 sec.)– High frequency bandwidth (resonant
frequency up to > 500 kHz) – Operating temperature: -70 to 130 C– Light (typically weighs ~ 10 g)
• Shock Accelerometer– Measurement range up to +/- 70,000 g– Frequency bandwidth typically from 0.5 –
30 kHz at -3 dB– Operating temperature: -40 to 80 C– Light (weighs ~ 5 g)
Photo courtesy of PCB Piezotronics
Angular Motion Sensing (Tilt Meter)Angular Motion Sensing (Tilt Meter)
• Inertial Gyroscope (e.g., http://www.xbow.com)– used to measure angular rates and X, Y, and Z acceleration.
• Tilt Sensor/Inclinometer (e.g., http://www.microstrain.com)– Tilt sensors and inclinometers generate an artificial horizon and
measure angular tilt with respect to this horizon.
• Rotary Position Sensor (e.g., http://www.msiusa.com)– includes potentiometers and a variety of magnetic and capacitive
technologies. Sensors are designed for angular displacement less than one turn or for multi-turn displacement.
Photo courtesy of MSI and Crossbow
http://www.gmu.edu/departments/seor/student_project/syst101_00b/team07/components.html
Micro-Electric Mechanical Systems (MEMS)
– receives data, processes it, decides what to do based on data
-gathers biological, chemical, physical environmental data
(brains)
(eyes, nose, ears . . .)
- act as a switch or trigger, activate external device.
- valves, pumps, micro-fluidics
MEMS TechnologyMEMS Technology
• What is MEMS?– Acronym for Microelectromechanical Systems– “MEMS is the name given to the practice of making and
combining miniaturized mechanical and electrical components.”– K. Gabriel, SciAm, Sept 1995.
• Synonym to:– Micromachines (in Japan)– Microsystems technology (in Europe)
• Leverage on existing IC-based fabrication techniques (but now extend to other non IC techniques)– Potential for low cost through batch fabrication– Thousands of MEMS devices (scale from ~ 0.2 m to 1 mm)
could be made simultaneously on a single silicon wafer
MEMS TechnologyMEMS Technology
• Co-location of sensing, computing, actuating, control, communication & power on a small chip-size device
• High spatial functionality and fast response speed– Very high precision in manufacture– miniaturized components improve
response speed and reduce power consumption
MEMS Fabrication Technique
Courtesy of A.P. Pisano, DARPA
Distinctive Features of MEMS DevicesDistinctive Features of MEMS Devices
• Miniaturization– micromachines (sensors and actuators) can handle
microobjects and move freely in small spaces
• Multiplicity– cooperative work from many small micromachines
may be best way to perform a large task– inexpensive to make many machines in parallel
• Microelectronics– integrate microelectronic control devices with sensors
and actuators Fujita, Proc. IEEE, Vol. 86, No 8
MEMS AccelerometerMEMS Accelerometer
• Capacitive MEMS accelerometer– High precision dual axis
accelerometer with signal conditioned voltage outputs, all on a single monolithic IC
– Sensitivity from 20 to 1000 mV/g
– High accuracy– High temperature stability – Low power (less than 700 uA
typical) – 5 mm x 5 mm x 2 mm LCC
package – Low cost ($5 ~ $14/pc.)
Courtesy of Analog Devices, Inc.
MEMS Accelerometer
• Piezoresistive MEMS accelerometer– Operating Principle: a proof mass attached to a silicon
housing through a short flexural element. The implantation of a piezoresistive material on the upper surface of the flexural element. The strain experienced by a piezoresistive material causes a position change of its internal atoms, resulting in the change of its electrical resistance
– low-noise property at high frequencies
Courtesy of JP Lynch, U Mich.
MEMS Dust • MEMS dust here has the same scale as a
single seed - something so small and light that it literally floats in the air.
Source: Distributed MEMS: New Challenges for Computation, by A.A. BERLIN and K.J. GABRIEL, IEEE Comp. Sci. Eng., 1997
Major Ecological Focal Points• GLOBAL CHANGE
– Nature and pace of climate change? * Requires – A global heat and water balance (ocean, land, atm)
– Nature and pace of biological change? * Requires – census of life & functional role of biodiversity
Who’s there? How many? What are they doing?
• BIOCOMPLEXITY– Understanding patterns & processes across
a) levels of organization: molecular global b) across space and time: arctic tropical
http://www.dynamax.com/
• FUNCTION: Measures Sap Velocity g/hr (transpiration)
• APPLICATION: herbs, grasses, shrubs, trees
• PRINCIPLE: thermocouples (heat), plant energy balance
• PROS: Real-Time, No calibration, non-intrusive
• CONS: need many, not wireless
• COMPANY: Dynamax, Advanced Measurements and Controls Inc, Delta-T
• COST: $200 - $3500+
Sap Flow Sensors
- http://www.lotek.com/
• FUNCTION: Organism tracking & Sensing
• APPLICATION: Birds, Bats, Fish, Reptiles, Mammals
• PRINCIPLE: Micro-sensors (position, pressure, temp), Radio & Acoustic waves
• PROS: Wireless, Small, Long use history, No calibration, Real-time option
• CONS: Intrusive, Power limitations
• COMPANY: Lotek, Telonics Inc, Holohil Systems Ltd
• COST: $135 - $350+
Radio & Acoustic Telemetry
http://www.holohil.com/lb2pic.htm
http://www.bartztechnology.com/products.htm
• FUNCTION: Soil observatory
• APPLICATION: Soils, Root studies, Soil fauna
• PRINCIPLE: Video, Magnification
• PROS: Non-destructive, Small, 100xmagnification, soon Automated
• CONS: Manual, Physical data only
• COMPANY: Bartz Technology
• COST: $13,000 - $16,500+
Minirhizotron
• FUNCTION: 3-D ground mapping
• APPLICATION: Soils, Roots, Groundwater, Rocks,
Nests, Forests, Lakes, Deserts, Ice . . .
• PRINCIPLE: EM wave propagation
• PROS: Non-invasive, Rapid, Hi-resolution, Long use history
• CONS: Depth limitation,
• COMPANY: Sensors & Software Inc., GeoModel, Inc.
• COST: varies
http://www.uwec.edu/jolhm/research/Brian/what_is_ground_penetrating_radar.htm
Ground Penetrating Radar (GPR)
Physical Biological Chemical
Aquatic Environments
http://www.hydrolab.com/
• FUNCTION: Measures 15 or more parameters including: Temperature, pH, Nutrients, Gas, Chlorophyll
• APPLICATION: Fresh & Marine water (physical, chemical)
• PRINCIPLE: Sensor cluster & Datalogger
• PROS: Multiple parameters simultaneously, Automated
• CONS:
• COMPANY: Hydrolab, In-Situ Inc, Advanced Measurements and Controls Inc.
• COST: $3000 - $4000+
Multi-Parameter Sondes
http://www.rdinstruments.com/ • FUNCTION: Currant and Wave velocity profiler
• APPLICATION: Oceans, Rivers, Discharge
• PRINCIPLE: Doppler shift
• PROS: Real-time, Quick & Accurate
• CONS:
• CONTACTS: RD Instruments, Nortek, Sontek
• COST: $15,000 - $23,000
Acoustic Doppler Current Profiler
Wireless Moored ProfilerWireless Moored Profiler
http://www.dsl.whoi.edu/DSL/dana/abe_cutesy.html
• FUNCTION: Automated ocean surveyors
• APPLICATION: Deep ocean surveys
• PRINCIPLE:Video, Temp, Salinity, Magnetometer, Optical backscatter, Acoustic altimeter
• PROS: ‘Smart’, Autonomous, Multiple parameters
• CONS: Prototype
• COMPANY: Dana R. Yoerger - WHOI
Autonomous Underwater Vehicles (AUV)
Autonomous Benthic Explorer (ABE)
http://science.whoi.edu/users/sgallager/vprwebsite/vprdraft.html
• FUNCTION: Autonomous plankton observatory
• APPLICATION: Oceans, Estuaries, Lakes
• PRINCIPLE: Video, Sensors
• PROS: Plankton imaged & environmental data measured, ‘real time’, autonomous
• CONS: Prototype
• COMPANY: Scott Gallager - WHOI
Video Plankton Recorder
http://www.nsf.gov/od/lpa/news/press/01/pr0130_progress.htm
• FUNCTION: Aquatic biological assessment & physical parameters
• APPLICATION: Oceans, Coasts
• PRINCIPLE: Acoustic & Optical sensors, CTD Fluorescence, Salinity
• PROS: Robust biological assessment & Environmental data
• CONS: Prototype
• COMPANY: Peter Wiebe - WHOI
BIOMAPER II (BIo- Optical Multifrequency Acoustical and
Physical Environmental Recorder )
• FUNCTION: Acoustical, Physiological, and Environmental data (6-9 hrs)
• APPLICATION: Marine mammals (whales, dolphins, manatees etc)
• PRINCIPLE: Micro-sensors (pressure, hydrophone, temp, accelerometer) VHF radio beacon
• PROS: Non-invasive, Compact, Re-useable, Over 2000m depth, Tag potted in epoxy,
• CONS: Suitability depends upon Movement and Skin quality, Challenging to apply• COMPANY: Mark Johnson – WHOI
• COST: $10,000 – $15,000
http://dtag.whoi.edu/tag.html
Digital Whale Tag
Photos: Copyright, Woods Hole Oceanographic Institution, The DTAG Project. Mark Johnson and Peter Tyack, funded by ONR, NMFS, WHOI.
• FUNCTION: Pressure, Temperature, Micro-hygrometer, Radiation Densitometer, Laser Doppler anemometer
• APPLICATION: in-situ microclimate data
• PRINCIPLE: Micro-sensor clusters
• PROS: Accuracy, Fast response, Low mass & Volume, Cheap
• CONS: not yet available
• COMPANY: JPL, GWU
• COST: will be relatively cheap
Mini-weather stations
Micro-hygrometer
JPL - http://www.jpl.nasa.gov/technology/
BATTERIES DRAIN
LED PD
MICRO-SENSORCLUSTER
(Temp, Pressure & Humidity)
ANTENNAINSIDE
BATTERYCOMPARTMENT
RAIN GAGE
WIND GAGE
CYLINDRICALPLASTICHOUSING
MICROCONTROLLER
FIVE CENTIMETERDIAMETERM
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$50
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COMPANY - GWU
•Alkanes
•Cyclo-Alkanes
•Alkenes
•Alcohols
•Aromatics
•Ketones
•Esters
•Organo Phosphonates
•Pesticides
•Amines
•Pyridines
•Phenols
•Organic Acids
•Aldehydes
•Halides
- http://www.femtoscan.com/evm.htm
• FUNCTION: Vapor detector
• APPLICATION: Trace gases emissions
• PRINCIPLE: Ion mobility spectrometry, Gas chromatography
• PROS: Real-time, No carrier gas, ppb sensitivity, Hand portable, Reliable, Good reproducibility
• CONS: Expensive
• COMPANY: Femtoscan, HAPSITE
• COST:
Portable Gas Chromatograph
http://www.sandia.gov/media/NewsRel/NR2000/labchip.htm
• FUNCTION: Autonomous chemical detector
• APPLICATION: Gas, Liquid, DNA
• PRINCIPLE: GC/LC separator & coated SAW array
• PROS: Ppb level detection, Gas & Liquid, Small
• CONS: not yet available
• COMPANY: Sandia, Eksigent Technologies
• COST: ~$5000
Chem-lab on a chip
• FUNCTION: ID gases and quantify concentrations (ppb- ppt)
• APPLICATION: Air, Water, Soil, Plant volatiles. . .
• PRINCIPLE: SAW sensor(s) & Micro-GC
• PROS: Quick (10 sec), Small, Sensitivity, Remote option
• CONS:
• COMPANY: Estcal, JPL
• COST: $19, 450 - $24, 950+
http://www.estcal.com/Products.html
Electronic Nose (s)zNose ©
http://www.businessplans.org/Vusion/Vusion00.html
• FUNCTION: ID chemical composition of liquids
• APPLICATION: Dissolved organics & inorganics, Aquatic mold growth, Soil analysis
• PRINCIPLE: 100’s of microsensors on chip, Colors change depending on chemicals, Results read by camera on a chip
• PROS: Cheap, Disposable, Qualitative, Quantitative, Several analyses simultaneously
• CONS: not commercially available in US
• COMPANY: ALPHA M.O.S, Vusion, Inc. UT Austin, JPL
• COST: Inexpensive
http://www.alpha-mos.com/proframe.htm
Electronic Tongue
• FUNCTION: Wireless microsensor clusters for Spacial and Temperal monitoring
• APPLICATION: Terrestrial, Atmosphere, Gases
• PRINCIPLE: Microsensor clusters, RF telemetry
• PROS: Small, Wireless, Low power, Custom sensor design, Affordable, Available, Information shared between pods
• CONS:
• COMPANY: Kevin Delin – JPL
• COST: $750 / pod
Sensor Webs
Nano-Technology
• Nano-scale size
• Constructed atom / molecule at a time
• Self-repairing
• Self-assembling – ex. carbon nanotubes
• Molecular switches (transistor) - UCLA
• Model – nature
• Still in development phase
Home Interior Flowchart
MCUTI MSP430F149
Touch Sensors
RS-485 Transceiver
1 Mb Flash
LCD Display
USB Endpoint
8-bit Parallel Bus SPI Bus
DigitalPotentiometer
MCUTI MSP430F169
RS-485 Transceiver
USB
USB Endpoint
US
B
Optional USB alternative to RS-485 / Base Station
RS
-48
5 B
usQuadrature
Encoders
PW
M
Level 1/ Base Station Block Diagram
Areas of Opportunity• Technological overlaps with NASA, DoE, DoD
• Opportunity to custom design arrays of sensor clusters – Sensors can be chosen specific to the research
question
• View interactions between levels of organization
• Technological outlook– Micro-technology: Present - 5+ years – Nano-technology: 5 - 10+ years:
Future Directions
• Power
• Automated data assimilation & analysis
• Decreased costs– Maintenance-free– Long-term
• Increased miniaturization
Smart Sensor Web
Sap Flow Sensor Array
MinirhizotronArray
Multiparameter Soil Probes
‘Smart Dust’ tagged Insects Automated E-tongue
Sensor Clustered MEMS Insects
RF Telemetry Macro-organisms
Instrumenting the Environment
Micro-weather Stations
E-nose
Sensor Industry
• ADVANCES: smaller, faster, cheaper, decreased power demand, ‘smart’, wireless . . .
• INDUSTRY:
a) Over 100 properties can be sensed
b) Over 2300 sensor suppliers . . .
Major Areas of Sensor Development
• Governmental – DoD– DoE– NASA– NOAA– Health
• Private Sector– Communications– Electronics– Industrial
Focus - miniaturization - automation - bio / chem detection - environmental sensing - decreased power - faster - ‘smarter’ - wireless - remote / in-situ
Examples of Micro-Sensor Cluster Groups
• UC Berkeley – COTS – ‘Smart Dust’
• Michigan - WIMS (Wireless Integrated Micro Systems)
• GWU - ‘Mini Weather Stations’
• NASA - JPL – Sensor Webs
• DoE – Sandia, Oak Ridge
• DoD – Naval Research Lab
References
Zhang, R. and Aktan, E., “Design consideration for sensing systems to ensure data quality”, Sensing issues in Civil Structural Health Monitoring, Eded by Ansari, F., Springer, 2005, P281-290
Structural health monitoring using scanning laser vibrometry,” by L. Mallet, Smart Materials & Structures, vol. 13, 2004, pg. 261