sensors presentation-06a

Sensors: Getting Engaged!


EventI/O: The Museum Inside-Out/Outside-In38th Annual MCN ConferenceAustin, TexasPresented byAbhijit RaoPlan A Computing AssociatesThere has been this surge in Wireless Sensors it is a reasonable mature market it is not anymore confined to the walls of an R& D Lab. We will look at some of the detail including the internals of a sensor, the structure etc,. the emerging uses, what has propelled their growth and how to use them. We take a look couple of potential applications and the framework. Other than sensors- affordable computing systems, mobile devices and wireless technologies are fueling the growth new possibilities in exploring and learning.Sensors will drive the next surge of innovation in Museums. With the advances in semiconductor technology, various sensors such as temperature, motion sensing, pressure, humidity, compass, touch and proximity are being made affordable and easy to use. Sensors will allow the museum to present the visitor with a whole new world of interactivity / engagement. Various forms of Wireless connectivity available today only make it more convenient to design and manage. This lecture will provide an introduction to the digital sensors- their characteristics and then the selection process. Also covered will be the common requirements to be considered in selecting wireless connectivity techniques, followed by a discussion of the approaches and likely challenges to integrating sensors into a comprehensive and useful system.


So are we looking at Sensors just because those are cool things? No I do not think so Sensors do have wide applicability and it is more than the cool factor - sensors are likely to cause paradigm shift. There is small use of Sensors but what I think will happened is much bigger acceptance in the usage sensors.

Traditionally sensors have been used in museums to measure the ambient conditions such as light and humidity for preservation purposes. The digital IC based sensors of today provide data that can be monitored remotely with an automated system configured to respond appropriately. The automated system can also log data to help in planning and maintenance.

Sensors: What are they?

Miniature devices that capture sensory data

React to external stimuli

Sensory data incl. heat, humidity, light....

Micro Electro-Mechanical Systems (MEMS)

Data transmission is wireless, whereas the Sensing mechanism and power supply are not

Sensor: Structure

Physical

Transducer + Control Logic

(Analog + Digital)

Abstract

Part of a bigger network

Sensors are much more accurate beyond; often beyond human levels of cognition huge mtbf unlike human...

Sensors: What are they all about?

Captures sensory data from real physical world

Detecting relevant quantities of the data

Monitoring and collecting the data

Assessing and evaluating collected data

Formulating meaningful information

To be conveyed to the user

To be stored for future

Performing decision making

Sensory data comes from multiple sensors of different modalities/requirements often in distributed locations

It is a pipeline one stage after the other

Sensors: Why Museums?

Traditional Uses

User interaction

Exhibit Design

Ubiquitous Computing

Where technology recedes into the background of our lives. - Mark Weiser

TetherlessExperiencePlanned Activity

Sensing CapabilityWow!Sensors provide

Physically unobtrusive, low power, form factor, low maintenance

New sensing paradigms

Combining Sensors with traditional computing systems hand held, PDA, Computer systems can enhance and extend the fun in learning.Smart environments instrumented with sensor-and-wireless-enhanced objects would be able to sense events and conditions about people/objects (basically the participants) and act upon the sensed information or use it as context when responding to queries and commands.

What you see here is sensing + wireless communication + embedded processingUbiquitous Computing term coined by mark Weiser he identified it as the thirdwave in Computing

Sensors: Outlining a Framework

Exhibit

Remote ExhibitBack Office ObserverLink / AgentSensor Net

Sensor FusionSensor Managementdb Management...

ServicesIn here the sensor talks to a Link / Agent it is also conceivable that Sensor Net elements can be designed/implemented in such a way that the data from one sensor will hop to the adjacent sensor until the data reaches the main LAN.

Sensor: Ecosystem Players

Multiple devices per square meter

Mixed data rate requirements

Varying streaming requirements

Real-time and tolerate latency

Databases

Static Database Content, Plan & Rules

Dynamic Database User activity context, Sensor data

Applications

Visitors

SensorsMiddlewareServicesApplicationsDatabase

Sensors: Sense Element

Transducer

Physical property to be sensed

Detectable signal

Source: Springer.com Author: J FortinMeasurand- A physical quantity, property, or condition which is measured. A transducer is a device that converts one type of energy to another. Can either be a Sensor or Actuator. Sensor detect energy in one form and report in another form. Such as Pressure, Temperature, Airbag,...Actuator receives energy and generates action such as loudspeaker, electric motor, .. (electromechanical output devices are generically called actuators)For high precision Capacitive sensors and longer range laser or optical based sensorsEddy-Current sensor tolerance of dirty environment also used for position measurement/sensing as in the disk drives

Sensors: Typical Sensor

Source: Springer.com Author: J FortinSense Element

Physical Property such as heat, light

Signal (Charge current)

Electric current depending on the context, a flow of electric charge (a phenomenon) or the rate of flow of electric charge (a quantity).

Pressure Sensor

Sensors: Transducer Details

Source: Silicondesigns.com

Sensors: SMART Sensor

Provides extra functions beyond just the correct representation of the sensed physical quantity

Moving the intelligence closer to the point of measurement

Control LogicVirtual SensorSense Element(MEMS)ApplicationAlgorithmCommunication InterfaceAnalog-to-Digital Conversion

Signal Conditioning

Digital Signal ProcessingUser Interfacebuttons/ledStorage(Threshold / Calibration)

Physical

InputBase StationHost

SMART SensorS.M.A.R.T.

Self-

Monitoring, Analysis, and Reporting Technology

SMART

Sensors: Virtual Sensor

Virtual Sensor

Source: sparkfun.comControl LogicVirtual SensorSensor ElementApplicationAlgorithmCommunication InterfaceAnalog-to-Digital Conversion

Signal Conditioning


Base StationHost

Smart Sensor

Virtual sensor estimates the properties in conjunction with physical sensors. Virtual sensors manage drifts, calibration

Sensors: Wireless Connectivity

Source: laboratoryequipment.comMost wireless sensors, particularly those based on IEEE 802.15.4 or 900 MHz radios, are designed to use power very conservatively.900MHz can propagate further (less attenuation), whereas 2.4GHz based protocols handle obstruction better (900MHz ISM in NA, Aus. & Israel)802.15.4 standardizes the MAC and PHY the upper stacks (as in WirelessHART and ZigBee) are not compatible. (PHY 868MHz in Europe + 900Mhz elsewhere + 2.4GHz)Wireless Sensors the required data rate, low energy consumption and low cost are paramountWi-Fi/802.11 Security, QoS and Bandwidth are important

Sensors: Power & Networking

Source: laboratoryequipment.com

Source: techbriefs.comIn a cluster tree network, each node connects to a node higher in the tree until the data reaches the gateway. This simple algorithm may be used with any wireless radio technology. Finally, in a mesh network, nodes can connect to multiple other nodes in the system and pass data through the most reliable path available. If one link goes down, affected nodes can pass data through another path to reach the gateway. Most IEEE 802.15.4-based devices employ some type of mesh network topology, because of this self-healing effect.In Star all sensors transmit directly to the central data collection point. Mesh network best over large distances, harsh RF environments, to avoid 1 single point of failure

Sensors: Key Drivers

Improving Cost & Yield

Standardization efforts in Wireless Networking

Cheaper Efficient Tinier Processing Logic

Quick Integration Methods

Development of low power radio technologies

Advances in low-power embedded micro-controllers

Advances in the computing technology promotes the sensing and act on the physical environment suggesting the person to physical world connection is closer and achievable than ever.

Sensors: System Design

Wireless Networking

Middleware Services

Data Management

Sensory User Interaction (SUI)

Approach

Identify the use case scenarios

List sense element and energy domain details

Calculate anticipated workload

Identify the sensor network algorithms

Perform the Sensor System Design in conjunction with the Exhibit Design

Having sensors and wireless connectivity is only the first part of the puzzle the widdleware services is essential for a successful SUI

Sensor: Identifying a Sensor

Identify the measurand

Energy Domain

Usage Pattern

Bandwidth and other resource requirements

Characteristics

Power consumption

Network support

Form factor

Volume of sensors to deploy and use

Vendor selection

Minimum Quantity requirements

Lead time

Sensors: Technology restrictions

Size and packaging

Energy efficiency (Power constraints)

Data rates for the wireless data transfer

High data rates (Audio/Video) / Streaming

Low data rates (spatial sensors, environment sensing)

Fine grained estimation and tracking of location and orientation of large number of objects that are being sensed

Quality of Service needs

QoS - it maybe OK to miss temperature samples but not necessarily that of the orientation sensor

Sensors: System Example

Sensors - Lightweight

Location & Orientation

Identification

Network Agent Conduit for the sensors

Master Act upon sensor data

Location & OrientationIdentificationObject TrackingSpatial Configuration of multiple users and objects

Generate information such a Kid A is in the corner near Pyramid A

AgentHost Sensors: Outlining a Framework

Sensor 1Sensor 2Sensor 3ComputerWeb

Exploration & Learning PlanContent ManagementExploration & Learning Interaction HandheldSystem HardwareSoftware App stackSensors

ELP manages the purpose of the tool or the exhibit ...such as (i) Weather Station it will be weather science study that is adjusted to the age group (ii) Earth navigator it will be region & climate study lCM Manage local data, share if necessary data with similar systems (Database Mgmt)ELI It handles the UI and rules management To summarize the three key challenges are to be handled are- creating networked sensing approaches- networking protocols optimized for large scale and high density sensor presence- processing and analysis of data generated by all these sensors

Sensors are a mature market!

Using those sensors in a large scale, in Museums, will have a revolutionary effect in user experience.

Sensory User Interaction is here to stay!

If there is sufficient interest we can explore opening a SIG under MCN

To receive these slides, please send an email to [email protected]

Sensor: Getting Engaged!

Thank you!

Backup

Sensors: Experience Realms

Sensors can enhance the all experience realms

Sensor: Sample applications

Wireless network of toys

Learning individualized to the participant / each child

Unobtrusive evaluation of the learning process

Hidden in the infrastructure (walls, chairs, ...)

Music toys (MIT Media Lab's Toy Symphony)

Heavy on gestures and tactile in nature

Embed sensors for touch, pressure .. in toys and exhibit objects and detect their manipulation

Ubiquitous Computing "that which informs but doesn't demand our focus or attention."Problem solving in nature unstructured because of the kind of data that is collected to make sense out of it. And then react to it in realtime in a context sensitive fashionToys of Tomorrow and Music Toys programs at MIT's Media Lab

Sensors: Compare to a typical Computing System

Ad-hoc and Distributed structure

Likely to be large scale yet sparse in density

Unreliability due to nature of the link

Restricted system resources, Power management

Overcome by huge amount data that gets collected (redundancy)

Physical stimulus and reactionary in nature

Predominantly unstructured and asynchronous

Diversity of data types with large dynamic range of rate, latency, processing requirements

Sensors: Transducer Properties

Physical Properties

Used to measure Pressure, temperature, Humidity...

Motion Properties

Used to measure Acceleration, Position, Angular velocity, Direction

Contact Properties

Used to measure Vibration, Slip, Strain

Presence

Used to measure Tactile, Contact, Proximity, Motion, Light

Identification

Used to measure ID Data, Retinal, Voice, ...

Sensors: Sense Element Basics

Source: lionprecision.com

Source: analog.comSource: eetimes.com

For high precision Capacitive sensors and longer range laser or optical based sensorsEddy-Current sensor tolerance of dirty environment also used for position measurement/sensing as in the disk drivesSecurity aspects are key to while designing proximity sensors.Hall effect is another type of electromagnetic sensor - production of a voltage in a current-carrying semiconductor in the presence of a magnetic field.Thermocouples based on Seebeck effect.Resonant-Temperature sensor based on the property of SiO2 to exhibit a change in resonant frequency depending on temperature change.Optical transducers can be optimized for different frequencies of light visible and non-visible so that you can have infrared detectors, ultraviolet detectors and so on.

Sensors: Other Sensor Elements

Source: sandia.gov

Source: sensormag.comChemical Transducers used in environmental monitoringChemiresistors are expensive because of the specialized nature nevertheless it is very accurate. It uses electrodes that are coated with specialized chemical agents that change their resistance when exposed to certain challenge agents.Array of biosensors are put together for an Electronic nose.Em Spectrum sensors used in autonomous vehicle navigation. It requires expensive DSP techniques including edge detection, segmentation, motion analysis etc.,Acoustic sensors also uses Doppler techniques for the measurement of velocitiesAcoustic Wave Sensors uses the changes to the characteristic of the propagation path effect the velocity and/or amplitude of of the acoustic wave these sensors are often used in conjunction with materials that demonstrate Piezoelectric effect. It I perhaps the most versatile of sensors because it has been used to sense many physical properties

Sensors: Mapping a Smart Sensor

Control LogicVirtual SensorSensor ElementApplicationAlgorithmCommunication InterfaceAnalog-to-Digital Conversion

Signal Conditioning


Base StationHost

Smart Sensor

Sensors: MEMS Sensor SoC

Control LogicVirtual SensorSensor ElementApplicationAlgorithmCommunication InterfaceAnalog-to-Digital Conversion

Signal Conditioning


Base StationHost

Smart Sensor

Source: invensense.com

Sensors: Form factor

Standalone

Integrated onto a PCB

Source: monnit.com

Source: kcftech.com

Source: freescale.com

Sensors: Adoption Today

Building industry, Green evolution, Transportation, Home automation, ...

Importance indicated by IEEE driven standards in this space

Driven by affordability and ease of use

Efficient and low cost connectivity methods

Classified solutions based on data rates

Predominantly used as spatially distributed autonomous sensors to monitor physical environment conditions.

Backup

Sensor: Challenges

Power

Lack of ruggedness

Steep learning curve

Actuator: Display Technology

Source: flexlighing.com

Source: holografika.com

Source: microvision.com

Source: mirasoldisplays.comSensors when coupled with the growth in display technologies and tactile feedback technologies will open a wavefront of innovation in user interaction and exhibit design.

Actuator: Tactile Feedback

Source: densitron.com

Source: densitron.comSource: immersion.com

When the user touches the screen, a position signal is sent to the microprocessor. The host application interprets this position and commands the lightweight TouchSense player, embedded on the processor, to play a specified tactile effect, such as the perception of a button press.Haptics is a catchall term for sub-types including Tactile (the sense of pressure applied through skin), kinaestehtic (motion of the body),

Actuator and Sensor Combined: Touchable 3D Display

Source: docomo

References

Weiser, Mark The Computer for the 21st Century Scientific American Vol 265 p 66-75

http://www.ubiq.com/hypertext/weiser/SciAmDraft3.html

Smart Kindergarten: Sensor-based Wireless networks for Smart Developmental Problem-solving environments - ACM ISBN 1-58113-422-3/01/07

thepaca.net

Transducer typeInput (Property of Interest for Sensor)Output (Property of Interest for Actuator)Also known asSensorAcceleration measuredDigital representation (along the axes)AccelerometerSensorPressure measuredVoltage outputPressure sensorActuatorDigital SignalVoiceLoudspeakerActuatorDigital SignalRotary MotionElectrical Motor

???Page ??? (???)10/30/2010, 10:42:26Page / Energy DomainMeasurandSense PrinciplePhysical PropertiesPressurePiezoresistive, CapacitiveTemperatureThermistor, Thermo-mechanicalHumidityResistive, capacitiveMotion PropertiesPositionElectro-Magnetic, Contact SensorAccelerationVibration (Proof-Mass), CapacitiveGyroscopeCapacitive, Electro-MagenticContactStrainPiezoresistiveVibrationPiezoresistive, SoundPresenceTactile/ContactContact, capacitiveProximityHall effect, Magnetic, RFIdentificationID Fingerprint, data stored, retinal scan

???Page ??? (???)10/30/2010, 10:42:26Page / DriversToday's sensor future

ScaleMicroNano

Power consumptionlong life (> 2 years)energy harvesting

???Page ??? (???)10/30/2010, 10:42:26Page / Energy DomainCharacteristicTransduction PrincipleMechanicalRely on direct Physical contactCapacitive Sensors as in Touch Sensors Piezoelectric effect as in balls that lit when bounced Electromagnetic / Magnetic Useful for detecting proximity eventsEddy-current sensors allows bigger sensing range and bigger probe spot size RFID use power in the interrogating signals to send back small amounts of dataThermalMeasure temperature or heat fluxThermoresistive effect exploits resistance of a conductor/semiconductor changes with temperature Thermocouples sensor based on current flows between two materials are joined together and one is hotter than the other. It is less expensive and is very reliable Resonant Temperature sensors are expensive and very high accuracy.Opticalconvert light to various quantitiesPhotoelectric effect measures the flow of electrons based on incident light

???Page ??? (???)10/30/2010, 10:42:26Page / Energy DomainDescription / Uses

Chemical Interact with matter of all types Used in sensing pollutions causing gases

BiologicalMedical Diagnostic, detecting Pesticides

ChemiresistorsImplemented with an array of chemical sensors, interpreted using a pattern-recognition algorithm to sense a variety of chemicals. Used in Contamination assessment

Metal-Oxide Gas sensorsrelies on adsoprtion of gases onto certain semiconductors changes their resistivity. Used in smoke detectors

BiosensorsSensing depends upon selectivity of biomolecular reactions such as molecular binding sites detect property changes mass, resistance, spectral reading

EM spectrumRadar / Lidar, GPS

Acoustic Sound as the sensing medium detecting fluid leakages and earthquakes

Acoustic WaveEmploys two sets of fingers one to generate the surface Acoustic Wave and the other to detect the changes. Very versatile in its applications.

???Page ??? (???)10/30/2010, 10:42:26Page /