New Devices

1
New Devices

• Jonathan Hui
• jwhui_at_cs.berkeley.edu
• Computer Science Division
• University of California, Berkeley

2
Outline

• Telos Experimentation Kit
• Wall-plug Mote
• Impact on Services
• Enabling New Applications

3
Telos Experimentation Kit

• Device for sensor experimentation and
  classroom/laboratory use of wireless sensor
  networks
• Consists of
• Telos Revision B
• Telos Sensor Board
• Battery and Charger

4
Telos Sensor BoardPolastre and Dutta

• Microphone
• Sampling up to 200ksamples/second
• Analog compander eliminates noises and amplifies
  signal, low pass filter, configurable compression
  and noise gate
• Wakeup microphone energy caught by low pass
  filter with decay, interrupt set by mic energy
  threshold
• Speaker
• 700mW output to 8 ohm speaker
• Output to DAC up to 200,000 times/second
• Accelerometer
• ADXL320 low power /-5g
• Configurable window comparator
• Detects light taps to heavy shaking
• Light sensor
• Photodiode with current amplifier
• Configurable gain for low level ambient indoor
  light to high level direct sunlight

5
Telos Sensor BoardPolastre and Dutta

• Principles
• Low Power operation
• Sensors operate down to 2.2V
• Low active and standby current consumption
• Sub-circuit isolation
• Wakeup circuitry
• Event detection
• Interrupts
• High performance
• Up to 200ksamples/sec 12-bit ADC with reference
  voltages
• 12-bit DAC, interrupts with Timer capturing
• Configurable
• Set thresholds, gain, and triggering

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Power SubsystemPolastre

• Telos USB/Li Charger
• Charges Li battery when connected to USB
• Indictor LED
• Red charging
• Green fully charged

7
How it all fits together

• Telos in enclosure
• Key metaphor using USB connector
• Telos, Sensor Board, Charger, and Battery
• Cradle holds Telos device

• Applications
• Ubiquitous Computing
• Keychain device
• Sensors as UI input
• Classrooms/Labs
• Digital Signal Processing
• Wireless Networking
• Embedded Systems
• Sensing and Control
• Etc

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Wall-Plug Mote

• Mote-controlled, AC wall-plug
• Functions
• Energy metering of AC devices
• Actuation (relay and dimmer)
• Wireless network relay
• Control todays AC appliances

• People
• (EECS) David Culler, Jonathan Hui, Joe Polastre,
  Xin Yang
• (MechE) Paul Wright, Charlie Huizenga, Alex Do

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Wall-Plug Device

• Processor/radio
• Telos rev. B
• Additional MSP430 coprocessor to offload
  computation if needed
• Energy meter IC
• Voltage RMS
• Current RMS
• Total energy consumed
• Threshold for surge and SAG detection
• Digital calibration
• Power Relay
• Up to 16 amps
• Double latching
• Dimmer with Triac
• Up to 6 amps
• Default to off position

Front View
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Wall-Plug Device

• User feedback / debugging
• Four external LEDs
• Alpha-numeric, backlit LCD display
• User Button
• Tap to change display mode
• Hold down to reset energy meter accumulator
• Power/Reset Button
• RFID tag for identification
• Transformerless AC-DC converter
• Less than 600 mW ambient power dissipation

Front View
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Wall-Plug Design Issues
Rear View

• Still requires some physical inputs
• USB for Telos
• Physical switch to set relay or dimmer
• Output for energy-meter calibration
• Panel on rear exposes these features
• Forcing user to unplug box removes possibility
  of
• Connected USB while on AC power
• Accidentally switching box between dimmer and
  relay mode

12
Wall-Plug Design Issues
Telos
Low-voltage board

• 4-board design
• High-voltage board, Low-voltage board, Telos, UI
  board
• Protect DC components from high voltages
• Removable UI board for thinner version without UI
• For plugs behind large appliances

UI Board
High-voltage board
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Wall-Plug Design Issues
Telos

• Positioning
• Telos on top
• AC circuitry on bottom
• Structural design
• Robust to many insertions and removals from
  outlet
• Packaging specially designed to press-fit boards
  for strength
• Heat Dissipation
• Might be an issue Dimmer outputs 1 Watt/Amp
• May require vents in the package
• Moisture / Seal from environment
• Only to protect user from high-voltage
• Not subject to outdoor use

14
New Deployments

• Previous Deployments
• Environmental Monitoring
• Great Duck Island
• Redwood Forests
• Golden Gate Bridge
• Indoor environment at Intel
• Military Applications
• Vehicle tracking and unmanned pursuit
• Event detection and classification

• Future Deployments
• Household Applications
• Nearly any AC-powered item (space heaters,
  dish-washers, refrigerators, etc.)
• Lighting / Climate control
• Anomaly detection
• Medical monitoring
• ... many other household applications

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New Deployments

• Environmental Monitoring
• Military Applications
• Energy constrained
• Sparse node density causes radio coverage problem
• Packaging for outdoor deployments and unattended
  use

• Household Deployments
• with AC-powered motes
• No energy constraints
• Will want to control many household appliances,
  so radio coverage is given
• Packaging for indoor deployments and occasional
  physical interaction
• Utilize Telos Experimentation Kit to provide
  sensing information

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New Network Topology

• Heterogeneous networks in terms of energy
• AC-powered
• Battery-powered

BAT
BAT
AC
BAT
AC
AC
AC
BAT
BAT
BAT
AC
BAT
BAT
AC
BAT
AC
AC
BAT
BAT
AC
BAT
BAT
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Impact on Services

• Time synchronization
• Low power listening
• Routing
• Dissemination
• Deployment Localization
• Mobility

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Time Synchronization

• Dimmer requires synchronization with AC wave

• AC signal provides a global clock signal
• Fine-grained time-sync much easier when using AC
  signal

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Low Power Listening (LPL)
TX

• LPL without time sync incurs high transmit and
  receive costs

packet
RX
wakeup
wakeup
wakeup
packet
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Routing

• Routing infrastructure maintained using AC nodes
• AC nodes provide communication backbone
• Leaf nodes dont have to relay packets
• Backbone nodes to communicate with little
  overhead
• Radio coverage due to numerous devices we wish to
  control

BAT
BAT
AC
BAT
AC
AC
AC
BAT
BAT
BAT
AC
BAT
BAT
AC
BAT
AC
AC
BAT
BAT
AC
BAT
BAT
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Dissemination

• Backbone allows for quick dissemination
  throughout network
• Battery nodes only wake up to receive, not
  transmit

BAT
BAT
AC
BAT
AC
AC
AC
BAT
BAT
BAT
AC
BAT
BAT
AC
BAT
AC
AC
BAT
BAT
AC
BAT
BAT
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Deployment Localization

• No extra wires required!
• Use RFIDs on outlet, wall-plug device, and
  appliance for quick deployment
• Associate mote with outlet gives location
• Associate mote with appliance gives information
  of what is being controlled
• Download applet for specific appliance

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Mobility

• Mobility model
• AC-powered nodes are static
• Battery-powered nodes may be mobile
• Dealing with mobility is simpler
• Effective low-power listening with global
  time-sync
• Transmit/receive messages to/from nearest AC node
• Approximate location determined by radio
  connectivity

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New Applications

• AC-powered mesh network infrastructure simplifies
  many problems
• Time synchronization
• Low power listening
• Routing
• Dissemination
• Deployment Localization
• Mobility
• Enables us to think of new applications

25
Applications Lighting Control

• Maintain light-level with users preference in a
  room with windows and sun-light
• While minimizing electrical costs
• Sensors
• Battery-powered nodes with photo sensor
• Actuators
• Wall-plug dimmer

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Applications Climate Control

• Maintain temperature with users preference
• While minimizing electrical costs
• Sensors
• Indoor temperature, Outdoor temperature, Energy
  cost
• Actuators
• Ceiling fans, air-conditioner, heater, window
  blinds
• Large time constants in control allow pre-cooling
• pre-cool when energy is cheaper
• Also applies to refrigerators, water-heater, etc.

27
Applications Demand-Response

• Electric utility provides real-time energy prices
• Customers adjust usage of appliances and other
  items based on current energy price
• Customers reduce costs by adjusting when and how
  long to operate electrical items
• Load shedding during high demand prices can
  reduce peak electrical load on utility

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Applications Demand-Response
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Applications Anomaly Detection

• Light bulb burn-out detection
• Appliance health monitoring
• By measuring energy consumption characteristics
• Detect inefficiencies of air-conditioner
• Sensors indoor outdoor temperature sensor,
  energy meter for AC
• Detect when window is open, filters are clogged,
  etc.
• Micro-electric monitoring for many other problems
• Electrical and non-electrical
• High energy usage by water pump due to water leak

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Applications Medical Devices

• With communication backbone, plug in new devices
  to create a new application
• Home health monitoring
• Pulse oximeter
• Wireless EKG
• Accelerometer
• Glucose meter
• Home security
• Entertainment
• your application here

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Closing the Loop

• Closing the loop in non-military applications
• Differences from PEG
• Both large and small time constants (temperature,
  light)
• Integrate multiple sensors
• Energy meter, temperature, light, sound,
  accelerometer, etc.
• To control
• Ceiling fans, air-conditioner, lighting, any AC
  appliance
• Multiple user preferences
• A technology that consumers can immediately
  appreciate

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Conclusion

• New devices are not novel
• we know how to build them
• but they enable new application thinking
• Other than environmental monitoring military
• Make sure services we develop are enough to cover
  these
• AC Wall-Plug and Telos Experimentation Kit may
  help drive adoption of sensor networks
• AC-powered infrastructure (just plug it in)
• Simplifies many services
• Applications that consumers can appreciate

33
Energy-Meter Relay

• Developed by Xin Yang
• Mica2-dot for wireless communication and
  computation
• Energy meter IC
• Power relay for actuation

34
Energy-Meter Relay

• Integrated with Oscilloscope (demo tonight)

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Applications Demand-Response

• When electrical utility rate changes control
  system can automatically adjust
• Light dimmers
• Climate-control (air-conditioning/heating)
• Ceiling fans vs. air-conditioner
• Water heater and other appliances
• Outdoor pool equipment
• etc.
• Control system can also give user feedback
• Current total energy consumption of household
• Current electrical utility rate
• Feedback allows the user to determine when to use
  energy intensive appliances (i.e. washer/dryer).

36
Power Management

• AC nodes can make intelligent decisions for
  battery-powered nodes
• Battery-powered nodes provide data about
  environment around AC node
• AC node can ask surrounding nodes to increase
  duty cycle if event is interesting