Smoke: Mote Powered Fire Evacuation

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Smoke Mote Powered Fire Evacuation

• Manan Gosalia, Kaisen Lin, Andrew Redfern, Slava
  Romanovsky, Nikita Shah, Dan Steingart, Shi-Hua
  Teh, Neil Turner, William Watts, Xin Yang, and
  Philip Levis
• CS199 Sensor Network Systems, Fall 2004

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Saving Lives in Fire Rescue

• Part of the CITRIS Project
• Interviews with Chicago and Berkeley Fire
  Departments defined five needs
• Fire fighter HUDs
• Captain information displays
• Evacuation guides
• Building health
• Victim localization

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Saving Lives in Fire Rescue

• Part of the CITRIS Project
• Interviews with Chicago and Berkeley Fire
  Departments defined five needs
• Fire fighter HUDs
• Captain information displays
• Evacuation guides
• Building health
• Victim localization

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Intelligent Evacuation Guides

• Network can have dense danger data
• Guide occupants along shortest safe paths

4th Floor Soda Hall
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Intelligent Evacuation Guides

• Network can have dense danger data
• Guide occupants along shortest safe paths

4th Floor Soda Hall
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Intelligent Evacuation Guides

• Network can have dense danger data
• Guide occupants along shortest safe paths

4th Floor Soda Hall
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Building Health

• Building health needed to compute paths
• Fire, carbon monoxide, impassable, etc.
• Network health needed for maintenance
• Low batteries, node failure, etc.
• Mote network should provide both
• Operation in the presence of failure

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Smoke

• Mote (TinyOS) application
• Monitor and report building environment
• Detect danger conditions (e.g., smoke)
• Illuminate shortest safe escape paths
• Provides script interpreter for management
• Java tools
• Configure, reset, and visualize network state
• Generate and inject scripts into network
• Demonsrated operation on 12/21/04

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Outline

• Introduction
• Smoke TinyOS Application
• Smoke Administrator Tool
• Future Work and Conclusion

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Outline

• Introduction
• Smoke TinyOS Application
• Smoke Administrator Tool
• Future Work and Conclusion

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Smoke Mote Requirements

• Normal operation
• Report misconfigurations, failures, low batteries
• Detect danger and transition to danger state
• Danger state
• Report building state (temperature, etc.)
• Illuminate shortest safe escape paths
• Be robust to node failure, loss, and noise
• Accept uncertainty fail safe, and fail soft

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Smoke TinyOS Hardware

• Mica2 motes (433 MHz)
• Smoke detector sensors
• Custom sensor board two traffic lights
• Red, yellow, and green

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High Level Behavior

• Report state at a low rate
• Ad-hoc collection routing to base station
• Mote enters fire state, floods an alarm
• Motes go to danger state, increase report rate
• Marked exit nodes advertise they are exits
• Compute shortest safe path to an exit
• Shortest means by hopcount
• Safe means not through a mote in fire state
• Signal direction of safe path

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Computing Safest Path

• Motes need to be aware of direction
• Distinction between network and physical
  neighbors
• Network implies connectivity
• Physical defined by hallways, etc.
• Computing path involves selecting physical
  neighbor that is closest to an exit

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Physical Neighbors

• Establish physical paths in network
• Up to two hops away
• Two directions (East/South or West/North)
• Correspond to two traffic directions
• Configured at deployment time
• (PARC work suitable here)
• Motes monitor connectivity (snooping)

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Physical Path Examples
B
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Physical Path Examples
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Physical Path Examples
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Physical Path Examples
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Physical Path Examples
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Computing the Path

• Exit motes (if not on fire) have distance zero
• Motes on fire advertise large distance F
• If mote distance gt F, no safe path
• Motes cache physical neighbor state
• Snoop on status updates
• Illuminate path to shortest neighbor
• Fire are both red, exits both green
• Always prefer single hop neighbors

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Dealing With Uncertainty

• What if a neighbor stops reporting?
• Dont know its state it could be on fire!
• Neighbors time out to be AWOL
• Known paths are better than AWOL paths
• If only an AWOL path remains, show yellow lights
  (uncertain)
• People must make decisions on own (as before)
• Report distance large distance A (ltlt F)

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Example Soda Hall
Exit
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Example Soda Hall
Exit
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Example Soda Hall
Exit
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Example Soda Hall
Exit
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Example Soda Hall
Exit
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Example Soda Hall
Exit
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Example Soda Hall
Exit
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Example Soda Hall
Exit
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Example Soda Hall
Exit
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Smoke TinyOS Software
Health
Path
Alarm
Local State
Neighborhood
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State Management

• Keep track of local and neighbor state
• Signal stateChanged event when needed

Health
Path
Alarm
Local State
Neighborhood
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Health Monitoring

• Periodically report mote state (collection)
• If fire detected, change mote into fire state

Health
Path
Alarm
Local State
Neighborhood
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Alarm Dissemination

• Listen for local state change events
• If mote enters fire state, flood alarm

Health
Path
Alarm
Local State
Neighborhood
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Escape Path

• Only active in danger state
• Compute shortest safe path, actuate lights

Health
Path
Alarm
Local State
Neighborhood
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Scripting Support

• Scripting interface to configure motes

Maté VM
Health
Path
Alarm
Local State
Neighborhood
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Example Script Uses

• Test hardware (stoplights)
• Loose connections, short outs, etc.
• Start/reset network
• Configure neighbors
• Faking a fire

• stopsys()
• clear_state()
• sleep(5 rand()5)
• bootsys()
• Simple network reset

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Example Script Uses

• Test hardware (stoplights)
• Loose connections, short outs, etc.
• Start/reset network
• Configure neighbors
• Faking a fire

• stopsys()
• clear_state()
• clear_neighbors()
• sleep(5 rand()5)
• bootsys()
• If you need to reconfigure the physical topology

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Example Script Uses

• Test hardware (stoplights)
• Loose connections, short outs, etc.
• Start/reset network
• Configure neighbors
• Faking a fire

• stopsys()
• clear_state()
• sleep(5 rand()5)
• bootsys()
• if (id() 5) then
• onfire()
• end if
• If you want to test the networks operation

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Outline

• Introduction
• Smoke TinyOS Application
• Smoke Administrator Tool
• Future Work
• Conclusion

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Administrator Requirements

• Monitoring
• Display network state
• Show failures, low batteries, connection issues
• Configuration
• Use visual interface
• Lay out physical paths
• Generate scripts that configure nodes
• Reset (hard and soft)

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Admin Screenshot
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Outline

• Introduction
• Smoke TinyOS Application
• Smoke Administrator Tool
• Future Work and Conclusion

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Future Work

• Physical path representation
• Notion of better paths not unit distances
• Improved path information edge cases
• Multiple floors, more complex floorplans
• Simple deployment (PARC work)
• Bigger, more visible hardware
• Admin tool simplification (still for devel)
• Permament deployment in Etcheverry
• Demonstration to Berkeley Fire Department

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Conclusion

• Smoke a wireless sensor network for smart fire
  evacuation
• Distributed, in-network algorithms to compute
  safest paths
• Guide people to exits
• Handles node failure and uncertainty
• Fail soft, be explicit about uncertainty
• Congratulations for those who did the real work!