The Hitchhiker’s Guide to
Successful Residential Sensing
Deployments
Timothy W. Hnat, Vijay Shrinivasan,
Jiakang Lu, Tamim I. Sookoor, Raymond
Dawson, John Stankovic, and
Kamin Whitehouse
1
Sensing in Homes
Medical
Monitoring
Home
Automation
Energy
Management
People spend 65% of time in their homes
2
Sensing in Homes
Extreme Environments
Indoors is hard too!
Photo courtesy of: Jan Beutel
3
Sensing in Homes
Difficulty
 1200 sensors
 Over 20 homes
 Up to 1 year/home
#Sensors
4
Sensing in Homes
Difficulty
 1200 sensors
 Over 20 homes
 Up to 1 year/home
#Sensors
#Homes
5
Sensing in Homes
Difficulty
 1200 sensors
 Over 20 homes
 Up to 1 year/home
#Sensors
#Homes
#Days
6
Outline
 Deployment Overview
 Reliability and Failure Analysis
 A Hitchhiker’s Guide
7
Deployments Overview
8
Deployments Overview
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Deployments Overview
10
Deployment
# Homes
Weeks
Motion
Object Use
Door Heights
Wearable
Tracking
Light Switch
Power (Plugs)
Power
(Circuits)
Power (Mains)
Water Mains
Custom
Thermostat
Active Register
Light/Temp
Humidity
Our Deployments
A
11
1-2
2530
1220
-
-
-
-
-
-
-
-
-
-
B
1
1
-
-
12
12
-
-
-
-
-
-
-
-
C
3
3-4
1525
-
-
-
-
-
-
-
-
-
-
1225
D
1
2
4
-
-
-
-
2
-
-
-
-
-
-
E
1
2
5
-
-
-
-
-
1
-
-
-
-
-
F
1
28
65
13
13
16
22
-
-
1
1
1
12
86
G
1
44
54
7
31
14
22
8
37
1
1
1
12
29
H
1
39
15
7
14
-
11
4
-
1
1
-
-
-
I
1
32
25
10
30
-
31
3
48
1
1
-
-
8
J
1
25
14
5
17
-
7
2
-
1
1
-
-
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Outline
 Deployment Overview
 Reliability and Failure Analysis
 A Hitchhiker’s Guide
12
Sensors
Fault Analysis
…
Time
13
Failure Analysis
Internet
Central Database
Thermostat
Relay Machine
…
…
Temperature Sensors
Light Switches
Doorway Sensors
14
Power Outage
Sensors
Fault Analysis
…
Time
Sensor-Days – down time × number of sensors
15
Fault Analysis
Reinstall
Hard drive failure
Plug disconnections
Sub-system failure
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Outline
 Deployment Overview
 Reliability and Failure Analysis
 A Hitchhiker’s Guide
17
Homes are Not a Power Panacea
 30-40 outlets per house
 Long wires
 2.3x more down time than
batteries
 More maintenance calls
18
Homes Have Poor Connectivity
 Wireless connectivity
 Power line communications
 Wires
 180bit/s
 5 min polling rate
Exploiting Home Automation Protocols
for Load Monitoring in Smart Buildings
19
Homes are Hazardous Environments




Children
Mobile objects
Roomba
Guests and
cleaning services
20
Homes are Remote Environments
 Minimize installation time
 Scout
 Lab assembly and
configuration
 Checklists
21
Expect Limited User Participation




Button Tracking
Wearable Tracking
Self-reporting
Surveys
22
Aesthetics Matter in Homes
 Disappear into the
woodwork
 Leave no trace
 No LEDS at night
 Noise
23
Simplify the Architecture
Internet
Central Database
Thermostat
Relay Machine
…
…
Temperature Sensors
Light Switches
Doorway Sensors
24
Similar Work
 Infrastructure-based
 Neural Network House, Aware-Home, MavHome,
PlaceLab
 Infrastructure-less
 Tapia, Cook, Kasteren
 Lessons Learned
 Edwards and Grinter – 7 challenges
 “Hitchhiker’s guides for WSN deployments”
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Summary







AC Power is not abundant or reliable
Wireless connectivity is worse than expected
Unexpected environmental hazards
Houses are remote environments
User participation is limited
Aesthetics are important
COTS are a double-edged sword
26
Thank You
Any questions?
27
Root Failures
Root Cause
House G
House H
House I
House J
Sensing sub-system
4107
642
4757
274
Gateway Down
5596
0
3
136
Plug Disconnected
509
30
474
10
Battery Dead
452
17
168
0
Wireless Link Loss
410
0
122
1
Internet Down
251
97
178
9
Power Outage
21
0
87
2
28