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The Future of Wireless Sensor Networks
Kris Pister
Prof. EECS, UC Berkeley
Co-Director, Berkeley Sensor & Actuator Center
(Founder & CTO, Dust Networks)
Autonomous Microsensor Networks with Optical Communication Links
• PI: Kris Pister
• Source: Hughes (MICRO)
• Funding: $25k, $10k matching, 0% ovhd,
• Duration: 1 year
• Comments: Collaboration w/ Prof. Joe Kahn under separate MICRO
BSAC IAB 1997
COTS DustGOAL:
• Get our feet wet
RESULT:
• Cheap, easy, off-the-shelf RF systems
• Fantastic interest in cheap, easy, RF:– Industry
– Berkeley Wireless Research Center
– Center for the Built Environment (IUCRC)
– PC Enabled Toys (Intel)
• Fantastic RF problems
• Optical proof of concept
BSAC IAB Spring 2000
Berkeley Demos – 2001
Intel Developers Forum, live demo800 motes, 8 level dynamic network,
Seismic testing demo: real-time data acquisition, $200 vs. $5,000 per node
vs.
50 temperature sensors for HVAC deployed in 3 hours. $100 vs. $800 per node.
Motes dropped from UAV, detect vehicles, log and report direction and velocity
Cost of Sensor Networks
Time
$
Computing Power
Sensors
Installation, Connection and Commissioning
Mesh Networking
Source: InStat/MDR 11/2003 (Wireless); Wireless Data Research Group 2003; InStat/MDR 7/2004 (Handsets)
0
100
200
300
400
500
600
700
800
2003 2004 2005 2006 2007
Un
its
(M
illio
ns
)
Wi-Fi nodesHandsetsWireless Sensor Nodes
Sensor Networks Take Off!
$8.1B market for Wireless Sensor Networks in 2007
Industry Analysts Take Off!
Low Data Rate WPAN Applications
RESIDENTIAL/LIGHT
COMMERCIAL CONTROL
CONSUMER ELECTRONICS
TVVCRDVD/CDremote
securityHVAClighting controlaccess controllawn & garden irrigation
PC & PERIPHERALS
BUILDING AUTOMATION
securityHVAC
AMRlighting controlaccess control
mousekeyboardjoystick
PERSONAL HEALTH CARE
patient monitoring
fitness monitoring
INDUSTRIALCONTROL
asset mgtprocess control
environmentalenergy mgt
Zigbee 2003Zigbee 2006Zigbee Pro
Barriers to Adoption
0% 20% 40% 60% 80% 100%
Reliability
Standards
Ease of Use
Power consumption
Development cycles
Node sizeOnWorld, 2005
Dust Networks
• Founded July 2002
• Focused on reliability, power consumption
• Developed TSMP– Time Synchronized Mesh Protocol– >99.9% reliability– Lowest power per delivered packet
Oil Refinery – Double Coker Unit
• Scope limited to Coker facility and support units spanning over 1200ft
• No repeaters were needed to ensure connectivity
• Electrical/Mechanical contractor installed per wired practices
• >5 year life on C-cell
GW
400m
The De-facto Standard
Emerson
Siemens
Pepperl+Fuchs
ABB
Endress+Hauser
Honeywell
MACTek
PhoenixContact
Smar
Yokogawa
Siemens
Elpro
12 Manufacturers,1 Network – Dust Networks’ TSMP
Federspiel Controls
HVAC System Retrofits
Demonstrated Energy Savings:
• 3.7 kWh/sf/yr
• 0.34 therms/sf/yr
• Higher savings than conventional retrofits
Barriers to Adoption
0% 20% 40% 60% 80% 100%
Reliability
Standards
Ease of Use
Power consumption
Development cycles
Node sizeOnWorld, 2005
>99.9%
Wireless HART, SP100
“It just worked”
5-10 years
Complete networks
2.4 GHz Transceiver Front End
• Cook et al., ISSCC 2006
• Active Area: 0.8mm2 • Zero external RF
components
Radio Performance
200k Bit rate (bps)100k 300k
I RX (
mA
)
5
10
20
15
25
X cc1000
Molnar 04 (0.4mA)
X
X cc2420
XOtis 05 (0.4mA)
Cook 06 (300 W)
X
With software:10 years D cell
With software:10 years coin cell
RF Time of Flight Ranging in a Coal Mine Tunnel
0 2 4 6 8 10 12 14 16 180
10
20
30
40
50
60
70
Distance (m)
Tim
e of
Flig
ht (n
s)
1 m Error
2 m Error
Ideal
Measured Data
Steven Lanzisera
~2 mm^2 ASIC
Mote on a Chip? (circa 2001)
• Goals:– Standard CMOS– Low power– Minmal external components
uP SRAM
RadioADC
Temp
Ampinductor
crystal
battery
antenna
UCB Hardware Results ~2003
• 2 chips fabbed in 0.25um CMOS– “Mote on a chip” worked, TX only
– 900 MHz transceiver worked
• Records set for low power CMOS– ADC, Mike Scott, M.S.
• 8 bits, 100kS/s
• 2uA@1V
– Microprocessor, Brett Warneke, PhD.• 8 bits, 1MIP
• 10uA@1V
– 900 MHz radio – Al Molnar M.S.• 100kbps, “bits in, bits out”
• 20 m indoors
• 0.4mA @ 3V
~4 mm^2 ASIC
Mote on a Chip, 2009
• Goals:– Standard CMOS– Low power– Minimal external components
uP SRAM
RadioADC
Temp
Ampinductor
crystal
battery
antenna
Security
Location
Time
Zero