The Future of Wireless Sensor Networks

Kris Pister

Prof. EECS, UC Berkeley

Co-Director, Berkeley Sensor & Actuator Center

(Founder & CTO, Dust Networks)

Outline

• The Past

• What Went Wrong

• Technology Status

• Applications

• Technology Directions

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

50 motes, 7 hops3 floors, 150,000sf

>100,000 packets/day

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

Standards

• IEEE 802.15.4• Wireless HART• ISA SP100

Wireless HART booth at ISA Expo, Oct. 2006

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

Excerpts from Customer Presentations at the Emerson Process Users ConferenceOctober 2-5, 2006

Streetline Networks

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

Conclusion

• 10 years later, a real market emerges• Reliable, low power, standards-based

technology is no more expensive than junk

• The lowest power radios in the world come from UCB/EECS/BSAC

• The best software and algorithms for WSN come from UCB/EECS/BSAC