PowerPoint PresentationEmbedded and Adaptive Computing Group
Hande, Nov 2005
Dinesh Bhatia
Associate Professor
Abhiman Hande
Research Associate
November 23, 2005
Embedded and Adaptive Computing Group
Hande, Nov 2005
Necessity for alternate sources of energy
Available alternative energy sources
ZigBeeTM Alliance | Wireless Control That Simply Works
Embedded and Adaptive Computing Group
Hande, Nov 2005
ZigBeeTM Alliance | Wireless Control That Simply Works
Embedded and Adaptive Computing Group
Hande, Nov 2005
Harvesting technology
Power density
15 mW/cm2
Embedded and Adaptive Computing Group
Hande, Nov 2005
Batteries
Li-ion
NiCD
NiMH
Ultracapacitors
Maxwell
Samsung
NEC
ZigBeeTM Alliance | Wireless Control That Simply Works
Embedded and Adaptive Computing Group
Hande, Nov 2005
Energy Harvesting for Wireless Sensor Nodes
Block diagram of an energy harvesting wireless sensing node with data logging and bidirectional RF communications capabilities
VCC
RF communication link
Energy source
Embedded and Adaptive Computing Group
Hande, Nov 2005
Solar Cell Characteristics
10-20 % efficiency outdoors
<1% efficiency indoors
V-I characteristics of a Solar World 4-4.0-100 solar panel
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Embedded and Adaptive Computing Group
Hande, Nov 2005
Embedded and Adaptive Computing Group
Hande, Nov 2005
Vibrations to Electricity
Embedded and Adaptive Computing Group
Hande, Nov 2005
Comparison of Vibrations to Electricity Methods
Scavenging the power from commonly occurring vibrations for use by low power wireless systems is both feasible and attractive for certain applications.
Piezoelectric converters appear to be the most attractive for meso-scale devices with a maximum demonstrated power density of approximately 200 μW/cm3 vs. 100 μW/cm3 for capacitive MEMS devices.
Electromagnetic converters provide maximum voltage of 0.1 volts
ZigBeeTM Alliance | Wireless Control That Simply Works
Embedded and Adaptive Computing Group
Hande, Nov 2005
Piezo Converter Set-up
Embedded and Adaptive Computing Group
Hande, Nov 2005
Monitor available energy level
Solar panels / piezoelectric element
VCC to
Embedded and Adaptive Computing Group
Hande, Nov 2005
CrossbowTM MICAz motes
Mesh networking protocol
MICAz mote
MICA2 motes
Embedded and Adaptive Computing Group
Hande, Nov 2005
Battery Life Estimation for a MICAz Mote
Battery life estimation for a MICAz mote operating at 1% duty cycle
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Embedded and Adaptive Computing Group
Hande, Nov 2005
Dual energy storage scheme
Tentative research timeline
Task 3: Identify appropriate components for procurement
Task 4: Implement the prototype designs
Task 5: Testing and modifications
SP SU FA
Embedded and Adaptive Computing Group
Hande, Nov 2005
Conclusions
Acceptable power sources remain perhaps the most challenging technical hurdle to the widespread deployment of wireless sensor networks.
While significant progress has been made in many areas including indoor photovoltaic systems, micro-fuel cells, thermoelectrics, micro-heat engines, and vibration-to-electricity conversion, much more research and new approaches need to be pursued.
Harvesting technology Power density
2
3
Processor
0.0879
Radio
0.0920
Battery Capacity (mAhr)
Battery Life (months)