Transcript Session Title

Understanding Smart Sensors
Using Energy Harvesting to
Power Wireless Sensors
October 11, 2012
Randy Frank
Agenda
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The Energy Harvesting System
Energy Harvesting Techniques
Storage Techniques
The Energy Budget
Tools to Get Started
Energy Harvesting
• Avoids battery replacements
Energy
Source
Desired
Measurement
Energy
Harvester
Energy
Storage
Sensor
Power
Management
Microcontroller
Transceiver
Energy Harvesting Techniques
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•
•
•
•
Thermoelectric
Vibration
Solar
Electromechanical
RF
Energy Harvesting Sources
Energy Source
Maximum Power
(µW/cm2)
Vibration/Motion
Human activity
Industrial
4
100
Human activity
Industrial
25
10,000
Thermal
Light/Solar (Photovoltaic)
Indoor
Outdoor
RF Radiation
GSM cellular (900 MHz)
WiFi (2.4 GHz)
10
10,000
0.1
0.01
Energy Harvesting Applications
Automobiles
Bridges/Structures
Building Automation
Industrial Automation
Remote Wireless Sensing
Bulk TEG
Source: Marlow Industries
MEMS TEG
Source: Micropelt
Vibration Sensing
Source: KCF Technologies
Photovoltaic EH
Light Source
34W Fluorescent, 200 cm
34W Fluorescent, 10 cm
60W Incandescent, 100 cm
60W Incandescent, 10 cm
Window sill, cloudy day
Window sill, sunny day
Outdoors, sunny day
Indoors, 1500W Halogen, 1 m
Indoors, 1500W Halogen, 3 m
Source: MicroStrain
Output Power
(In µW)
76
1368
942
4728
1564
19554
20612
6512
1258
Electromechanical Energy Harvesting
• Perpetuum
Perpetuum
Electromechanical EH
• Switch activated energy
harvesting
• When the spring of
EnOcean’s ECO 200 snaps,
electromagnetic induction
produces a short voltage
pulse lasting a few
milliseconds
Converted energy transmits a signal up to a few hundred meters
Source: EnOcean
RF EH
• Powercast
Source: Powercast
RF EH
Source: Powercast
Storage Techniques
• Thin-film, solid state batteries
– Cymbet
– Infinite Power Solutions
• Ultracapacitors
– CAP-XX
IPS
Energy Harvesting: The Energy Budget
• Every component must be scrutinized for its
contribution or power consumption.
Energy
Source
Desired
Measurement
Energy
Harvester
Energy
Storage
Sensor
Power
Management
Microcontroller
Transceiver
Vibration Sources
Energy For Transmitting
Source: Cymbet
3
NC
14
VCAP
NC
9
8
Boost
Converter
RF to DC
Converter
11
VOUT
10
VSET
6
INT
RESET
7
5
13
DOUT
4
12
DSET
2
GND
Voltage
Monitor
GND
RFIN
1
GND
• Many development
kits/tools to get started
• Powercast
• Microchip Technology
NC
Energy Harvesting Development Kits
Radio module
Microcontroller
Capacitor
Sensors
Temp/Humidity/Light
IPS-EVAL-EH-02
• Demonstrates wireless
indoor environmental
sensing, energy harvesting,
energy storage and power
regulation for the
development of
autonomously powered
wireless sensor systems.
• MCU and radio Microchip
Infinite Power Solutions
IPS-EVAL-EH-02
• Multiple indoor
environmental sensors:
– Passive Infra-Red (PIR)
occupancy sensor
– Humidity sensor
– Ambient light sensor
– Temperature sensor
• MAX17710 device from
Maxim Integrated Products
Infinite Power Solutions
Solar Energy Harvesting Development
Kit
Uses Microchip Technology’s
PIC® MCUs with eXtreme Low
Power (XLP)
• sleep currents down to 20nA
• active mode currents down to
50uA/MHz
• code execution efficiency, and
• multiple wake-up sources.
Uses EnerChip storage devices
from Cymbet
Solar Energy Harvesting
Development Kit
• TI’s eZ430-RF2500-SEH
• Includes high-efficiency solar
(2.25x2.25”) panel optimized
for operating indoors
• Manages and stores additional
energy in a pair of thin-film
rechargeable EnerChips from
Cymbet
TI’s eZ430-RF2500 runs the energy harvesting application.
Characterizing the Environment
• Midé Slam Stick Vibration Recorder
Combined Piezoelectric and Solar
• Piezoelectric Vibration & Solar Energy
Harvester, SEH25w from Midé
• Volture Piezoelectric Vibration Energy
Harvester
Summary
• Several energy sources for EH
• Power is limited, budget wisely
• EH systems are complex but many
development tools are available
Topics Later This Week
• Friday
Current hot topic 2: Sensor Fusion - Using the
Newest Techniques for Advanced Sensors