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ENERGY SCAVENGING FOR
ELECTRONIC DEVICES
Shailendra Bisariya
Associate Professor, ECE Deptt.
ABESEC Ghaziabad.
1). What is Energy Scavenging?
• “Energy can neither be created nor it can be destroyed.”
• Its not energy harvesting.
• Harvesting is a bountiful and systematic process and there is
a major energy gain (100% activity).
•Scavenging means to feed on the refuse and left overs.
•Energy Scavenging i.e. energy reclaimed from the unused
portion of energy that is dumped.
•This usually helps reduce the dependency on the main source
of energy partially and hence reduces cost by a few % points.
•In short, Scavenging = reclaiming and harvesting =
generation.
Energy scavenging techniques• Photonic:
o Rely on solar energy drawn with the use of photovoltaics
o Solar energy at home - Solar + Wind power
o Not much suitable for electronic devices at present
• Thermal:
o Utilizing Seebeck effect - Differences in temperature between
objects produce thermal gradients that can be used to generate
electricity
o Thermal energy can be converted into electrical energy with a
thermoelectric generator. Such generators are found in hightech wristwatches.
“Energy Scavenging for Mobile and Wireless Electronics”, Joseph A. Paradiso,
Massachusetts Institute of Technology Media Laboratory & Thad Starner, Georgia
Institute of Technology, GVU Center, IEEE 01401839
• The thermic wristwatch uses 10 thermoelectric modules to
generate sufficient microwatts to run its mechanical clock
movement from the small thermal gradient provided by body heat
over ambient temperature.
• Developed an IC with energy consumption of only 0.9 microwatts of power, which was just 3% of that needed in the Quartz
watch.
Chemical : Example Car engine!
o The body gets its energy from glucose, a simple sugar digested
from food.
o Glucose is a renewable, chemical energy source.
o A fuel cell can convert this energy into electrical energy and
power small electronic devices.
o These may one day power medical implants such as pacemakers,
blood sugar and pressure monitors.
ENERGY SCAVENGING FOR ELECTRONIC DEVICES
• Vibrational :
o The two most common methods to generate power are
that of electromagnetic induction and piezoelectricity.
 Electromagnetic generators are based on Faraday‟s Law of
magnetic induction
 Variation in magnetic flux through an electric circuit induces
an open circuit voltage
Shake-driven light-emitting-diode flashlight, IEEE 01401839

Piezo-electric generators**
The piezo-electric effect has been known and used for many
years.
When a piezo-electric crystal is subject to deformed, a potential
appears across the crystal. In this way movement can be used to
create power.
Piezoelectric Frequency Response
These devices would only be used to provide small amounts of
power.
Super capacitor
"Energy Scavenging from Vibrations" IEEE RWEP
Regenerative Braking in Hybrid Cars
"Piezoelectric power generation in tires" Noaman Makki and Remon Pop-Iliev, University
of Ontario Institute of Technology, Oshawa, Canada, SPIE Proc.
An array of PZT bonded to the inner surface of a tire. A dynamometer was
used to test the power.
 The power is measured at various rotations per minute by applying the
output voltage across known resistance values. The average voltage changes
with both load and rpm.
A power of 2.3 watts was produced across this load at 854rpm, roughly
equivalent to 100km/h on the road for the tire size used.
The energy harvested by bonding piezo benders depends on three factors,
namely, tire surface area, rpm at 100km/h, and bender end-to-end deflection.
Recent/Upcoming Electronic devices
Emopulse Smile Smartphone, which is a watch, phone and
bracelet all in one.
• Aside from the usual smartphone features like being able to answer calls,
send text messages, or read social media posts, the Smile has several other
functions that can make it a must-have gadget for anyone.
• It has an „artificial intelligence‟ that can read the user‟s moods. It can tell
when the user is relaxed or stressed out.
• It can also monitor one‟s health and diet.
• It can make suggestions on where to go for a fun night in town.
• It can hold incoming calls or tell the caller to call back.
• It has sound playback, three cameras and even desktop quality gaming
features, too.
• The Smile also has the NFC wireless payment system built into it.
• Emopulse has launched an Indiegogo campaign where interested customers
can pre-order the Smile. Production of the smartphone bracelet will begin at
the end of this year 2013.
ZYPAD wrist wearable computer
Advancement in technology
• Battery technology
• Super capacitors
• Nano generators
 Less Power requirement is possible now to operate
such devices.
Energy Scavenging from Human Power
• Reduced power requirements can be fulfilled by utilizing
energy from human movements.
Generation of power with human activities
Data Analysis
 20 reds dot from 0.5Hz to 40Hz are plotted to show the dominant frequency
 So when we look at the data the top 3, neck, arm, wrist are mostly low
frequency.
 On the other hand the bottom 3, waist, knee and ankle are higher than top
3 frequency.
 This means that lower body generate more power than upper body.
Shoe generator
• Piezotransducer is a high impedance source
=>
high voltages (50-500 V) but low currents
(~100 μA) are generated
• Applications require low voltage (~3 V) and modest current
(1-10 mA)
Some Interesting Facts
 A typical adult can create 100 to 300 watts of
power by pedaling.
 If one pedals and creates an average amount,
200 watts of power and keeps pedaling for 2
hours, 400 Watt-Hours of energy can be
created.
 With this 400 Watt-hour stored in the battery,
one can power:
 A 400 watt TV for 1 hour
 A 200 Watt TV for 2 hours
 A 40 Watt laptop PC for 10
 A 15 Watt fluorescent bulb for almost 27 hours
Walking !!
 Most of us prefer cars for even small distances.
 We even complain of not allowing bikes in campus.
Assume:
Hostel to Institute: 1Km
You go Once a day: 2Km/day
Bikes Average: 60Km/lt
Daily Consumption: 0.033lt
Assume: 200 working days
Yearly consumption: 6.6lt
Assume Students:5000
Total Petrol saved: 33000 lt /year
Thank you
Questions please?
Who knows -- maybe piezoelectric flooring can also capture the energy of a
headstand.