recognizing opportunity clueless toddler unsuspecting victim source of energy the verdict: harvest...
TRANSCRIPT
RECOGNIZING OPPORTUNITY RECOGNIZING OPPORTUNITY
CLUELESS TODDLER
UNSUSPECTING VICTIM
SOURCE OF ENERGY
THE
VERDICT:
HARVEST
HIM
THE POWER OF WALKINGTHE POWER OF WALKING
(1.5W) x (2 steps/sec x 0.6 steps/sec)=
5 W
● Flexible PVDF deflects 0.6 times/sec
● Highly durable
● Easy to cut into appropriate shape
PIEZOELECTRIC SOLE INSERTS PIEZOELECTRIC HEEL INSERTS
● Semi-flexible PZT
● Takes advantage of greatest force
● Heel strike with 130% apparent mass
(12.5%) x (67W)=
8.4 W
8.4 mJ
1.3 mW
8.4 mW
THE SODANO APPROACHTHE SODANO APPROACH
PSI-5H4E (PZT)CAR COMPRESSOR (ACCELEROMETER)
THE PROS:
● At resonant frequency, 40mAh NiMH 1.2V button cell charged in 1 hour
● With a random signal, 40mAh NiMH 1.2V button cell charged in 1.5 hour
● (144C x 1.2v)/3600s = 50mW
● Presents the piezoelectric setup
THE CONS:
● Accelerometer has a completely random frequency (1-1000 Hz)
● 185 PSI-5H4E sheets = $7 316.75
● Extreme brittleness: 0.267mm thick
PIEZOCERAMICS: PZTPIEZOCERAMICS: PZT
● “The direct piezoelectric effect” (Pierre & Jacques Curie in 1880):
Generating of an electric current by applying mechanical stress
● During WWII, the greatest class of piezoelectric elements shifted to man-made FERROELECTRICS:
1. Barium Titanate (BaTiO3B)
2. PZT (Lead Zirconate Titanate)
● PZT is most economical and efficient alternative
TOKYO STATION: MARUNOUCHI TOKYO STATION: MARUNOUCHI NORTH TICKET GATENORTH TICKET GATE
3609 J IN 10 HOURS
● OCTOBER 16 4:00 AM – 2:00 PM
● 785,801 daily commuters on average for the year 2007
KEY ASSUMPTIONS:
● We assume all 785,801 commuters undergo only a one-way commute to work, school, etc.
● Neglect any return-trips that occur 4AM and 2PM that would otherwise increase the number of ‘commuters’
● The same number of commuters walk through the platforms only once between 4AM and 2PM
● Distribute themselves evenly
LOCATING THE TICKET GATESLOCATING THE TICKET GATES
1
6
2 3 45
7
810
1211
9
● 785,555/12 GATES =
65 000 COMMUTERS AT MARUNOUCHI NORTH
1) 65 000/6 PLATFORMS =
10,000 COMMUTERS
2) (3609/6) J / 10,000 COMMUTERS =
60 mJ PER COMMUTER
The piezoelectric floor at Marunouchi North Gate
FINANCINGFINANCING● 480 disc-shaped piezoelectric elements with a diameter of 30 mm
● 480 units x $30/unit = $14 400
● Only units that commuters apply mechanical stress on are productive
“The piezoelectric elements covering the floor are commercially
available ceramic piezoelectric elements”
● Three pairs of footprints
● Two lanes: one proceeding down to Level D and the other proceeding up to Level B
x (3 x 6) x $30/unit =
$6 480
12 x (3 x 6) x $30/unit =
$6 480
SHIELDING AND OUTPUTSHIELDING AND OUTPUT● Rubber matting surrounding the piezoelectric elements in the same plane
● Rubber matting below the circular piezoceramics and shielding them from above
● 1.4 million visitors/year = 3,850 visitors daily
● 3,850 x 2 x 55 mJ = 462 Joules daily
● 462 J x 7 days = 3 234 Joules weekly
PART A: Exhibit Output
PART B: Battery Capacity
● 800mA x 3600 s x 1.2 V = 3456 Joules
A NiMh“green battery”: 800mAh / 1.2V / AAA
WHAT IS IT GOING TO POWER?WHAT IS IT GOING TO POWER?
● Illustrate practicality of piezoelectricity on a small scale
● Power the Robot in the maze in the ‘Roving Mars’ Exhibit
● 2 AA Alkaline batteries as its current power supply
● Batteries replaced once every 2 – 2.5 weeks
● 1 AAA Green battery is recharged once every week; hence, a use-recharge cycle with period of two weeks
THE BOMBSHELLTHE BOMBSHELL
●“After the 3rd week of the experimental period, production of electricity decreased due to a degradation in durability”
● The gargantuan number of commuters at Marunouchi North Ticket Gate eventually oversaw the breakdown of the piezoelectric platformsWHAT IS THE RATE OF DEGRADATION?
10 000 commuters/day x 21 days = 210 000 commuters1.4 million/0.21 million ≈ 7 replacements per annum
7 x $6 480 = $45 360 per annum
THE PIEZO-POWER GATETHE PIEZO-POWER GATE
AB
C
D
E
G
A
B
C
D
E
F
Exhibit Info
Voltmeter
Power Bar
Ammeter
Piezoelectric Platform
F
Piezo-Power Gate Sign
G Electrical Output Info
SUMMARYSUMMARY
-work in progress-work in progress
-debating points to include-debating points to include