Heart-powered pacemaker could one day eliminate battery-replacement surgery. This could also reduce the size of the pacemaker dramatically. Further information: http://bit.ly/1BmrBeL
9. Pacemakers
โข Power requirement of modern pacemakers has
now reduced to one microwatt.
โข The size of the pacemaker is 42mm X 51mm X
6mm
โข The batteries take up about 2/3rd of the size of
the pacemakerโs generator.
โข A pacemakerโs batteries last for only 5 - 7 years.
[1]
10. Piezoelectric Pacemakers
โข Piezoelectricity generated from mechanical
vibrations in our chest area could be used to
power the pacemaker.[1]
โข M. Amin Karami and Daniel J. Inman, Phds from
the Aerospace Engineering Dept. of University of
Michigan have proposed have proposed this
concept.[6]
11. Piezoelectricity
โข An electric charge accumulates in certain solid
materials in response to mechanical stress.
โข Common piezoelectric materials :-
Natural crystals - quartz, rochelle salt, topaz
Synthetic crystals - Gallium orthophosphate, a
quartz analogic crystal
โข The most common piezo electric material used is
Lead zirconate titanate.
[7]
12. Piezoelectric Pacemaker
โข Vibrations produced by our beating heart our used
to generate electricity to power the pacemaker
โข The piezoelectric energy harvester is placed in the
vicinity of the heart
โข The vibrations in the vicinity of our heart are
estimated using ultrasonic velocity measurements
performed by Kanai H. in a paper published by
IEEE.
[1]
13. Piezoelectric energy
harvester
โข A unimorph zigzag geometry piezoelectric structure is used so
that:
- its size remains small
- the natural frequency vibrations it responds to our within the
range of our heartโs frequency
- it is designed to have high strength
โข The researchers target reducing the power source area by 50%.
[1]
14. Specifics
โข the zigzag energy harvesters have 27mm long beams
โข brass is chosen as the suitable substrate material
โข the piezoelectric material used is Lead Zirconate
Titanate (PZT-5A)
โข the piezoelectric layer is attached to the substrate
using poly-epoxide.
โข the thickness of the PZT-5A used is 0.01 in (254um).
[1]
15. Specifics
โข The maximum power harvested corresponds to
1800 um substrate thickness if excited at nominal
heart rate.
โข The power output from such structure is 10 uW,
which is 10 times the power requirement of a
pacemaker
โข This type of piezoelectric energy harvester is called
linear energy harvester and it harvests energy in
response to 39 Hz oscillations.
[1]
16. Limitations & Further
improvements
โข Linear harvesters work well only at a specific heart rate, so
heart rate changes in patients with an irregular heart rate
could prevent them from harvesting enough power.[4]
โข To overcome this limitation in patients who have a relatively
irregular heart rate, nonlinear broadband energy harvesters
are used.[4]
โข A nonlinear harvester uses magnets to enhance power
production and make the harvester less sensitive to heart
rate changes. The nonlinear harvester generated enough
power from heartbeats ranging from 20 to 600 beats per
minute to continuously power a pacemaker.[5]
17. โข Karami told the Daily Mail that, โWhat we have
proven is that under optimal conditions, this
concept is working.โ I donโt know that that would
be enough to put my life on the line. But if the
device proves itself and manages to pass all the
regulatory lines of defense, it could be a real
boon to heart patients.And itโs a large market
opportunity for device-makers, too: some 700,000
people get a pacemaker or defibrillator each year,
reportedly.[2]
18. Citations
โข [1] Powering pacemakers from heartbeat vibrations using linear and nonlinear energy
harvesters by M. Amin Karami and Daniel J. Inman, Applied Physics Letters, 23rd
January 2012
โข [2] A Heartbeat-Powered Pacemaker - MIT Technology Review, Nov 7 2012
โข [3] New device could allow your heartbeat to power pacemaker - American Heart
Association, Nov 04, 2012
โข [4] UMich researchers closer to producing piezo-powered pacemaker - The American
Ceramic Society, March 05, 2012
โข [5] No More Batteries: Piezoelectric Pacemaker Powered By The Heart - Science 2.0,
Nov 4, 2012
โข [6] Heart-powered pacemaker could one day eliminate battery-replacement surgery -
University of Michigan News, March 02, 2012
โข [7] Piezoelectricity - Wikipedia Article