Ear canal deformation caused by temporomandibular joint (jaw joint) activity, also known as “ear canal dynamic motion,” is introduced in this paper as a candidate source of power to possibly recharge hearing aid batteries. The geometrical deformation of the ear canal is quantified in 3D by laser scanning of different custom ear moulds. An experimental setup is proposed to measure the amount of power potentially available from this source. The results show that 9 mW of power is available from a 15 mm3 dynamic change in the ear canal volume. Finally, the dynamic motion and power capability of the ear canal are investigated in a group of 12 subjects.

1.
World Health Organization, “
Deafness and hearing impairment
,” Tech. Rep. Fact sheet No. 300 (
2010
).
2.
P.
Qiao
,
H.
Corporaal
, and
M.
Lindwer
, “
A 0.964 mW digital hearing aid system
,” in
DATE 2011—Design, Automation and Test in Europe
(Grenoble,
2011
), pp.
1
4
.
3.
T.
Starner
, “
Human-powered wearable computing
,”
IBM Syst. J.
35
,
618
629
(
1996
).
4.
J. M.
Donelan
,
Q.
Li
,
V.
Naing
,
J. A.
Hoffer
,
D. J.
Weber
, and
A. D.
Kuo
, “
Biomechanical energy harvesting: Generating electricity during walking with minimal user effort
,”
Science (N.Y.)
319
,
807
810
(
2008
).
5.
L. C.
Rome
,
L.
Flynn
,
E. M.
Goldman
, and
T. D.
Yoo
, “
Generating electricity while walking with loads
,”
Science (N.Y.)
309
,
1725
1728
(
2005
).
6.
A.
Lay-Ekuakille
,
G.
Vendramin
,
A.
Trotta
, and
G.
Mazzotta
, “
Thermoelectric generator design based on power from body heat for biomedical autonomous devices
,” in
2009 IEEE International Workshop on Medical Measurements and Applications
(
IEEE
,
Cetraro
,
2009
), pp.
1
4
.
7.
E.
Goll
,
H.-P.
Zenner
, and
E.
Dalhoff
, “
Upper bounds for energy harvesting in the region of the human head
,”
IEEE Trans. Biomed. Eng.
58
,
3097
3103
(
2011
).
8.
A.
Delnavaz
and
J.
Voix
, “
Electromagnetic micro-power generator for energy harvesting from breathing
,” in
IECON 2012—38th Annual Conference on IEEE Industrial Electronics Society
(
IEEE
,
2012
), pp.
984
988
.
9.
A.
Pfenniger
,
V. M.
Koch
, and
R.
Vogel
, “
Human energy harvesting by intravascular turbine generators
,” in
Proceedings of the 6th International Conference on Microtechnologies in Medicine and Biology (MMB 2011)
(Lucerne, Switzerland,
2011
).
10.
M.
Amin Karami
and
D. J.
Inman
, “
Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters
,”
Appl. Phys. Lett.
100
,
042901
(
2012
).
11.
C.
Pirzanski
, “
Earmolds and hearing aid shells: A tutorial Part 2: Impression-taking techniques that result in fewer remakes
,”
Hear. Rev.
12
,
39
46
(
2005
).
12.
C.
Pirzanski
and
B.
Berge
, “
Ear canal dynamics: Facts versus perception
,”
Hear. J.
58
,
50
58
(
2005
).
13.
R.
Oliveira
,
M.
Babcock
,
M.
Venem
,
G.
Hoeker
,
B.
Parish
, and
V.
Kolpe
, “
The dynamic ear canal and its implications
,”
Hear. Rev.
12
,
18
19
(
2005
).
14.
M. R.
Stinson
and
B. W.
Lawton
, “
Specification of the geometry of the human ear canal for the prediction of sound-pressure level distribution
,”
J. Acoust. Soc. Am.
85
,
2492
2503
(
1989
).
15.
D. P.
Egolf
, “
Quantifying ear-canal geometry with multiple computer-assisted tomographic scans
,”
J. Acoust. Soc. Am.
93
,
2809
(
1993
).
16.
T.
Baer
, “
Analysis of vocal tract shape and dimensions using magnetic resonance imaging: Vowels
,”
J. Acoust. Soc. Am.
90
,
799
(
1991
).
17.
S.
Darkner
,
R.
Larsen
, and
R. R.
Paulsen
, “
Analysis of deformation of the human ear and canal caused by mandibular movement
,” in
International Conference on Medical image computing and computer-assisted intervention: MICCAI
(
2007
), Vol. 10, pp.
801
808
.
18.
J.
Voix
and
F.
Laville
, “
The objective measurement of individual earplug field performance
,”
J. Acoust. Soc. Am.
125
,
3722
3732
(
2009
).
19.
M. C.
Turcot
and
J.
Voix
, “
Pressure regulation mechanism for inflatable in-ear device
,” U.S. patent application 20110079227 (
2011
).
20.
A.
Delnavaz
and
J.
Voix
, “
Energy harvesting for in-ear devices using ear canal dynamic motion
,”
IEEE Trans. Ind. Electron.
(in press).
21.
C.
Pirzanski
, “
Earmolds: Are soft materials superior?
Hear. J.
54
,
36
42
(
2001
).
You do not currently have access to this content.