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.
Received 06 August 2012Accepted 31 January 2013Published online 14 February 2013
The authors would like to thank Sonomax Technologies Inc. and its Industrial Research Chair in In-ear Technologies for its financial support and for providing specific equipment required for the experimental setups.
Article outline: I. INTRODUCTION A. Human body power sources 1. Upper limb motion 2. Walking 3. Body heat 4. Breath 5. Blood pressure and heartbeat 6. Head motion B. Proposed source of power II. EAR CANAL SHAPE AND DEFORMATION A. Geometrical data acquisition B. Geometrical data analysis C. Geometrical characteristics of ear canal deformation III. POWER CAPABILITY OF EAR CANAL DYNAMIC MOTION IV. EAR CANAL DYNAMICS VARIATIONS V. CONCLUSIONS AND FUTURE WORK
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