Novel in-ear technology could allow chewing to replace the batteries in hearing aids

https://medicalxpress.com/news/2022-06-in-ear-technology-batteries-aids.html

"modelling the deformations of the ear canal created by the movements of the jaw... action of eating for 50 minutes would be enough to generate all the energy necessary for a day's use of the hearing aid. For this experiment, the researchers placed an earplug filled with water in the ear of the participants. They then measured the pressure in the earplug created by the jaw movements. Finally, they translated these pressure variations into deformations of the ear canal"