I saw something where someone tried to do that - https://hackaday.com/2020/01/02/assistive-technolgy-switch-is-actuated-using-your-ear-muscles/ https://hackaday

I saw something where someone tried to do that - https://hackaday.com/2020/01/02/assistive-technolgy-switch-is-actuated-using-your-ear-muscles/ https://hackaday.com/2020/01/02/assistive-technolgy-switch-i... It seems to use a type of camera to measure movement in the ear.