OpenEarable v1.4 Earpiece

Earpiece extension for the OpenEarable with dual microphones, one into the ear canal and one outside. Both microphones are ultrasound capabale. A paper about the earpiece is published here:  https://doi.org/10.1145/3675094.3678483

We validate the earpiece by showcasing its abilities to occlude the ear canal and measure the heartbeat of a wearer.