Modular auricular sensing system

The technology provides a modular auricular sensing system which can be used for biometric sensing in a variety of applications. The sensing system includes an earpiece module and an electronics module. The earpiece module includes a housing and one or more electrodes with contacts along an exterior surface of the housing. The earpiece module has a first end portion configured for at least partial insertion into the ear canal and a second end portion releasably coupled to the electronics module. The coupling between the earpiece module and the electronics module is configured to allow relative movement (e.g., translation and/or rotation) between the earpiece module and the electronics module while maintaining electrical connectivity between electrode(s) of the earpiece module and the electronics module.